Surface emitting laser

Abstract

The present invention provides a surface emitting laser that makes it possible to obtain gain necessary for oscillation regardless of resonator length and that makes it possible to control a transverse mode.　A surface emitting laser according to the present technology comprises a first reflective structure, a second reflective structure, and an intermediate structure which is sandwiched between the first reflective structure and the second reflective structure and which includes an active layer, wherein the first reflective structure has at least one convex surface that protrudes toward the opposite side from the second reflective structure side and that has a reflectance distribution and / or reflection direction distribution in the in-plane direction.

Description

Surface-emitting laser

[0001] The technology disclosed herein (hereinafter also referred to as "this technology") relates to a surface-emitting laser.

[0002] Conventionally, vertical cavity surface-emitting lasers (VCSELs), which sandwich the active layer between two reflective structures, are known.

[0003] Some conventional surface-emitting lasers have a reflective structure that has a low-reflectivity region at the periphery (see, for example, Patent Documents 1 to 3).

[0004] Some conventional surface-emitting lasers have a concave mirror as their reflective structure (see, for example, Patent Document 4).

[0005] International Publication No. 2005 / 074080, Japanese Patent Publication No. 2020-155561, Japanese Patent Publication No. 2015-156497, International Publication No. 2018 / 083877

[0006] For example, in the surface-emitting lasers described in Patent Documents 1 to 3, there is room for improvement in obtaining the gain necessary for oscillation regardless of the resonator length.

[0007] For example, Patent Document 4 makes no mention whatsoever of controlling the lateral mode.

[0008] Therefore, the main objective of this technology is to provide a surface-emitting laser that can obtain the gain necessary for oscillation regardless of the resonator length and can control the transverse modes.

[0009] This technology provides a surface-emitting laser comprising: a first reflective structure; a second reflective structure; and an intermediate structure including an active layer sandwiched between the first and second reflective structures, wherein the first reflective structure has at least one convex surface that is convex on the side opposite to the second reflective structure, and has a reflectance distribution and / or reflection direction distribution in the in-plane direction. The first reflective structure may have a first reflectance, which is the reflectance of the central part, and a second reflectance, which is the reflectance of the peripheral part, which are different. The active layer has an emission region, and the central part may overlap with the emission region in a plan view. The second reflectance may be lower than the first reflectance. The convex surface may have a first roughness, which is the roughness of the central part, and a second roughness, which is the roughness of the peripheral part, which are different. The second roughness may be higher than the first roughness. The convex surface may have irregularities in the central part or the peripheral part. The convex surface may have the irregularities in the peripheral part. The convex surface may have an oxide film or a chloride film in its central or peripheral portion. The convex surface may have the oxide film or the chloride film in its peripheral portion. The convex surface may have a radius of curvature distribution in the in-plane direction. The radius of curvature of the central portion of the convex surface may be different from the radius of curvature of the peripheral portion. The first reflective structure may have a first convex surface as the convex surface, and a second convex surface as the convex surface, which is located on the opposite side of the first convex surface from the second reflective structure side. The first reflective structure may include a concave mirror having a concave surface along the first convex surface on the first convex surface side, and the second convex surface on the opposite side from the first convex surface side. The intermediate structure includes a part of the substrate disposed on the first reflective structure side of the active layer, and the first convex surface may be at least a part of the surface of the substrate on the concave mirror side. The first reflective structure may include a plane mirror and a substrate disposed on the opposite side of the plane mirror from the second reflective structure, the substrate having the convex surface on the opposite side from the second reflective structure. An anti-reflective coating may be provided on the convex surface.When the resonator length is L, the radius of curvature of the convex surface is R, the oscillation wavelength is λ, and the average refractive index of the region between the convex surface and the second reflective structure is n, the diameter of the central part is 3[(λ / πn)[LR]. 2 (RL)] 1 / 2 ] 1 / 2 The first and second reflective structures may include at least one dielectric multilayer mirror. The first and second reflective structures may include at least one semiconductor multilayer mirror. The intermediate structure may include a III-V compound semiconductor. The III-V compound semiconductor may be a GaN-based compound semiconductor. The III-V compound semiconductor may be a GaAs-based compound semiconductor. The III-V compound semiconductor may be an InP-based compound semiconductor.

[0010] Figure 3A is a cross-sectional view of a surface-emitting laser according to Example 1 of one embodiment of this technology. Figure 3B is a schematic plan view of the back surface of the substrate of the surface-emitting laser according to Example 1 of one embodiment of this technology. Figure 3A is a schematic cross-sectional view of a surface-emitting laser according to Comparative Example 1. Figure 3B is a schematic cross-sectional view of a surface-emitting laser according to Comparative Example 2. Figure 11A is a schematic cross-sectional view of a surface-emitting laser according to Example 1. This is a flowchart for explaining an example of a method for manufacturing the surface-emitting laser of Figure 1. Figures 6A and 6B are cross-sectional views of each step of an example of a method for manufacturing the surface-emitting laser of Figure 1. Figures 7A and 7B are cross-sectional views of each step of an example of a method for manufacturing the surface-emitting laser of Figure 1. Figures 8A and 8B are cross-sectional views of each step of an example of a method for manufacturing the surface-emitting laser of Figure 1. Figures 9A and 9B are cross-sectional views of each step of an example of a method for manufacturing the surface-emitting laser of Figure 1. Figures 10A and 10B are cross-sectional views of each step of an example of a method for manufacturing the surface-emitting laser of Figure 1. Figures 11A and 11B are cross-sectional views of each step of an example of a method for manufacturing the surface-emitting laser of Figure 1. This is a cross-sectional view of a surface-emitting laser according to Example 2 of one embodiment of this technology. This is a cross-sectional view of a surface-emitting laser according to Example 3 of one embodiment of this technology. This is a cross-sectional view of a surface-emitting laser according to Example 4 of one embodiment of this technology. This is a cross-sectional view of a surface-emitting laser according to Example 5 of one embodiment of this technology. This is a flowchart illustrating an example of a method for manufacturing the surface-emitting laser of Figure 15. Figures 17A and 17B are cross-sectional views of each step of an example of a method for manufacturing the surface-emitting laser of Figure 15. Figures 18A and 18B are cross-sectional views of each step of an example of a method for manufacturing the surface-emitting laser of Figure 15. Figures 19A and 19B are cross-sectional views of each step of an example of a method for manufacturing the surface-emitting laser of Figure 15. Figures 20A and 20B are cross-sectional views of each step of an example of a method for manufacturing the surface-emitting laser of Figure 15. Figures 21A and 21B are cross-sectional views of each step of an example of a method for manufacturing the surface-emitting laser of Figure 15. This is a cross-sectional view of a surface-emitting laser according to Example 6 of one embodiment of this technology. This is a cross-sectional view of a surface-emitting laser according to Example 7 of one embodiment of this technology. This is a flowchart illustrating an example of a method for manufacturing the surface-emitting laser of Figure 23. Figures 25A and 25B are cross-sectional views of each step in an example of the manufacturing method of the surface-emitting laser shown in Figure 23. Figure 25A and 25B are cross-sectional views of each step in an example of the manufacturing method of the surface-emitting laser shown in Figure 23. Figure 25A is a cross-sectional view of a surface-emitting laser according to Example 8 of one embodiment of this technology.This is a cross-sectional view of a surface-emitting laser according to Example 9 of one embodiment of this technology. This is a cross-sectional view of a surface-emitting laser according to Example 10 of one embodiment of this technology. This is a cross-sectional view of a surface-emitting laser according to Example 11 of one embodiment of this technology. This is a cross-sectional view of a surface-emitting laser according to Example 12 of one embodiment of this technology. This is a cross-sectional view of a surface-emitting laser according to Example 13 of one embodiment of this technology. This is a cross-sectional view of a surface-emitting laser according to Example 14 of one embodiment of this technology. This is a cross-sectional view of a surface-emitting laser according to Example 15 of one embodiment of this technology. This is a cross-sectional view of a surface-emitting laser according to Example 16 of one embodiment of this technology. This is a cross-sectional view of a surface-emitting laser according to Example 16.5 of one embodiment of this technology. This is a cross-sectional view of a surface-emitting laser according to Example 17 of one embodiment of this technology. This is a cross-sectional view of a surface-emitting laser according to Example 17.5 of one embodiment of this technology. This is a cross-sectional view of a surface-emitting laser according to Example 18 of one embodiment of this technology. This is a cross-sectional view of a surface-emitting laser according to Example 19 of one embodiment of this technology. This is a cross-sectional view of a surface-emitting laser according to Example 20 of one embodiment of this technology. This is a cross-sectional view of a surface-emitting laser according to Example 21 of one embodiment of this technology. This is a cross-sectional view of a surface-emitting laser array according to Example 22 of one embodiment of this technology. This is a cross-sectional view of a surface-emitting laser according to Example 23 of one embodiment of this technology. This is a cross-sectional view of a surface-emitting laser according to Example 24 of one embodiment of this technology. This is a cross-sectional view of a surface-emitting laser according to Example 25 of one embodiment of this technology. This is a cross-sectional view of a surface-emitting laser according to Example 26 of one embodiment of this technology. This is a cross-sectional view of a surface-emitting laser according to Example 27 of one embodiment of this technology. This is a cross-sectional view of a surface-emitting laser according to Example 28 of one embodiment of this technology. This is a cross-sectional view of a surface-emitting laser according to Example 29 of one embodiment of this technology. This is a cross-sectional view of a surface-emitting laser according to Example 30 of one embodiment of this technology. This is a cross-sectional view of a surface-emitting laser according to Example 31 of one embodiment of this technology. This is a cross-sectional view of a surface-emitting laser according to Example 32 of one embodiment of this technology. This is a cross-sectional view of a surface-emitting laser according to Example 33 of one embodiment of this technology. This is a cross-sectional view of a surface-emitting laser according to Example 34 of one embodiment of this technology. This is a cross-sectional view of a surface-emitting laser according to Example 35 of one embodiment of this technology. This is a cross-sectional view of a surface-emitting laser according to Example 36 of one embodiment of this technology. This is a cross-sectional view of a surface-emitting laser according to Example 37 of one embodiment of this technology.This is a cross-sectional view of a surface-emitting laser according to Example 38 of one embodiment of this technology. This is a cross-sectional view of a surface-emitting laser according to Example 39 of one embodiment of this technology. This is a cross-sectional view of a surface-emitting laser according to Example 40 of one embodiment of this technology. This is a cross-sectional view of a surface-emitting laser according to Example 41 of one embodiment of this technology. This is a cross-sectional view of a surface-emitting laser according to Example 42 of one embodiment of this technology. This is a cross-sectional view of a surface-emitting laser according to Example 43 of one embodiment of this technology. This is a diagram showing an example of the application of a surface-emitting laser according to this technology to a distance measuring device. This is a block diagram showing an example of the schematic configuration of a vehicle control system. This is an explanatory diagram showing an example of the installation position of a distance measuring device.

[0011] Preferred embodiments of the present technology will be described in detail below with reference to the attached drawings. In this specification and the drawings, components having substantially the same functional configuration are denoted by the same reference numerals, and redundant explanations will be omitted. The embodiments described below represent typical embodiments of the present technology and should not be interpreted as narrowing the scope of the present technology. Even if this specification describes that the surface-emitting laser according to the present technology has multiple effects, it is sufficient for the surface-emitting laser according to the present technology to have at least one effect. The effects described in this specification are merely examples and are not limiting, and other effects may also be present.

[0012] Furthermore, the following explanation will be given in this order: 1. Surface-emitting laser according to Example 1 of one embodiment of this technology 2. Surface-emitting laser according to Example 2 of one embodiment of this technology 3. Surface-emitting laser according to Example 3 of one embodiment of this technology 4. Surface-emitting laser according to Example 4 of one embodiment of this technology 5. Surface-emitting laser according to Example 5 of one embodiment of this technology 6. Surface-emitting laser according to Example 6 of one embodiment of this technology 7. Surface-emitting laser according to Example 7 of one embodiment of this technology 8. Surface-emitting laser according to Example 8 of one embodiment of this technology 9. Surface-emitting laser according to Example 9 of one embodiment of this technology 10. Surface-emitting laser according to Example 10 of one embodiment of this technology 11. Surface-emitting laser according to Example 11 of one embodiment of this technology 12. Surface-emitting laser according to Example 12 of one embodiment of this technology 13. Surface-emitting laser according to Example 13 of one embodiment of this technology 14. Surface-emitting laser according to Example 14 of one embodiment of this technology 15. Surface-emitting laser according to Example 15 of one embodiment of this technology 16. Surface-emitting laser according to Example 16 of one embodiment of this technology 16.5. Surface-emitting laser according to Example 16.5 of one embodiment of this technology 17. Surface-emitting laser according to Example 17 of one embodiment of this technology 17.5. Surface-emitting laser according to Example 17.5 of one embodiment of this technology 18. Surface-emitting laser according to Example 18 of one embodiment of this technology 19. Surface-emitting laser according to Example 19 of one embodiment of this technology 20. Surface-emitting laser according to Example 20 of one embodiment of this technology 21. Surface-emitting laser according to Example 21 of one embodiment of this technology 22. Surface-emitting laser according to Example 22 of one embodiment of this technology 23. Surface-emitting laser according to Example 23 of one embodiment of this technology 24. Surface-emitting laser according to Example 24 of one embodiment of this technology 25. Surface-emitting laser according to Example 25 of one embodiment of this technology 26. Surface-emitting laser according to Example 26 of one embodiment of this technology 27. Surface-emitting laser according to Example 27 of one embodiment of this technology 28. Surface-emitting laser according to Example 28 of one embodiment of this technology 29. Surface-emitting laser according to Example 29 of one embodiment of this technology 30. Surface-emitting laser according to Example 30 of one embodiment of this technology 31. Surface-emitting laser according to Example 31 of one embodiment of this technology 32. 33. Surface-emitting laser according to Example 32 of one embodiment of this technology. 34. Surface-emitting laser according to Example 34 of one embodiment of this technology. 35. Surface-emitting laser according to Example 35 of one embodiment of this technology. 36. Surface-emitting laser according to Example 36 of one embodiment of this technology. 37. Surface-emitting laser according to Example 37 of one embodiment of this technology. 38. Surface-emitting laser according to Example 38 of one embodiment of this technology. 39. Surface-emitting laser according to Example 39 of one embodiment of this technology. 40. Surface-emitting laser according to Example 40 of one embodiment of this technology. 41. Surface-emitting laser according to Example 41 of one embodiment of this technology. 42. Surface-emitting laser according to Example 42 of one embodiment of this technology. 43. Surface-emitting laser according to Example 43 of one embodiment of this technology. 44. Modifications of this technology. 45. Examples of applications to electronic devices. 46. Example of applying a surface-emitting laser to a distance measuring device. 47. Example of mounting a distance measuring device on a mobile device.

[0013] Below, one embodiment of the surface-emitting laser relating to this technology will be described in detail with reference to several examples. For convenience, in the following description, the upper side of the cross-sectional view such as Figure 1 will be referred to as "upper" and the lower side as "lower".

[0014] <1. Surface-emitting laser according to Example 1 of one embodiment of the present technology> Hereinafter, a surface-emitting laser according to Example 1 of one embodiment of the present technology will be described with reference to the drawings.

[0015] <<Configuration of Surface-Emitting Laser>> Figure 1 is a cross-sectional view of a surface-emitting laser 10 according to Embodiment 1 of one embodiment of this technology. Figure 2 is a schematic plan view of the back surface of the substrate 101 of the surface-emitting laser 10.

[0016] (Overall Configuration) As an example, the surface-emitting laser 10 comprises a first reflective structure RS1, a second reflective structure RS2, and an intermediate structure MS containing an active layer 103 sandwiched between the first reflective structure RS1 and the second reflective structure RS2, as shown in Figure 1. The first and second reflective structures RS1 and RS2 are stacked on top of each other via the intermediate structure MS. That is, the surface-emitting laser 10 is a Vertical Cavity Surface Emitting Laser (VCSEL). As an example, the surface-emitting laser 10 is a surface-emitting laser. The surface-emitting laser 10 is driven by, for example, a laser driver. Hereinafter, the direction in which the first and second reflective structures RS1 and RS2 are stacked will also be referred to as the "stacking direction".

[0017] The surface-emitting laser 10 is, for example, a GaN-based VCSEL in which the intermediate structure MS is a III-V compound semiconductor, such as a GaN-based compound semiconductor (a compound semiconductor lattice-matched to GaN). The oscillation wavelength of the surface-emitting laser 10 is, for example, 370 nm to 650 nm (e.g., 455 nm).

[0018] The resonator is composed of first and second reflective structures RS1 and RS2 and an active layer 103. The resonator length L of the resonator (distance between the first and second reflective structures RS1 and RS2) is preferably, for example, 10 to 100 μm, and more preferably 20 to 50 μm (for example, 22.4 μm). The total thickness of the surface-emitting laser 10 is preferably, for example, 200 μm or less.

[0019] The first reflective structure RS1, as an example, has at least one (for example, more) convex surfaces that are convex on the side opposite to (downward from) the second reflective structure RS2.

[0020] Specifically, the first reflective structure RS1, as an example, has a first convex surface 101a and a second convex surface 108a, which is located on the opposite side (lower side) of the first convex surface 101a from the second reflective structure RS2 side.

[0021] More specifically, the first reflective structure RS1 includes, as an example, a concave mirror as the first reflector 108, which has a concave surface 108b along the first convex surface 101a on the side of the first convex surface 101a (upper side), and a second convex surface 108a on the opposite side from the first convex surface 101a (lower side). The first convex surface 101a is the surface on the side of the first reflector 108 (lower side) of the substrate 101 which is located on the side of the first reflective structure RS1 (lower side) of the active layer 103.

[0022] The intermediate structure MS includes, in addition to the active layer 103, a portion of the substrate 101 (the portion other than the first convex surface 101a), the first and second cladding layers 102 and 104, the insulating layer 105, and the transparent conductive film 106.

[0023] The first and second cladding layers 102 and 104 are arranged on the substrate 101 so as to sandwich the active layer 103 from above and below. Each of the first and second cladding layers 102 and 104 has a different conductivity type and a larger bandgap energy than the active layer 103. In other words, the surface-emitting laser 10 has a double heterostructure in which the active layer 103 is sandwiched between the first and second cladding layers 102 and 104.

[0024] The insulating layer 105 is an insulating layer having an opening 105a in the center and is placed on the second cladding layer 104.

[0025] The transparent conductive film 106 is positioned such that its central portion is located within the opening 105a of the insulating layer 105 and is in contact with the second cladding layer 104, and its peripheral portion is located on the insulating layer 105, at least in the area surrounding the opening 105a.

[0026] The insulating layer 105 has higher resistance and a lower refractive index than the transparent conductive film 106, and therefore functions as a current / light constriction layer. The central part of the transparent conductive film 106 located within the opening 105a of the insulating layer 105 becomes the current / light passage region. The insulating layer 105 defines the light-emitting region (current injection region) of the active layer 103.

[0027] The surface-emitting laser 10 has an anode electrode 109 and a cathode electrode 111 for injecting current into the active layer 103.

[0028] As an example, the anode electrode 109 is circumferential in plan view (for example, ring-shaped), with its outer periphery located on the insulating layer 105 and its inner periphery located on the peripheral portion of the transparent conductive film 106.

[0029] As an example, the cathode electrode 111 is provided on the electrode mounting portion 101b, which is the bottom surface of a stepped portion provided on the substrate 101.

[0030] The second reflective structure RS2 includes, as an example, a plane mirror as the second reflector 107. The plane mirror as the second reflector 107 is, as an example, partially positioned on the transparent conductive film 106 on the inner diameter side of the anode electrode 109, and the other part positioned on the inner circumference of the anode electrode 109. The plane mirror as the second reflector 107 is the reflector on the emission side.

[0031] (Substrate) The substrate 101 is made of, for example, an n-GaN substrate. The refractive index of GaN is, for example, 2.38. The protruding portion having a first convex surface 101a that protrudes toward the first reflecting mirror 108 side (downward side) relative to the substantially flat portion of the back surface (bottom surface) of the substrate 101 is also called a "lens-shaped portion" because it has a lens-like shape. The first convex surface 101a is a curved surface such as a sphere or a parabolic surface. The diameter r of the lens-shaped portion is, for example, 30 to 50 μm. The radius of curvature (RCC) of the first convex surface 101a is, as an example, 10 to 400 μm (for example, 31.1 μm).

[0032] (First Reflector) By having the first reflection structure RS1 include a concave mirror with positive power as the first reflector 108, diffraction loss can be reduced by lateral optical field confinement. As a result, even with a long resonator length L, the gain required for oscillation can be obtained. The first reflector 108 is, for example, composed of a dielectric multilayer mirror. The dielectric multilayer mirror has little light absorption and has high reflectivity and insulation properties. The multilayer mirror is also called a distributed Bragg reflector (DBR). The dielectric multilayer mirror has a structure in which high refractive index layers and low refractive index layers with different refractive indices are alternately stacked with an optical thickness of 1 / 4 wavelength of the emission wavelength of the active layer 103. The dielectric multilayer mirror is preferably made of a material containing at least one of, for example, SiO2, TiO2, Ta2O5, SiN, a-Si, MgF2, and CaF2. The thickness of each refractive index layer of the dielectric multilayer mirror is, for example, 127 nm, and the number of pairs is, for example, 7.5 pairs or more. The radius of curvature of the concave mirror is, for example, 10 to 400 μm (for example, 31.1 μm). The planar shape of the concave mirror is, for example, circular, elliptical, etc.

[0033] (First Cladding Layer) The first cladding layer 102 is, for example, an n-type cladding layer and is composed of, for example, an n-GaN layer.

[0034] (Active Layer) The active layer 103 is, for example, an In 0.04 Ga 0.96 N layer (barrier layer) and an In 0.16 Ga 0.84 N layer (well layer) alternately stacked to form a multiple quantum well structure. The region of the active layer 103 corresponding to the opening 105a of the insulating layer 105 becomes the light emitting region 103a. The active layer 103 is preferably disposed at or near the position of the antinode of the standing wave generated in the resonator.

[0035] (Second Cladding Layer) The second cladding layer 104 is, for example, a p-type cladding layer and is composed of, for example, a p-GaN layer.

[0036] (Insulating layer) The insulating layer 105 is made of a dielectric material such as SiO2, SiN, or SiON. The current and light constriction diameter (diameter of the opening 105a) of the insulating layer 105 is, for example, 3 to 10 μm. Examples of the planar shape of the opening 105a include circular, elliptical, I-shaped, O-shaped (ring-shaped), and polygonal. It is preferable that the insulating layer 105 be placed at or near the position of the standing wave node generated in the resonator.

[0037] (Transparent conductive film) The transparent conductive film 106 enhances the hole injection efficiency into the active layer 103 and functions as a buffer layer to prevent leakage. The transparent conductive film 106 is made of, for example, ITO, ITiO, AZO, ZnO, SnO, SnO2, SnO3, TiO, TiO2, graphene, etc.

[0038] (Second Reflector) The plane mirror as the second reflector 107 of the second reflection structure RS2 is made of, for example, a dielectric multilayer reflector. This dielectric multilayer reflector has low light absorption, high reflectivity and insulating properties. The multilayer reflector is also called a distributed Bragg reflector (DBR). This dielectric multilayer reflector has a structure in which high refractive index layers and low refractive index layers with different refractive indices are alternately stacked with an optical thickness of 1 / 4 wavelength of the emission wavelength of the active layer 103. The dielectric multilayer reflector is preferably made of a material containing at least one of, for example, SiO2, TiO2, Ta2O5, SiN, a-Si, MgF2 and CaF2. In this dielectric multilayer reflector, the thickness of each refractive index layer is, for example, 127 nm, and the number of pairs is, for example, less than 7.5 pairs. The plane mirror serving as the second reflecting mirror 107 has a planar shape, such as a circle or an ellipse.

[0039] (Anode Electrode) The anode electrode 109 is composed of at least one metal (including alloys) selected from the group consisting of, for example, Au, Ag, Pd, Pt, Ni, Ti, V, W, Cr, Al, Cu, Zn, Sn, and In. If the anode electrode 109 has a layered structure, it is composed of materials such as Ti / Au, Ti / Al, Ti / Al / Au, Ti / Pt / Au, Ni / Au, Ni / Au / Pt, Ni / Pt, Pd / Pt, Ag / Pd, etc. The anode electrode 109 is connected to the anode terminal of the laser driver.

[0040] (Cathode Electrode) The cathode electrode 111 is composed of at least one metal (including alloys) selected from the group consisting of, for example, Au, Ag, Pd, Pt, Ni, Ti, V, W, Cr, Al, Cu, Zn, Sn, and In. When the cathode electrode 111 has a laminated structure, it is composed of materials such as, for example, Ti / Au, Ti / Al, Ti / Al / Au, Ti / Pt / Au, Ni / Au, Ni / Au / Pt, Ni / Pt, Pd / Pt, Ag / Pd, etc. The cathode electrode 111 is connected to the cathode terminal of the laser driver.

[0041] (Details of the First Reflection Structure) As an example, the first reflection structure RS1 has a reflectance distribution in the in-plane direction (the direction along the first convex surface 101a). Specifically, the first reflection structure RS1 has different first reflectance, which is the reflectance of the central part, and second reflectance, which is the reflectance of the peripheral part. Here, the second reflectance is lower than the first reflectance. That is, the first reflection structure RS1 has a high reflectance region HRA in the central part and a low reflectance region LRA in the peripheral part (see FIG. 2).

[0042] [[ID='8']] The diameter of the central part of the first reflection structure RS1 coincides with the beam diameter 3σ (effective beam diameter) of the laser beam, which is the emitted light.

[0043] Here, when the resonator length is L, the radius of curvature of the first convex surface 101a is R, the oscillation wavelength is λ, and the average refractive index of the region between the first convex surface 101a and the second reflection structure RS2 (specifically, the second mirror 107) is n, the diameter (for example, diameter) of the central part of the first reflection structure RS1 is 3[(λ / πn)[LR 2 / (R - L)] 1 / 2 1 / 2 is.

[0044] The central part of the first reflection structure RS1, as an example, overlaps with the light-emitting region 103a of the active layer 103 (the region corresponding to the opening 105a of the insulating layer 105) in a plan view.

[0045] ​The first convex surface 101a has a first roughness (e.g., mean square roughness) in the central part 101a1 and a second roughness (e.g., mean square roughness) in the peripheral part 101a2, which is different. Here, the second roughness is higher than the first roughness. Therefore, the central part 101a1 of the first convex surface 101a is also called the "low roughness region," and the peripheral part 101a2 (the part in Figure 1 where many protrusions p are formed) is also called the "high roughness region." More specifically, the low roughness region is a smooth surface or a surface with small etching residues (organic matter, metal, etc.) that do not affect oscillation (little optical loss due to scattering). The high roughness region is a surface with large etching residues (organic matter, metal, etc.) that affect oscillation (little optical loss due to scattering). Due to this difference in roughness, the reflectivity of the peripheral part of the interface between the first convex surface 101a and the concave surface 108b is lower than the reflectivity of the central part. On the other hand, the concave mirror serving as the first reflector 108 has a uniform reflectivity in the in-plane direction (the direction along the first convex surface 101a). As a result, the reflectivity of the peripheral part of the first reflective structure RS1 is lower than that of the central part. Furthermore, the reflectivity of the central part of the first reflective structure RS1 is slightly higher than that of the second reflective structure RS2 (more specifically, the plane mirror serving as the second reflector 107). In addition, a difference in roughness occurs in the central and peripheral parts of the second convex surface 108a, corresponding to the difference in roughness between the central part 101a1 and the peripheral part 101a2 of the first convex surface 101a, and a reflectivity distribution (for example, high reflectivity in the central part and low reflectivity in the peripheral part) can occur at the interface between the second convex surface 108a and the air. Roughness, in a broad sense, refers to surface roughness (the magnitude of surface irregularities).

[0046] In other words, in the surface-emitting laser 10, the first reflective structure RS1 is configured such that the gain necessary for oscillation is obtained in the central part, but the gain necessary for oscillation is not obtained in the peripheral part. The surface-emitting laser 10 controls the transverse modes by this reflectivity distribution.

[0047] It is known that the reflectance of the peripheral part of the first reflective structure RS1 decreases as the roughness (RMS) of the first convex surface 101a increases. In order to raise the reflectance of the central part of the first reflective structure RS1 to a level in which the gain necessary for oscillation can be obtained (for example, 99% or more at a wavelength of 455 nm), the first roughness (for example, mean square roughness), which is the roughness of the central part 101a1 of the first convex surface 101a, is preferably 1.0 nm or less, more preferably 0.5 nm or less, and even more preferably 0.1 nm or less. On the other hand, in order to lower the reflectance of the peripheral part of the first reflective structure RS1 to a level in which the gain necessary for oscillation cannot be obtained (for example, less than 99% at a wavelength of 455 nm), the second roughness (for example, mean square roughness), which is the roughness of the peripheral part 101a2 of the first convex surface 101a, is preferably 1.5 nm or more, and more preferably 2.0 nm or more. In Figure 1, the area on the back surface (bottom surface) of the substrate 101 corresponding to the electrode mounting portion 101b is also a high-roughness area, but the protrusions are not shown (the same applies to other cross-sectional views).

[0048] Figure 3A is a schematic cross-sectional view of the surface-emitting laser C1 according to Comparative Example 1 (however, the concave mirror is not shown). The surface-emitting laser C1 (surface emission type) according to Comparative Example 1 shown in Figure 3A has the same configuration as the surface-emitting laser 10 according to Example 1, except that the etching residue on the convex surface of the lens-shaped portion is removed and no difference in roughness is provided on the convex surface. In the surface-emitting laser C1, single-mode (specifically single transverse mode, hereinafter the same) is easily emitted in the center of the resonator, and multi-mode (specifically multi-transverse mode, hereinafter the same) is easily emitted in the peripheral part of the resonator, and both single-mode and multi-mode light are extracted from the aperture of the ring electrode on the emission side.

[0049] Figure 3B is a schematic cross-sectional view of the surface-emitting laser C2 according to Comparative Example 2 (however, the concave mirror is not shown). The surface-emitting laser C2 (surface-emitting type) according to Comparative Example 2 shown in Figure 3B has the same configuration as the surface-emitting laser C1 according to Comparative Example 1, except that the inner diameter of the ring electrode on the emission side is small. In the surface-emitting laser C2, multimode light (light with a bimodal intensity distribution, the same applies hereinafter) can be blocked at the inner circumference of the ring electrode on the emission side, and only single-mode light (light with a unimodal intensity distribution, the same applies hereinafter) can be extracted.

[0050] Figure 4 is a schematic cross-sectional view of the surface-emitting laser 10 according to Example 1. In the surface-emitting laser 10, the convex surface in the center of the resonator is smooth or only has small etching residue attached, so there is no or almost no loss due to light scattering and single-mode oscillation occurs. At the other hand, the convex surface in the peripheral part of the resonator has large etching residue attached, causing surface roughness and resulting in greater loss due to light scattering, thus suppressing multi-mode oscillation and making it possible to extract only single-mode light. In the surface-emitting laser 10, since the generation of multi-mode light is suppressed, it is not necessary to reduce the inner diameter of the output ring electrode in order to extract only single-mode light. This makes it possible to suppress vignetting of single-mode light at the ring electrode.

[0051] Furthermore, since the interface between the substrate and the concave mirror is an interface between dissimilar materials with different coefficients of thermal expansion, there is a concern that the concave mirror may peel off if, for example, the surface-emitting lasers C1 and C2 according to Comparative Examples 1 and 2 (see Figures 3A and 3B) have a convex surface that does not have a high-roughness region. On the other hand, in the surface-emitting laser 10 according to Example 1, the etching residue of at least the high-roughness region of the first convex surface 101a bites into the concave surface 108b of the concave mirror which serves as the first reflecting mirror 108, providing an anchoring effect. This improves the adhesion between the substrate 101 and the concave mirror, suppressing the peeling of the concave mirror from the substrate 101 during manufacturing, mounting, and use of the surface-emitting laser 10.

[0052] ≪Operation of the Surface-Emitting Laser≫ The operation of the surface-emitting laser 10 will be described below. In the surface-emitting laser 10, when a driving voltage is applied between the anode electrode 109 and the cathode electrode 111 by the laser driver, current flows into the resonator from the anode side of the laser driver through the anode electrode 109. The current that flows into the resonator is narrowed by the insulating layer 105 via the transparent conductive film 106 and injected into the active layer 103 via the second cladding layer 104. At this time, the active layer 103 emits light, and the light travels back and forth between the central part of the first reflective structure RS1 and the second reflective structure RS2, amplified by the active layer 103 and narrowed by the insulating layer 105 (during this time, the light is focused and reflected near the active layer 103 at the central part of the first reflective structure RS1, and then reflected back towards the active layer 103 as parallel light or weakly diffused light at the second reflective structure RS2). When the oscillation conditions are met, it is emitted from the second reflective structure RS2 as single-mode light. On the other hand, light emitted from the active layer 103 and incident on the peripheral part of the first reflective structure RS1 is lost due to scattering and does not result in multi-mode oscillation. The current injected into the active layer 103 flows out from the cathode electrode 111 to the cathode side of the laser driver via the first cladding layer 102 and the substrate 101 in that order.

[0053] <<Manufacturing Method for Surface-Emitting Lasers>> Below, an example of a manufacturing method for surface-emitting lasers 10 will be explained with reference to the flowchart in Figure 5.

[0054] In the first step S1, a laminate is generated (see Figure 6A). Specifically, a first cladding layer 102, an active layer 103, and a second cladding layer 104 are grown in this order on a substrate 101 (e.g., an n-GaN substrate) in a growth chamber using metal-organic vapor deposition (MOCVD) or molecular beam epitaxy (MBE) to generate a laminate.

[0055] In the next step S2, the electrode mounting portion 101b is formed (see Figure 6B). Specifically, a resist pattern is formed on the laminate to cover the areas other than where the electrode mounting portion 101b is formed, and the laminate is etched using this resist pattern as a mask. During this process, etching is carried out until the etching bottom surface is located within the substrate 101. As a result, a stepped portion is formed on the substrate 101 with the electrode mounting portion 101b as the bottom surface.

[0056] In the next step S3, an insulating layer 105 is formed. Specifically, first, an insulating layer 105 is deposited on the entire surface of the laminate on which the electrode mounting portion 101b is formed (see Figure 7A). Then, openings 105a are formed in the insulating layer 105 and the electrode mounting portion 101b is exposed by photolithography and etching (see Figure 7B).

[0057] In the next step S4, a transparent conductive film 106 is formed (see Figure 8A). Specifically, first, the transparent conductive film 106 is deposited over the entire surface by, for example, vacuum deposition or sputtering. Then, the transparent conductive film 106 on the periphery of the insulating layer 105 and the transparent conductive film 106 on the electrode installation area 101b are removed by photolithography and etching.

[0058] In the next step S5, the anode electrode 109 and cathode electrode 111 are formed (see Figure 8B). Specifically, for example, using the lift-off method, the anode electrode 109 is formed in a circumferential shape (e.g., a ring shape) that spans the outer periphery of the insulating layer 105 and the peripheral area of ​​the transparent conductive film 106, and the cathode electrode 111 is formed on the electrode mounting portion 101b. For the deposition of the electrode material at this time, for example, vacuum deposition or sputtering is used.

[0059] In the next step S6, a plane mirror is formed as the second reflecting mirror 107 (see Figure 9A). Specifically, first, a dielectric multilayer film, which is the material for the plane mirror, is deposited over the entire surface by, for example, vacuum deposition, sputtering, or CVD. Next, a resist pattern is formed that covers only the dielectric multilayer film that will become the plane mirror, and by etching using this resist pattern as a mask, only the dielectric multilayer film that will become the plane mirror remains.

[0060] In the next step S7, a lens-shaped portion having the first convex surface 101a is formed. Specifically, first, a resist R is applied to the area on the back surface of the substrate 101 where the lens-shaped portion will be formed by photolithography. Next, the resist R is formed into a substantially hemispherical shape by reflow at a temperature of, for example, 200°C (see Figure 9B). Then, etching is performed using the substantially hemispherical resist R as a mask (see Figure 10A) to form the lens-shaped portion (see Figure 10B). At this time, the etching time (more specifically, the plasma irradiation time) is longer in the area where the peripheral part of the lens-shaped portion is formed and in the area on the back surface of the substrate 101 where the peripheral part of the first convex surface 101a is formed than in the area where the central part of the lens-shaped portion is formed. As a result, a large amount of etching residue adheres to the peripheral part 101a2 of the first convex surface 101a and to the area on the back surface of the substrate 101 where the first convex surface 101a is formed. In this process, the etching time can be controlled by adjusting the etching conditions (e.g., etching rate), thereby controlling the size of the etching residue in the central portion 101a1 and the peripheral portion 101a2 of the first convex surface 101a. After that, the resist R is removed (see Figure 11A).

[0061] In the final step S8, a concave mirror is formed as the first reflecting mirror 108 (see Figure 11B). Specifically, first, a dielectric multilayer film, which is the material for the concave mirror, is deposited on the entire back surface of the substrate 101 by, for example, vacuum deposition, sputtering, or CVD. Next, photolithography and etching are used to leave only the dielectric multilayer film on the optical waveguide. As a result, a concave mirror with a shape following the first convex surface 101a is formed. This provides an anchoring effect, suppressing the peeling of the concave mirror. After that, the surface-emitting laser 10 is mounted on a package, for example. More specifically, the surface-emitting laser 10 is soldered to the package with the concave mirror side facing it. At this time, the anchoring effect provided by the large etching residue adhering to the area around the region where the concave mirror is formed on the first convex surface 101a and the area around the first convex surface 101a on the back surface of the substrate 101 makes it possible to suppress peeling (detachment) from the package.

[0062] <<Effects of Surface-Emitting Lasers>> The effects of the surface-emitting laser 10 according to Example 1 of one embodiment of this technology will be described below.

[0063] The surface-emitting laser 10 comprises a first reflective structure RS1, a second reflective structure RS2, and an intermediate structure MS containing an active layer 103 sandwiched between the first reflective structure RS1 and the second reflective structure RS2. The first reflective structure RS1 has at least one (for example, more) convex surfaces that are convex on the side opposite to the second reflective structure RS2, and has a reflectance distribution in the in-plane direction.

[0064] In the surface-emitting laser 10, the first reflective structure RS1 has at least one convex surface that is convex on the side opposite to the second reflective structure RS2, and has a reflectivity distribution in the in-plane direction. Therefore, it is possible to provide a surface-emitting laser that can obtain the gain necessary for oscillation regardless of the resonator length and can control the transverse modes.

[0065] The first reflective structure RS1 has a first reflectance, which is the reflectance of the central part, and a second reflectance, which is the reflectance of the peripheral part, which are different. This makes it possible to control both single-mode and multi-mode.

[0066] The active layer 103 has a light-emitting region 103a, and the central part of the first reflective structure RS1 overlaps with the light-emitting region 103a in a plan view. This ensures that single-mode oscillation can be reliably achieved.

[0067] The second reflectance is lower than the first reflectance. This allows for single-mode oscillation while suppressing multi-mode oscillation.

[0068] The first convex surface 101a has a first roughness, which is the roughness of the central part, and a second roughness, which is the roughness of the peripheral part. This allows, for example, the difference in the size of the etching residue generated when forming the lens-shaped portion having the first convex surface 101a between the central and peripheral parts of the first convex surface 101a to be used to create a difference in roughness. In other words, a dedicated process for creating the difference in roughness is not required. Furthermore, there is no need to remove the etching residue.

[0069] The second roughness is higher than the first roughness. This allows for single-mode oscillation while suppressing multi-mode oscillation, all while minimizing the complexity of the manufacturing process.

[0070] The first reflective structure RS1 has a first convex surface 101a and a second convex surface 108a, which is located on the opposite side of the first convex surface 101a from the second reflective structure RS2 side. This allows diffraction loss to be sufficiently reduced by lateral optical field confinement.

[0071] The first reflective structure RS1 includes a concave mirror as the first reflecting mirror 108, which has a concave surface 108b along the first convex surface 101a on the side of the first convex surface 101a, and a second convex surface 108a on the side opposite to the first convex surface 101a. This allows the first convex surface 101a to be used as a base for the concave mirror, and the peeling of the concave mirror can be suppressed by the anchoring effect of the high roughness region of the first convex surface 101a.

[0072] The intermediate structure MS includes a portion of the substrate 101 positioned on the first reflective structure RS1 side of the active layer 103, and the first convex surface 101a is at least a portion (for example, a part) of the concave mirror side surface of the substrate 101. This allows at least a portion (for example, a part) of the concave mirror side surface of the substrate 101 to be used to generate the in-plane reflectance distribution of the first reflective structure RS1.

[0073] When the resonator length is L, the radius of curvature of the first convex surface 101a is R, the oscillation wavelength is λ, and the average refractive index of the region between the first convex surface 101a and the second reflective structure RS2 is n, the diameter of the central part of the first convex surface 101a is 3[(λ / πn)[LR] 2 (RL)] 1 / 2 ] 1 / 2 This is preferable. This allows only single-mode light with a beam diameter of 3σ (effective beam diameter) to be emitted, that is, only high-quality single-mode light with a beam diameter of 3σ to be emitted.

[0074] Both the first and second reflective structures RS1 and RS2 include a dielectric multilayer reflecting mirror. This makes it possible to obtain high reflectivity with a small number of layers in each reflective structure.

[0075] The intermediate structure MS is made of a group III-V compound semiconductor, and this group III-V compound semiconductor is a GaN-based compound semiconductor. This allows the oscillation wavelength to be, for example, 370 nm to 650 nm.

[0076] <2. Surface-emitting laser according to Example 2 of one embodiment of the present technology> Hereinafter, a surface-emitting laser according to Example 2 of one embodiment of the present technology will be described with reference to the drawings. Figure 12 is a cross-sectional view of the surface-emitting laser 20 according to Example 2 of one embodiment of the present technology.

[0077] As shown in Figure 12, the surface-emitting laser 20 has the same configuration as the surface-emitting laser 10 according to Embodiment 1, except that it is a back-side emission type. In the surface-emitting laser 20, the reflectance of the second reflective structure RS2 is higher than the reflectance of the central part of the first reflective structure RS1.

[0078] The surface-emitting laser 20 provides a back-side emission type VCSEL that exhibits the same effects as the surface-emitting laser 10 according to Example 1.

[0079] <3. Surface-emitting laser according to Example 3 of one embodiment of the present technology> Hereinafter, a surface-emitting laser according to Example 3 of one embodiment of the present technology will be described with reference to the drawings. Figure 13 is a cross-sectional view of the surface-emitting laser 30 according to Example 3 of one embodiment of the present technology.

[0080] As shown in Figure 13, the surface-emitting laser 30 has the same configuration as the surface-emitting laser 20 according to Example 2, except that the anode electrode 109 constitutes part of the second reflection structure RS2.

[0081] In the surface-emitting laser 30, the anode electrode 109 is positioned to cover a plane mirror acting as a second reflector 107, and the portion covering the upper surface of the plane mirror functions as a metallic reflector. In other words, the second reflective structure RS2 here constitutes a hybrid mirror including a plane mirror and the metallic reflector.

[0082] The surface-emitting laser 30 provides the same effects as the surface-emitting laser 20 according to Example 2, and because the anode electrode 109 can be made larger in area, the resistance (e.g., contact resistance) between the anode electrode 109 and the anode terminal of the laser driver can be reduced.

[0083] <4. Surface-emitting laser according to Example 4 of one embodiment of the present technology> Hereinafter, a surface-emitting laser according to Example 4 of one embodiment of the present technology will be described with reference to the drawings. Figure 14 is a cross-sectional view of the surface-emitting laser 40 according to Example 4 of one embodiment of the present technology.

[0084] The surface-emitting laser 40 has the same configuration as the surface-emitting laser 10 according to Embodiment 1, except that, as shown in Figure 14, a concave mirror as the first reflector 108 is provided over the entire area of ​​the first convex surface 101a on the back surface of the substrate 101 and in the area surrounding the first convex surface 101a.

[0085] The surface-emitting laser 40 provides the same effects as the surface-emitting laser 10 in Example 1, but with a wider anchoring effect, thus more reliably suppressing the peeling of the concave mirror from the substrate 101.

[0086] Furthermore, the surface-emitting laser 40 can be configured as either a front-emitting or back-emitting type by appropriately setting the relative reflectances of the first and second reflective structures RS1 and RS2.

[0087] <5. Surface-emitting laser according to Example 5 of one embodiment of the present technology> Hereinafter, a surface-emitting laser according to Example 5 of one embodiment of the present technology will be described with reference to the drawings. Figure 15 is a cross-sectional view of the surface-emitting laser 50 according to Example 5 of one embodiment of the present technology.

[0088] As shown in Figure 15, the surface-emitting laser 50 has a configuration that is generally the same as the surface-emitting laser 10 according to Embodiment 1, except that the first reflective structure RS1 includes a plane mirror as a first reflector 108 and a substrate 101 positioned on the opposite side of the plane mirror from the second reflective structure RS2, and the substrate 101 has a first convex surface 101a on the opposite side from the second reflective structure RS2.

[0089] In the surface-emitting laser 50, as an example, a plane mirror as the first reflector 108 is placed between the substrate 101 and the first cladding layer 102. The plane mirror as the first reflector 108 is, as an example, an n-type semiconductor multilayer reflector (e.g., an n-GaN / n-AlGaN multilayer reflector). The plane mirror as the second reflector 107 is, as an example, a p-type semiconductor multilayer reflector (e.g., a p-GaN / p-AlGaN multilayer reflector). The plane mirror as the second reflector 107 is placed between the second cladding layer 104 and the central part of the insulating layer 105 and the transparent conductive film 106. The reflectance of the plane mirror as the first reflector 108 is set to be slightly higher than the reflectance of the plane mirror as the second reflector 107. The transparent conductive film 106 has its central portion located within the opening 105a of the insulating layer 105 and in contact with the plane mirror serving as the second reflecting mirror 107, while its peripheral portion is located on the insulating layer 105. A circumferential (for example, ring-shaped) anode electrode 109 is provided on the peripheral portion of the transparent conductive film 106.

[0090] Below, an example of a manufacturing method for the surface-emitting laser 50 will be explained with reference to the flowchart in Figure 16.

[0091] In the first step S11, a laminate is generated (see Figure 17A). Specifically, using metal-organic vapor deposition (MOCVD) or molecular beam epitaxy (MBE), an n-type semiconductor multilayer reflector as the first reflector 108, a first cladding layer 102, an active layer 103, a second cladding layer 104, and a p-type semiconductor multilayer reflector as the second reflector 107 are grown in this order on a substrate 101 (e.g., an n-GaN substrate) in a growth chamber to generate a laminate.

[0092] In the next step S12, the electrode mounting portion 101b is formed (see Figure 17B). Specifically, a resist pattern is formed on the laminate to cover the areas other than where the electrode mounting portion 101b is formed, and the laminate is etched using this resist pattern as a mask. During this process, etching is carried out until the etching bottom surface is located within the substrate 101. As a result, a stepped portion is formed on the substrate 101 with the electrode mounting portion 101b as the bottom surface.

[0093] In the next step S13, an insulating layer 105 is formed. Specifically, first, an insulating layer 105 is deposited on the entire surface of the laminate on which the electrode mounting portion 101b is formed (see Figure 18A). Then, openings 105a are formed in the insulating layer 105 and the electrode mounting portion 101b is exposed by photolithography and etching (see Figure 18B).

[0094] In the next step S14, a transparent conductive film 106 is formed (see Figure 19A). Specifically, first, a transparent conductive film 106 is formed on the entire surface of the laminate on which the insulating layer 105 has been formed by, for example, vacuum deposition or sputtering. Then, the transparent conductive film 106 on the electrode installation portion 101b is removed by photolithography and etching.

[0095] In the next step S15, the anode electrode 109 and cathode electrode 111 are formed (see Figure 19B). Specifically, for example, the anode electrode 109 is formed in a circumferential manner (e.g., a ring shape) on the periphery of the transparent conductive film 106 using the lift-off method, and the cathode electrode 111 is formed on the electrode mounting portion 101b. For the deposition of the electrode material at this time, for example, vacuum deposition or sputtering is used.

[0096] In the final step S16, a lens-shaped portion having the first convex surface 101a is formed. Specifically, first, a resist R is formed on the back surface of the substrate 101 in the area where the lens-shaped portion will be formed by photolithography. Next, the resist R is formed into a substantially hemispherical shape by reflow at a temperature of, for example, 200°C (see Figure 20A). Then, etching is performed using the substantially hemispherical resist R as a mask (see Figure 20B) to form the lens-shaped portion (see Figure 21A). At this time, the etching time (more specifically, the plasma irradiation time) is longer in the region where the peripheral portion of the lens-shaped portion is formed and in the region on the back surface of the substrate 101 where the peripheral portion of the first convex surface 101a is formed than in the region where the central portion of the lens-shaped portion is formed. As a result, a large amount of etching residue adheres to the peripheral portion 101a2 of the first convex surface 101a and to the region on the back surface of the substrate 101 where the first convex surface 101a is formed. In this process, the etching time can be controlled by adjusting the etching conditions (e.g., etching rate), thereby controlling the size of the etching residue in the central part 101a1 and the peripheral part 101a2 of the first convex surface 101a. After that, the resist R is removed (see Figure 21B). The surface-emitting laser 10 manufactured in this manner is mounted, for example, in a package. More specifically, the back surface of the substrate 101 of the surface-emitting laser 10 is soldered to the package. At this time, the anchoring effect provided by the large etching residue adhering to the back surface of the substrate 101 makes it possible to suppress peeling (detachment) from the package.

[0097] The surface-emitting laser 50 provides the same effects as the surface-emitting laser 10 in Example 1, and offers superior productivity because the resonator can be generated solely by epitaxial growth.

[0098] <6. Surface-emitting laser according to Example 6 of one embodiment of the present technology> Hereinafter, a surface-emitting laser according to Example 6 of one embodiment of the present technology will be described with reference to the drawings. Figure 22 is a cross-sectional view of the surface-emitting laser 60 according to Example 6 of one embodiment of the present technology.

[0099] As shown in Figure 22, the surface-emitting laser 60 has a configuration that is generally the same as the surface-emitting laser 50 according to Embodiment 5, except that it is a back-side emission type.

[0100] In the surface-emitting laser 60, the reflectivity of the second reflective structure RS2 is set slightly higher than that of the first reflective structure RS1. The surface-emitting laser 60 has an anti-reflective coating 112 on the back surface of the substrate 101. The peeling of the anti-reflective coating 112 is suppressed by the anchoring effect of the high-roughness region on the back surface of the substrate 101. The anti-reflective coating 112 is useful for improving light utilization efficiency, but it is not essential.

[0101] The surface-emitting laser 60 provides a back-side emission type VCSEL that achieves the same effects as the surface-emitting laser 50 according to Example 5.

[0102] <7. Surface-emitting laser according to Example 7 of one embodiment of the present technology> Hereinafter, a surface-emitting laser according to Example 7 of one embodiment of the present technology will be described with reference to the drawings. Figure 23 is a cross-sectional view of the surface-emitting laser 70 according to Example 7 of one embodiment of the present technology.

[0103] As shown in Figure 23, the surface-emitting laser 70 has a configuration that is generally the same as the surface-emitting laser 10 according to Embodiment 1, except that the surface-emitting laser 70 has irregularities DP provided throughout the entire circumferential direction in the peripheral portion 101a2 of the first convex surface 101a and the region surrounding the first convex surface 101a on the back surface of the substrate 101. Hereinafter, the region on the back surface of the substrate 101 where the irregularities DP are provided will also be referred to as the "irregular region".

[0104] In the surface-emitting laser 70, the surface irregularities DP are formed by the peripheral portion 101a2 of the first convex surface 101a, a plurality of convex portions P provided in the region surrounding the first convex surface 101a, and recesses D between the convex portions P.

[0105] In the surface-emitting laser 70, the same roughness difference as in the surface-emitting laser 10 is not provided between the central portion 101a1 and the peripheral portion 101a2 of the first convex surface 101a, but it may be provided.

[0106] In the surface-emitting laser 70, the first reflection structure RS1 has a smooth surface at the central part 101a1 of the first convex surface 101a, where no uneven DP is provided, allowing single-mode oscillation with little to no loss due to light scattering. In the surface-emitting laser 70, the peripheral part 101a2 of the first convex surface 101a has a large loss due to light scattering at the uneven DP, suppressing multi-mode oscillation. The size of the uneven DP is preferably 1.5 nm or more, and more preferably 2.0 nm or more, similar to the second roughness described above.

[0107] In the surface-emitting laser 70, the peeling of the concave mirror is suppressed by the anchoring effect of the uneven region on the back surface of the substrate 101.

[0108] Below, an example of a manufacturing method for the surface-emitting laser 70 will be explained with reference to the flowchart in Figure 24.

[0109] In the first step S21, a laminate is generated (see Figure 6A). Specifically, a first cladding layer 102, an active layer 103, and a second cladding layer 104 are grown in this order on a substrate 101 (e.g., an n-GaN substrate) in a growth chamber using metal-organic vapor deposition (MOCVD) or molecular beam epitaxy (MBE) to generate a laminate.

[0110] In the next step S22, the electrode mounting portion 101b is formed (see Figure 6B). Specifically, a resist pattern is formed on the laminate to cover the areas other than where the electrode mounting portion 101b is formed, and the laminate is etched using this resist pattern as a mask. During this process, etching is carried out until the etching bottom surface is located within the substrate 101. As a result, a stepped portion is formed on the substrate 101 with the electrode mounting portion 101b as the bottom surface.

[0111] In the next step S23, an insulating layer 105 is formed. Specifically, first, an insulating layer 105 is deposited on the entire surface of the laminate on which the electrode mounting portion 101b is formed (see Figure 7A). Then, openings 105a are formed in the insulating layer 105 and the electrode mounting portion 101b is exposed by photolithography and etching (see Figure 7B).

[0112] In the next step S24, a transparent conductive film 106 is formed (see Figure 8A). Specifically, first, the transparent conductive film 106 is deposited over the entire surface by, for example, vacuum deposition or sputtering. Then, the transparent conductive film 106 on the periphery of the insulating layer 105 and the transparent conductive film 106 on the electrode installation portion 101b are removed by photolithography and etching.

[0113] In the next step S25, the anode electrode 109 and cathode electrode 111 are formed (see Figure 8B). Specifically, for example, using the lift-off method, the anode electrode 109 is formed in a circumferential shape (e.g., a ring shape) that spans the outer periphery of the insulating layer 105 and the peripheral area of ​​the transparent conductive film 106, and the cathode electrode 111 is formed on the electrode mounting portion 101b. For the deposition of the electrode material at this time, for example, vacuum deposition or sputtering is used.

[0114] In the next step S26, a plane mirror is formed as the second reflecting mirror 107 (see Figure 9A). Specifically, first, a dielectric multilayer film, which is the material for the plane mirror, is deposited over the entire surface by, for example, vacuum deposition, sputtering, or CVD. Next, a resist pattern is formed that covers only the dielectric multilayer film that will become the plane mirror, and by etching using this resist pattern as a mask, only the dielectric multilayer film that will become the plane mirror remains.

[0115] In the next step S27, a lens-shaped portion having a first convex surface 101a is formed. Specifically, first, a resist R is formed on the back surface of the substrate 101 in the area where the lens-shaped portion will be formed by photolithography. Next, the resist R is formed into a substantially hemispherical shape by reflow at a temperature of, for example, 200°C (see Figure 9B). Then, etching is performed using the substantially hemispherical resist R as a mask (see Figure 10A) to form the lens-shaped portion (see Figure 10B). After this, the etching residue and resist R adhering to the back surface of the substrate 101 are removed (see Figure 25A).

[0116] In the next step S28, the uneven surface DP is formed (see Figure 25B). Specifically, multiple protrusions P are patterned on the peripheral area 101a2 of the first convex surface 101a and the surrounding area of ​​the first convex surface 101a on the back surface of the substrate 101 by photolithography and etching.

[0117] In the final step S29, a concave mirror is formed as the first reflecting mirror 108 (see Figure 26). Specifically, first, a dielectric multilayer film, which is the material for the concave mirror, is deposited on the entire back surface of the substrate 101 by, for example, vacuum deposition, sputtering, or CVD. Next, photolithography and etching are used to leave only the dielectric multilayer film on the optical waveguide. As a result, a concave mirror with a shape that follows the first convex surface 101a is formed. This provides an anchoring effect due to the irregularities formed on the peripheral portion 101a2 of the first convex surface 101a, suppressing the peeling of the concave mirror. The surface-emitting laser 70 manufactured in this manner is mounted, for example, in a package. More specifically, the surface-emitting laser 70 has the concave mirror side soldered to the package. At this time, the anchoring effect provided by the irregularities formed in the area surrounding the concave mirror of the first convex surface 101a and in the area surrounding the first convex surface 101a on the back surface of the substrate 101 makes it possible to suppress the peeling (detachment) of the surface-emitting laser 70 from the package.

[0118] Although the surface-emitting laser 70 requires the formation of uneven surfaces DP on the back surface of the substrate 101, it achieves generally the same effects as the surface-emitting laser 10 according to Example 1.

[0119] Furthermore, the surface-emitting laser 70 can be configured as either a front-emitting or back-emitting type by appropriately setting the relative reflectances of the first and second reflective structures RS1 and RS2.

[0120] <8. Surface-emitting laser according to Example 8 of one embodiment of the present technology> Hereinafter, a surface-emitting laser according to Example 8 of one embodiment of the present technology will be described with reference to the drawings. Figure 27 is a cross-sectional view of the surface-emitting laser 80 according to Example 8 of one embodiment of the present technology.

[0121] The surface-emitting laser 80 has the same configuration as the surface-emitting laser 70 according to Embodiment 7 (see Figure 23), except that a concave mirror as the first reflector 108 is provided over the entire area of ​​the first convex surface 101a on the back surface of the substrate 101 and in the area surrounding the first convex surface 101a, as shown in Figure 27.

[0122] The surface-emitting laser 80 provides the same effects as the surface-emitting laser 70 in Example 7, but with a wider anchoring effect, thus further suppressing the peeling of the concave mirror from the substrate 101.

[0123] Furthermore, the surface-emitting laser 80 can be configured as either a front-emitting or back-emitting type by appropriately setting the relative reflectances of the first and second reflective structures RS1 and RS2.

[0124] <9. Surface-emitting laser according to Example 9 of one embodiment of the present technology> Hereinafter, a surface-emitting laser according to Example 9 of one embodiment of the present technology will be described with reference to the drawings. Figure 28 is a cross-sectional view of the surface-emitting laser 90 according to Example 9 of one embodiment of the present technology.

[0125] As shown in Figure 28, the surface-emitting laser 90 has the same configuration as the surface-emitting laser 10 according to Embodiment 1, except that the surface-emitting laser 90 has irregularities DP provided over the entire circumferential region in the peripheral portion 101a2 of the first convex surface 101a on the back surface of the substrate 101 and in the region surrounding the first convex surface 101a.

[0126] In the surface-emitting laser 90, the surface irregularities DP are formed by the peripheral portion 101a2 of the first convex surface 101a, a plurality of recesses D provided in the region surrounding the first convex surface 101a, and the protrusions P between the recesses D.

[0127] The surface-emitting laser 90 provides the same effects as the surface-emitting laser 70 in Example 7.

[0128] Furthermore, the surface-emitting laser 90 can be configured as either a front-emitting or back-emitting type by appropriately setting the relative reflectances of the first and second reflective structures RS1 and RS2.

[0129] <10. Surface-emitting laser according to Example 10 of one embodiment of the present technology> Hereinafter, a surface-emitting laser according to Example 10 of one embodiment of the present technology will be described with reference to the drawings. Figure 29 is a cross-sectional view of the surface-emitting laser 100 according to Example 10 of one embodiment of the present technology.

[0130] The surface-emitting laser 100 has the same configuration as the surface-emitting laser 90 according to Embodiment 9 (see Figure 28), except that a concave mirror as a first reflector 108 is provided over the entire area of ​​the first convex surface 101a on the back surface of the substrate 101 and in the area surrounding the first convex surface 101a, as shown in Figure 29.

[0131] The surface-emitting laser 100 provides the same effects as the surface-emitting laser 90 in Example 9, but also allows for a wider anchoring effect, thus further suppressing the peeling of the concave mirror from the substrate 101.

[0132] Furthermore, the surface-emitting laser 100 can be configured as either a surface-emitting or back-emitting type by appropriately setting the relative reflectances of the first and second reflective structures RS1 and RS2.

[0133] <11. Surface-emitting laser according to Example 11 of one embodiment of the present technology> Hereinafter, a surface-emitting laser according to Example 11 of one embodiment of the present technology will be described with reference to the drawings. Figure 30 is a cross-sectional view of the surface-emitting laser 110 according to Example 11 of one embodiment of the present technology.

[0134] As shown in Figure 30, the surface-emitting laser 110 has the same configuration as the surface-emitting laser 50 according to Embodiment 5 (see Figure 15), except that the surface-emitting laser 110 has irregularities DP provided over the entire circumferential region in the peripheral portion 101a2 of the first convex surface 101a on the back surface of the substrate 101 and in the region surrounding the first convex surface 101a.

[0135] In the surface-emitting laser 110, the same roughness difference as in the surface-emitting laser 10 is not provided between the central portion 101a1 and the peripheral portion 101a2 of the first convex surface 101a, but it may be provided.

[0136] In the surface-emitting laser 110, the surface irregularities DP are formed by the peripheral portion 101a2 of the first convex surface 101a, a plurality of convex portions P provided in the region surrounding the first convex surface 101a, and recesses D between the convex portions P.

[0137] The surface-emitting laser 110 provides the same effects as the surface-emitting laser 50 according to Example 5.

[0138] <12. Surface-emitting laser according to Example 12 of one embodiment of the present technology> Hereinafter, a surface-emitting laser according to Example 12 of one embodiment of the present technology will be described with reference to the drawings. Figure 31 is a cross-sectional view of the surface-emitting laser 120 according to Example 12 of one embodiment of the present technology.

[0139] As shown in Figure 31, the surface-emitting laser 120 has a configuration that is generally the same as the surface-emitting laser 110 according to Embodiment 11 (see Figure 30), except that it is a back-side emission type.

[0140] In the surface-emitting laser 120, the same roughness difference as in the surface-emitting laser 10 is not provided between the central portion 101a1 and the peripheral portion 101a2 of the first convex surface 101a, but it may be provided.

[0141] In the surface-emitting laser 120, the reflectivity of the second reflective structure RS2 is set slightly higher than that of the first reflective structure RS1. The surface-emitting laser 120 has an anti-reflective coating 112 on the back surface of the substrate 101. The peeling of the anti-reflective coating 112 is suppressed by the anchoring effect of the uneven regions on the back surface of the substrate 101. Although the anti-reflective coating 112 is useful for improving light utilization efficiency, it is not essential.

[0142] The surface-emitting laser 120 provides a back-side emission type VCSEL that achieves the same effects as the surface-emitting laser 110 according to Example 11.

[0143] <13. Surface-emitting laser according to Example 13 of one embodiment of the present technology> Hereinafter, a surface-emitting laser according to Example 13 of one embodiment of the present technology will be described with reference to the drawings. Figure 32 is a cross-sectional view of the surface-emitting laser 130 according to Example 13 of one embodiment of the present technology.

[0144] The surface-emitting laser 130 has a configuration that is generally the same as the surface-emitting laser 10 according to Embodiment 1 (see Figure 1), except that a thin film 113 is provided in the peripheral portion 101a2 of the first convex surface 101a on the back surface of the substrate 101 and in the region surrounding the first convex surface 101a, as shown in Figure 32.

[0145] In the surface-emitting laser 130, the same roughness difference as in the surface-emitting laser 10 is not provided between the central portion 101a1 and the peripheral portion 101a2 of the first convex surface 101a, but it may be provided.

[0146] The thin film 113 is an oxide film (e.g., GaO) or a chloride film (e.g., GaCl) having an opening 113a at a position corresponding to the central part 101a1 of the first convex surface 101a. A portion of the central part of the concave mirror, which serves as the first reflecting mirror 108, fits into the opening 113a. This provides an anchoring effect and suppresses the peeling of the concave mirror.

[0147] In the surface-emitting laser 130, the first reflective structure RS1 has a significantly reduced reflectivity in the peripheral area where the thin film 113 is provided (low reflectivity region LRA), thus suppressing multimode oscillation. However, in the central area where the thin film 113 is not provided (high reflectivity region HRA), the desired reflectivity can be obtained, allowing for single-mode oscillation.

[0148] Although the surface-emitting laser 130 requires the provision of a thin film 113, it achieves generally the same effects as the surface-emitting laser 10 according to Example 1.

[0149] <14. Surface-emitting laser according to Example 14 of one embodiment of the present technology> Hereinafter, a surface-emitting laser according to Example 14 of one embodiment of the present technology will be described with reference to the drawings. Figure 33 is a cross-sectional view of the surface-emitting laser 140 according to Example 14 of one embodiment of the present technology.

[0150] As shown in Figure 33, the surface-emitting laser 140 has a configuration that is generally the same as the surface-emitting laser 10 according to Example 1 (see Figure 1), except that the first and second convex surfaces 101a and 108a have a reflection direction distribution (more specifically, a radius of curvature distribution) in the in-plane direction.

[0151] In the surface-emitting laser 140, the same roughness difference as in the surface-emitting laser 10 is not provided between the central portion 101a1 and the peripheral portion 101a2 of the first convex surface 101a, but it may be provided.

[0152] The first convex surface 101a has different radii of curvature at its central portion 101a1 and its peripheral portion 101a2. The concave mirror, which is the first reflecting mirror 108 and includes the second convex surface 108a, has a shape that mimics the first convex surface 101a. Hereinafter, the portion of the first convex surface 101a of the concave mirror corresponding to the central portion 101a1 will also be called the "central portion of the concave mirror," and the portion of the first convex surface 101a of the concave mirror corresponding to the peripheral portion 101a2 will also be called the "peripheral portion of the concave mirror."

[0153] Here, the radius of curvature of the central portion 101a1 is larger than the radius of curvature of the peripheral portion 101a2. The radii of curvature of the central portion 101a1 and the central portion of the concave mirror are set to focus the incident light onto the light-emitting region of the active layer 103 or its vicinity, making it possible to generate single-mode oscillation. The radii of curvature of the peripheral portion 101a2 and the peripheral portion of the concave mirror are set to focus the incident light onto a position far away from the light-emitting region of the active layer 103, making it possible to suppress multi-mode oscillation.

[0154] Although the surface-emitting laser 140 cannot achieve an anchoring effect, it produces generally the same effects as the surface-emitting laser 10 in Example 1.

[0155] Furthermore, the surface-emitting laser 140 can be configured as either a surface-emitting or back-emitting type by appropriately setting the relative reflectances of the first and second reflective structures RS1 and RS2.

[0156] <15. Surface-emitting laser according to Example 15 of one embodiment of the present technology> Hereinafter, a surface-emitting laser according to Example 15 of one embodiment of the present technology will be described with reference to the drawings. Figure 34 is a cross-sectional view of a surface-emitting laser 150 according to Example 15 of one embodiment of the present technology.

[0157] As shown in Figure 34, the surface-emitting laser 150 has a configuration that is generally the same as the surface-emitting laser 10 according to Embodiment 1 (see Figure 1), except that the first and second convex surfaces 101a and 108a have a radius of curvature distribution in the in-plane direction.

[0158] In the surface-emitting laser 150, the same roughness difference as in the surface-emitting laser 10 is not provided between the central portion 101a1 and the peripheral portion 101a2 of the first convex surface 101a, but it may be provided.

[0159] The first convex surface 101a has different radii of curvature at its central portion 101a1 and its peripheral portion 101a2. The concave mirror, which is the first reflecting mirror 108 and includes the second convex surface 108a, has a shape that mimics the first convex surface 101a. Hereinafter, the portion of the first convex surface 101a of the concave mirror corresponding to the central portion 101a1 will also be called the "central portion of the concave mirror," and the portion of the first convex surface 101a of the concave mirror corresponding to the peripheral portion 101a2 will also be called the "peripheral portion of the concave mirror."

[0160] Here, the radius of curvature of the central portion 101a1 is smaller than the radius of curvature of the peripheral portion 101a2. The radii of curvature of the central portion 101a1 and the central portion of the concave mirror are set to focus the incident light onto the light-emitting region of the active layer 103 or its vicinity, making it possible to generate single-mode oscillation. The radii of curvature of the peripheral portion 101a2 and the peripheral portion of the concave mirror are set to focus the incident light onto a position far away from the light-emitting region of the active layer 103, making it possible to suppress multi-mode oscillation.

[0161] Although the surface-emitting laser 150 cannot achieve an anchoring effect, it produces effects that are generally similar to those of the surface-emitting laser 10 in Example 1.

[0162] Furthermore, the surface-emitting laser 150 can be configured as either a surface-emitting or back-emitting type by appropriately setting the relative reflectances of the first and second reflective structures RS1 and RS2.

[0163] <16. Surface-emitting laser according to Example 16 of one embodiment of the present technology> Hereinafter, a surface-emitting laser according to Example 16 of one embodiment of the present technology will be described with reference to the drawings. Figure 35 is a cross-sectional view of the surface-emitting laser 160 according to Example 16 of one embodiment of the present technology.

[0164] As shown in Figure 35, the surface-emitting laser 160 has a configuration that is generally the same as the surface-emitting laser 60 according to Embodiment 6 (see Figure 22), except that the first and second convex surfaces 101a and 108a have a radius of curvature distribution in the in-plane direction.

[0165] In the surface-emitting laser 160, the same roughness difference as in the surface-emitting laser 60 is not provided between the central portion 101a1 and the peripheral portion 101a2 of the first convex surface 101a, but it may be provided.

[0166] The first convex surface 101a has different radii of curvature at its central portion 101a1 and at its peripheral portion 101a2.

[0167] Here, the radius of curvature of the central portion 101a1 is smaller than the radius of curvature of the peripheral portion 101a2. The radius of curvature of the central portion 101a1 is set to focus the incident light on or near the light-emitting region of the active layer 103, making it possible to generate single-mode oscillation. The radius of curvature of the peripheral portion 101a2 is set to focus the incident light to a position far away from the light-emitting region of the active layer 103, making it possible to suppress multi-mode oscillation.

[0168] Although the surface-emitting laser 160 cannot achieve an anchoring effect, it produces generally the same effect as the surface-emitting laser 60 in Example 6.

[0169] <16.5. Surface-emitting laser according to Example 16.5 of one embodiment of the present technology> Hereinafter, a surface-emitting laser according to Example 16.5 of one embodiment of the present technology will be described with reference to the drawings. Figure 36 is a cross-sectional view of the surface-emitting laser 165 according to Example 16.5 of one embodiment of the present technology.

[0170] As shown in Figure 36, the surface-emitting laser 165 has a configuration that is generally the same as the surface-emitting laser 160 according to Example 16 (see Figure 35), except that it is a surface-emitting type.

[0171] In the surface-emitting laser 165, the same roughness difference as in the surface-emitting laser 60 is not provided between the central portion 101a1 and the peripheral portion 101a2 of the first convex surface 101a, but it may be provided.

[0172] In the surface-emitting laser 165, the anti-reflective coating 112 is not provided on the back surface of the substrate 101.

[0173] The surface-emitting laser 165 provides a surface-emitting VCSEL that exhibits the same effects as the surface-emitting laser 160 according to Example 16.

[0174] <17. Surface-emitting laser according to Example 17 of one embodiment of the present technology> Hereinafter, a surface-emitting laser according to Example 17 of one embodiment of the present technology will be described with reference to the drawings. Figure 37 is a cross-sectional view of the surface-emitting laser 170 according to Example 17 of one embodiment of the present technology.

[0175] As shown in Figure 37, the surface-emitting laser 170 has a configuration that is generally the same as the surface-emitting laser 60 according to Example 6 (see Figure 22), except that the first and second convex surfaces 101a and 108a have a radius of curvature distribution in the in-plane direction.

[0176] In the surface-emitting laser 170, the same roughness difference as in the surface-emitting laser 60 is not provided between the central portion 101a1 and the peripheral portion 101a2 of the first convex surface 101a, but it may be provided.

[0177] The first convex surface 101a has different radii of curvature at its central portion 101a1 and at its peripheral portion 101a2.

[0178] Here, the radius of curvature of the central portion 101a1 is larger than that of the peripheral portion 101a2. The radius of curvature of the central portion 101a1 is set to focus the incident light onto the light-emitting region of the active layer 103 or its vicinity, making it possible to generate single-mode oscillation. The radius of curvature of the peripheral portion 101a2 is set to focus the incident light onto a position far away from the light-emitting region of the active layer 103, making it possible to suppress multi-mode oscillation.

[0179] Although the surface-emitting laser 170 cannot achieve an anchoring effect, it produces generally the same effect as the surface-emitting laser 60 in Example 6.

[0180] <17.5. Surface-emitting laser according to Example 17.5 of one embodiment of the present technology> Hereinafter, a surface-emitting laser according to Example 17.5 of one embodiment of the present technology will be described with reference to the drawings. Figure 38 is a cross-sectional view of the surface-emitting laser 175 according to Example 17.5 of one embodiment of the present technology.

[0181] As shown in Figure 38, the surface-emitting laser 175 has a configuration that is generally the same as the surface-emitting laser 170 according to Example 17 (see Figure 37), except that it is a surface-emitting type.

[0182] In the surface-emitting laser 175, the same roughness difference as in the surface-emitting laser 60 is not provided between the central portion 101a1 and the peripheral portion 101a2 of the first convex surface 101a, but it may be provided.

[0183] In the surface-emitting laser 175, the anti-reflective coating 112 is not provided on the back surface of the substrate 101.

[0184] The surface-emitting laser 175 provides a surface-emitting VCSEL that exhibits the same effects as the surface-emitting laser 170 according to Example 17.

[0185] <18. Surface-emitting laser according to Example 18 of one embodiment of the present technology> Hereinafter, a surface-emitting laser according to Example 18 of one embodiment of the present technology will be described with reference to the drawings. Figure 39 is a cross-sectional view of the surface-emitting laser 180 according to Example 18 of one embodiment of the present technology.

[0186] As shown in Figure 39, the surface-emitting laser 180 has the same configuration as the surface-emitting laser 10 according to Example 1, except that the first reflection structure RS1 has a metal reflector 114 in addition to the concave mirror which serves as the first reflector 108.

[0187] The metal reflector 114 is provided on the back surface (bottom surface) of the central part (central part of the concave mirror) of the first reflector 108, and together with the concave mirror, it constitutes a hybrid mirror. The metal reflector 114 is made of a metal plating such as Au, Ag, or Al. The bottom surface of the metal reflector 114 has a third convex surface 114a that is convex on the opposite side (downward) from the second reflective structure RS2 side.

[0188] The surface-emitting laser 180 provides the same effects as the surface-emitting laser 10 according to Example 1, and also increases the reflectivity of the central part of the first reflective structure RS1, thereby improving the extraction efficiency (light utilization efficiency) of single-mode light.

[0189] <19. Surface-emitting laser according to Example 19 of one embodiment of the present technology> Hereinafter, a surface-emitting laser according to Example 19 of one embodiment of the present technology will be described with reference to the drawings. Figure 40 is a cross-sectional view of the surface-emitting laser 190 according to Example 19 of one embodiment of the present technology.

[0190] As shown in Figure 40, the surface-emitting laser 190 has a configuration that is generally the same as the surface-emitting laser 10 according to Example 1, except that the number of pairs of high-refractive-index layers and low-refractive-index layers, i.e., the reflectivity, differs between the central part 108A (central part of the concave mirror) and the peripheral part 108B (periphery of the concave mirror) of the first reflecting mirror 108, which is a concave mirror (for example, a dielectric multilayer reflecting mirror).

[0191] In the surface-emitting laser 190, the same roughness difference as in the surface-emitting laser 10 is not provided between the central portion 101a1 and the peripheral portion 101a2 of the first convex surface 101a, but it may be provided.

[0192] In the surface-emitting laser 190, the number of pairs in the center of the concave mirror is greater than the number of pairs in the periphery of the concave mirror. More specifically, the number of pairs in the center of the concave mirror is set to the number of pairs capable of single-mode oscillation, while the number of pairs in the periphery of the concave mirror is set to the number of pairs in which multi-mode oscillation is not possible.

[0193] Although the surface-emitting laser 190 cannot achieve an anchoring effect, it can obtain effects that are generally similar to those of the surface-emitting laser 10 in Example 1.

[0194] Furthermore, the surface-emitting laser 190 can be configured as either a surface-emitting or back-emitting type by appropriately setting the relative reflectances of the first and second reflective structures RS1 and RS2.

[0195] <20. Surface-emitting laser according to Example 20 of one embodiment of the present technology> Hereinafter, a surface-emitting laser according to Example 20 of one embodiment of the present technology will be described with reference to the drawings. Figure 41 is a cross-sectional view of the surface-emitting laser 200 according to Example 20 of one embodiment of the present technology.

[0196] As shown in Figure 41, the surface-emitting laser 200 has a configuration that is generally the same as the surface-emitting laser 10 according to Embodiment 1, except that the first reflecting mirror 108, which is a concave mirror (for example, a dielectric multilayer reflecting mirror), is provided only in the central part 101a1 of the first convex surface 101a.

[0197] In the surface-emitting laser 200, the same roughness difference as in the surface-emitting laser 10 is not provided between the central portion 101a1 and the peripheral portion 101a2 of the first convex surface 101a, but it may be provided.

[0198] In the surface-emitting laser 200, the first reflective structure RS1 has a reflectivity in the central part including the concave mirror that allows single-mode oscillation, and a reflectivity in the peripheral part not including the concave mirror that prevents multi-mode oscillation.

[0199] Although the surface-emitting laser 200 cannot achieve an anchoring effect, it can obtain effects that are generally similar to those of the surface-emitting laser 10 in Example 1.

[0200] Furthermore, the surface-emitting laser 200 can be configured as either a surface-emitting or back-emitting type by appropriately setting the relative reflectances of the first and second reflection structures RS1 and RS2.

[0201] <21. Surface-emitting laser according to Example 21 of one embodiment of the present technology> Hereinafter, a surface-emitting laser according to Example 21 of one embodiment of the present technology will be described with reference to the drawings. Figure 42 is a cross-sectional view of the surface-emitting laser 210 according to Example 21 of one embodiment of the present technology.

[0202] As shown in Figure 42, the surface-emitting laser 210 has a configuration that is generally the same as the surface-emitting laser 10 according to Example 1, except that it does not have an insulating layer 105 and has a circumferential (for example, annular) ion implantation region IIA in plan view.

[0203] In the surface-emitting laser 210, a transparent conductive film 106 is provided in a solid form on the second cladding layer 104, a plane mirror serving as a second reflector 107 is placed on the central part of the transparent conductive film 106, and an anode electrode 109 is placed on the peripheral part of the transparent conductive film 106.

[0204] Ion implantation region IIA defines the light-emitting region (current implantation region) of the active layer 103. Ion implantation region IIA is provided, for example, across the second cladding layer 104, the active layer 103, the first cladding layer 102, and the substrate 101. Examples of ion species in ion implantation region IIA include B ++ , H ++Examples include the following. The ion implantation region IIA has higher resistance (lower carrier conductivity) than the region surrounded by the ion implantation region IIA and has a current constriction function. The current constriction diameter of the ion implantation region IIA (for example, the diameter of the ion implantation region IIA) is, for example, 3 to 10 μm. Examples of the planar shape of the current implantation region include circular, elliptical, I-shaped, O-shaped (ring-shaped), polygonal, etc.

[0205] Although the surface-emitting laser 210 does not have an optical constriction function, it produces generally the same effects as the surface-emitting laser 10 according to Example 1.

[0206] Furthermore, the surface-emitting laser 210 can be configured as either a surface-emitting or back-emitting type by appropriately setting the relative reflectances of the first and second reflective structures RS1 and RS2.

[0207] <22. Surface-emitting laser according to Example 22 of one embodiment of the present technology> Hereinafter, a surface-emitting laser array according to Example 22 of one embodiment of the present technology will be described with reference to the drawings. Figure 43 is a cross-sectional view of a surface-emitting laser array 220 according to Example 22 of one embodiment of the present technology.

[0208] As shown in Figure 43, the surface-emitting laser array 220 comprises a plurality of surface-emitting lasers 10 according to Embodiment 1. The plurality of surface-emitting lasers 10 are arranged in an array (for example, a one-dimensional array, a two-dimensional array, etc.). As an example, the plurality of surface-emitting lasers 10 share a substrate 101, a first cladding layer 102, an active layer 103, a second cladding layer 104, and an insulating layer 105.

[0209] Each of the multiple surface-emitting lasers 10 has an electrode layout that is anode-independent and has a common cathode, and can be driven independently.

[0210] The surface-emitting laser array 220 provides a surface-emitting laser array in which surface-emitting lasers 10 capable of emitting only single-mode light are arranged in an array.

[0211] Furthermore, the surface-emitting laser array 220 can be configured as either a surface-emitting or back-emitting type by appropriately setting the relative reflectances of the first and second reflective structures RS1 and RS2.

[0212] <23. Surface-emitting laser according to Example 23 of one embodiment of the present technology> Hereinafter, a surface-emitting laser according to Example 23 of one embodiment of the present technology will be described with reference to the drawings. Figure 44 is a cross-sectional view of the surface-emitting laser 230 according to Example 23 of one embodiment of the present technology.

[0213] As shown in Figure 44, the surface-emitting laser 230 has a configuration that is generally the same as the surface-emitting laser 10 according to Embodiment 1, except that a stepped portion with an electrode mounting portion 102b as its bottom surface is provided in the first cladding layer 102, and a cathode electrode 111 is arranged on the electrode mounting portion 102b.

[0214] The surface-emitting laser 230 provides the same effects as the surface-emitting laser 10 according to Example 1, while also reducing series resistance and achieving power savings. Furthermore, a low-doped substrate, a semi-insulating substrate (for example, an SI (Semi-Insulating)-GaN substrate), or other high-resistance substrate can be used for the substrate 101.

[0215] Furthermore, the surface-emitting laser 230 can be configured as either a surface-emitting or back-emitting type by appropriately setting the relative reflectances of the first and second reflection structures RS1 and RS2.

[0216] <24. Surface-emitting laser according to Example 24 of one embodiment of the present technology> Hereinafter, a surface-emitting laser according to Example 24 of one embodiment of the present technology will be described with reference to the drawings. Figure 45 is a cross-sectional view of the surface-emitting laser 240 according to Example 24 of one embodiment of the present technology.

[0217] As shown in Figure 45, the surface-emitting laser 240 has a configuration that is generally the same as the surface-emitting laser 10 according to Embodiment 1, except that the first cladding layer 102 is not provided.

[0218] In the surface-emitting laser 240, the n-GaN substrate, which serves as the substrate 101, also plays the role of an n-type cladding layer.

[0219] The surface-emitting laser 240 provides the same effects as the surface-emitting laser 10 according to Example 1, while also simplifying the configuration and manufacturing process.

[0220] Furthermore, the surface-emitting laser 240 can be configured as either a surface-emitting or back-emitting type by appropriately setting the relative reflectances of the first and second reflection structures RS1 and RS2.

[0221] <25. Surface-emitting laser according to Example 25 of one embodiment of the present technology> Hereinafter, a surface-emitting laser according to Example 25 of one embodiment of the present technology will be described with reference to the drawings. Figure 46 is a cross-sectional view of a surface-emitting laser 250 according to Example 25 of one embodiment of the present technology.

[0222] As shown in Figure 46, the surface-emitting laser 250 has the same configuration as the surface-emitting laser 10 according to Example 1, except that the intermediate structure MS is a GaAs-based VCSEL containing a GaAs-based compound semiconductor (a compound semiconductor lattice-matched to GaAs).

[0223] In the surface-emitting laser 250, as an example, a first cladding layer 102, an active layer 103, a second cladding layer 104, a plane mirror as a second reflector 107, an insulating layer 105, and a transparent conductive film 106 are laminated on a substrate 101 in this order. A concave mirror as a first reflector 108 is provided on the back surface of the substrate 101. A circumferential (e.g., ring-shaped) anode electrode 109 is provided on the periphery of the transparent conductive film 106. In addition, an oxidation constriction layer and / or an ion implantation region may be provided instead of the insulating layer 105.

[0224] Here, the substrate 101 is made of n-GaAs, the first cladding layer 102 is made of n-AlGaAs, the active layer 103 is made of a GaAs-based compound semiconductor (e.g., GaAs, AlGaAs, InGaAs, InGaAsN, etc.), the second cladding layer 104 is made of p-AlGaAs, and the second reflector 107 is made of a p-type semiconductor multilayer reflector (e.g., p-AlGaAs / p-AlGaAs, p-GaAs / p-AlGaAs, p-GaAs / p-AlAs, p-AlGaAs / p-AlAs, etc.).

[0225] The active layer 103 may have any of the following structures: a quantum well structure, a multiple quantum well structure, a quantum nanowire structure, or a quantum dot structure. The emission wavelength of the active layer 103 is set to, for example, 400 nm to 1550 nm.

[0226] The active layer 103 is designed according to the oscillation wavelength λ and application. For example, to obtain laser characteristics in the 900 nm band at an oscillation wavelength λ, the active layer 103 can be designed using a combination of an InGaAs-based active layer and an AlGaAs-based guide / barrier layer.

[0227] The surface-emitting laser 250 provides a GaAs-based VCSEL that exhibits the same effects as the surface-emitting laser 10 according to Example 1.

[0228] Furthermore, the surface-emitting laser 250 can be configured as either a front-emitting or back-emitting type by appropriately setting the relative reflectances of the first and second reflective structures RS1 and RS2.

[0229] <26. Surface-emitting laser according to Example 26 of one embodiment of the present technology> Hereinafter, a surface-emitting laser according to Example 26 of one embodiment of the present technology will be described with reference to the drawings. Figure 47 is a cross-sectional view of the surface-emitting laser 260 according to Example 26 of one embodiment of the present technology.

[0230] As shown in Figure 47, the surface-emitting laser 260 has a configuration that is generally the same as the surface-emitting laser 250 according to Example 25 (see Figure 46), except that the first cladding layer 102 is not provided.

[0231] In the surface-emitting laser 260, the n-GaAs substrate 101 also plays the role of an n-type cladding layer.

[0232] The surface-emitting laser 260 provides the same effects as the surface-emitting laser 250 according to Example 25, while also simplifying the configuration and manufacturing process.

[0233] Furthermore, the surface-emitting laser 260 can be configured as either a surface-emitting or back-emitting type by appropriately setting the relative reflectances of the first and second reflective structures RS1 and RS2.

[0234] <27. Surface-emitting laser according to Example 27 of one embodiment of the present technology> Hereinafter, a surface-emitting laser according to Example 27 of one embodiment of the present technology will be described with reference to the drawings. Figure 48 is a cross-sectional view of the surface-emitting laser 270 according to Example 27 of one embodiment of the present technology.

[0235] As shown in Figure 48, the surface-emitting laser 270 has a configuration that is generally the same as the surface-emitting laser 250 according to Example 25 (see Figure 46), except that the first and second cladding layers 102 and 104 are not provided.

[0236] In the surface-emitting laser 270, the n-GaAs substrate 101 also functions as an n-type cladding layer, and the plane mirror second reflector 107 also functions as a p-type cladding layer.

[0237] The surface-emitting laser 270 provides the same effects as the surface-emitting laser 250 in Example 25, while also significantly simplifying the configuration and manufacturing process.

[0238] Furthermore, the surface-emitting laser 270 can be configured as either a surface-emitting or back-emitting type by appropriately setting the relative reflectances of the first and second reflective structures RS1 and RS2.

[0239] <28. Surface-emitting laser according to Example 28 of one embodiment of the present technology> Hereinafter, a surface-emitting laser according to Example 28 of one embodiment of the present technology will be described with reference to the drawings. Figure 49 is a cross-sectional view of the surface-emitting laser 280 according to Example 28 of one embodiment of the present technology.

[0240] The surface-emitting laser 280 has the same configuration as the surface-emitting laser 250 according to Example 25 (see Figure 46), except that it is limited to a back-side emission type, as shown in Figure 49.

[0241] In the surface-emitting laser 280, the anode electrode 109 is provided in a solid form across the entire surface of the transparent conductive film 106 and also functions as a metallic reflector. That is, in the surface-emitting laser 280, the second reflection structure RS2 has a hybrid mirror that includes a plane mirror as the second reflector 107 and the anode electrode 109 as a metallic reflector.

[0242] The surface-emitting laser 280 provides the same effects as the surface-emitting laser 250 according to Example 25, while also enabling lower resistance (e.g., reduced contact resistance) between the laser driver and the anode electrode 109 due to the increased area, and providing a back-side emission VCSEL with excellent single-mode light extraction efficiency.

[0243] <29. Surface-emitting laser according to Example 29 of one embodiment of the present technology> Hereinafter, a surface-emitting laser according to Example 29 of one embodiment of the present technology will be described with reference to the drawings. Figure 50 is a cross-sectional view of the surface-emitting laser 290 according to Example 29 of one embodiment of the present technology.

[0244] As shown in Figure 50, the surface-emitting laser 290 has a configuration that is generally the same as the surface-emitting laser 250 according to Example 25 (see Figure 46), except that it does not have a transparent conductive film 106 and has an oxidized constriction layer 115 instead of an insulating layer 105.

[0245] In the surface-emitting laser 290, an oxide constriction layer 115 and a plane mirror serving as the second reflector 107 are arranged in that order on the second cladding layer 104. A circumferential (for example, ring-shaped) anode electrode 109 is provided on the periphery of the plane mirror serving as the second reflector 107.

[0246] The oxidized constriction layer 115 has a non-oxidized region 115a and an oxidized region 115b surrounding the non-oxidized region 115a. The oxidized constriction layer 115 has a current and light constriction function because the oxidized region 115b has higher resistance and a lower refractive index than the non-oxidized region 115a. For example, the non-oxidized region 115a is made of a GaAs-based compound semiconductor (e.g., AlAs), and the oxidized region 115b is made of an oxide (e.g., Al2O3). The constriction diameter of the oxidized constriction layer 115 (diameter of the non-oxidized region 115a) is, for example, 3 to 10 μm.

[0247] The surface-emitting laser 290 provides the same effects as the surface-emitting laser 250 according to Example 25, and also offers a surface-emitting laser that can generate a resonator (except for the first reflection structure RS1) by epitaxial growth.

[0248] Furthermore, the surface-emitting laser 290 can be configured as either a surface-emitting or back-emitting type by appropriately setting the relative reflectances of the first and second reflective structures RS1 and RS2.

[0249] <30. Surface-emitting laser according to Example 30 of one embodiment of the present technology> Hereinafter, a surface-emitting laser according to Example 30 of one embodiment of the present technology will be described with reference to the drawings. Figure 51 is a cross-sectional view of a surface-emitting laser 300 according to Example 30 of one embodiment of the present technology.

[0250] As shown in Figure 51, the surface-emitting laser 300 has a configuration that is generally the same as the surface-emitting laser 290 according to Example 29 (see Figure 50), except that an ion implantation region IIA is provided.

[0251] In the surface-emitting laser 300, a planar circumferential ion implantation region IIA is provided in the resonator (for example, the second reflector 107, the oxidation region 115b, the second cladding layer 104, the active layer 103, and the first cladding layer 102) so as to surround the non-oxidizing region 115a of the oxidation constriction layer 115.

[0252] The surface-emitting laser 300 provides the same effects as the surface-emitting laser 290 in Example 29, and because an ion implantation region IIA is provided in addition to the oxidative constriction layer 115, the current injection efficiency into the active layer 103 can be further improved.

[0253] Furthermore, the surface-emitting laser 300 can be configured as either a surface-emitting or back-emitting type by appropriately setting the relative reflectances of the first and second reflective structures RS1 and RS2.

[0254] <31. Surface-emitting laser according to Example 31 of one embodiment of the present technology> Hereinafter, a surface-emitting laser according to Example 31 of one embodiment of the present technology will be described with reference to the drawings. Figure 52 is a cross-sectional view of the surface-emitting laser 310 according to Example 31 of one embodiment of the present technology.

[0255] As shown in Figure 52, the surface-emitting laser 310 has a configuration that is generally the same as the surface-emitting laser 10 according to Example 1, except that the intermediate structure MS is an InP-based VCSEL containing an InP-based compound semiconductor (a compound semiconductor lattice-matched to InP).

[0256] In the surface-emitting laser 310, a transparent conductive film 106 is not provided, and a BTJ (buried tunnel junction) is provided instead of an insulating layer 105.

[0257] In the surface-emitting laser 310, a first cladding layer 102, an active layer 103, a second cladding layer 104, a BTJ, and a plane mirror serving as the second reflector 107 are stacked on the substrate 101 in this order. A circumferential (e.g., ring-shaped) anode electrode 109 is provided on the periphery of the plane mirror serving as the second reflector 107. A concave mirror (e.g., a dielectric multilayer reflector) serving as the first reflector 108 is provided on the first convex surface 101a on the back surface of the substrate 101.

[0258] (Substrate) The substrate 101 is made of a conductive material, for example, n-InP. For example, Si can be used as the n-type dopant of the n-InP.

[0259] (First reflecting mirror) The concave mirror used as the first reflecting mirror 108 is, for example, a dielectric multilayer reflecting mirror.

[0260] (First cladding layer) The first cladding layer 102 is, for example, made of an n-type compound semiconductor, such as n-InP. For example, Si can be used as the n-type dopant of the n-InP.

[0261] (Active layer) The active layer 103 is made of an InP-based compound semiconductor, for example. More specifically, the active layer 103 has a multiple quantum well structure (MQW structure), for example. Here, the active layer 103 is made of, for example, an AlGaInAs / AlGaInAs multiple quantum well layer. The composition and film thickness of the AlGaInAs / AlGaInAs multiple quantum well layer are designed so that the emission wavelength is, for example, 1450 nm (eye-safe band), but it is preferable to introduce opposing strains into the well layer and the barrier layer. In this case, for example, the magnitude of the strain can be about 0.5%, and the number of wells can be 6. The active layer 103 has an emission region in the region corresponding to the tunnel junction layer 116, which will be described later.

[0262] (Second cladding layer) The second cladding layer 104 is, for example, made of a p-type compound semiconductor, such as p-InP. For example, Mg can be used as the p-type dopant of the p-InP.

[0263] (BTJ) The BTJ includes a tunnel junction layer 116 and a burial layer 117. As described above, the BTJ is located on the opposite side (upper side) of the active layer 103 from the substrate 101 side. That is, the BTJ is located upstream of the active layer 103 in the current path from the anode electrode 109 to the cathode electrode 111.

[0264] The embedded layer 117 is made of, for example, an n-InP layer. For example, Si can be used as the dopant for the n-InP layer.

[0265] The tunnel junction layer 116 is provided in a mesa-like manner on the second cladding layer 104. Therefore, in the following, the tunnel junction layer 116 will also be referred to as the "TJ mesa". The region of the embedding layer 117 surrounding the TJ mesa has a higher resistance than the TJ mesa, thus becoming a current-constricted region. The region of the embedding layer 117 surrounding the TJ mesa has a lower refractive index than the TJ mesa, thus becoming an optical-constricted region. The diameter of the TJ mesa is, for example, several micrometers to several tens of micrometers.

[0266] The tunnel junction layer 116 includes a p-type semiconductor region 116a and an n-type semiconductor region 116b stacked on top of each other. Here, the p-type semiconductor region 116a is located on the active layer 103 side (lower side) of the n-type semiconductor region 116b. The p-type semiconductor region 116a is made of p-type AlInAs (p-AlInAs) doped with a high concentration of carbon (C), for example. The n-type semiconductor region 116b is made of n-type InP (n-InP) doped with a high concentration of Si, Te, etc., for example. Note that one of the p-type semiconductor region 116a and the n-type semiconductor region 116b may be made of AlInAs and the other of InP, or both may be made of AlInAs or InP.

[0267] (Second Reflector) The plane mirror as the second reflector 107 is, for example, a semiconductor multilayer reflector, such as an InP-based semiconductor multilayer reflector. Specifically, the plane mirror as the second reflector 107 is, for example, made of p-InP / p-AlGaInAs or p-AlInAs / p-AlGaInAs.

[0268] The surface-emitting laser 310 provides an InP-based VCSEL that exhibits the same effects as the surface-emitting laser 10 according to Example 1.

[0269] Furthermore, the surface-emitting laser 310 can be configured as either a surface-emitting or back-emitting type by appropriately setting the relative reflectances of the first and second reflective structures RS1 and RS2.

[0270] <32. Surface-emitting laser according to Example 32 of one embodiment of the present technology> Hereinafter, a surface-emitting laser according to Example 32 of one embodiment of the present technology will be described with reference to the drawings. Figure 53 is a cross-sectional view of a surface-emitting laser 320 according to Example 32 of one embodiment of the present technology.

[0271] The surface-emitting laser 320 has a configuration that is generally the same as the surface-emitting laser 310 according to Example 31 (see Figure 52), except that it has an oxidative constriction structure instead of a BTJ, as shown in Figure 53.

[0272] In the surface-emitting laser 320, as an example, a tunnel junction layer 116 is provided on the second cladding layer 104, and an n-type semiconductor layer 118 (for example, an n-InP layer) is provided between the tunnel junction layer 116 and the second reflector 107.

[0273] Here, the p-type semiconductor region 116a of the tunnel junction layer 116 has an oxidative constriction structure in which the non-oxidized region 116a1 is surrounded by the oxidized region 116a2. Alternatively, an n-type semiconductor region 116b may have an oxidative constriction structure in place of or in addition to the p-type semiconductor region 116a.

[0274] The surface-emitting laser 320 provides an InP-based VCSEL that exhibits the same effects as the surface-emitting laser 10 according to Example 1.

[0275] Furthermore, the surface-emitting laser 320 can be configured as either a front-emitting or back-emitting type by appropriately setting the relative reflectances of the first and second reflective structures RS1 and RS2.

[0276] <33. Surface-emitting laser according to Example 33 of one embodiment of the present technology> Hereinafter, a surface-emitting laser according to Example 33 of one embodiment of the present technology will be described with reference to the drawings. Figure 54 is a cross-sectional view of the surface-emitting laser 330 according to Example 33 of one embodiment of the present technology.

[0277] The surface-emitting laser 330 has a configuration that is generally the same as the surface-emitting laser 70 according to Embodiment 7 (see Figure 23), except that, as shown in Figure 54, a depression DP is provided in the central part 101a1 of the first convex surface 101a of the substrate 101.

[0278] In the surface-emitting laser 330, the surface irregularities DP are formed by a plurality of protrusions P provided on the central portion 101a1 of the first convex surface 101a and recesses D between the protrusions P. This provides an anchoring effect and suppresses the peeling of the concave mirror.

[0279] In the surface-emitting laser 330, single-mode oscillation can be suppressed in the central part of the resonator due to optical loss caused by the uneven DP provided on the central part 101a1 of the first convex surface 101a, and multi-mode oscillation can be made possible because the peripheral part 101a2 of the first convex surface 101a is, for example, a smooth surface and has no or almost no optical loss, making it possible to extract only multi-mode light.

[0280] The surface-emitting laser 330 provides a surface-emitting laser that can obtain the gain necessary for oscillation regardless of the resonator length and can control transverse modes (specifically, it can suppress single-mode oscillation and can oscillate in multiple modes).

[0281] Furthermore, the surface-emitting laser 330 can be configured as either a surface-emitting or back-emitting type by appropriately setting the relative reflectances of the first and second reflective structures RS1 and RS2.

[0282] <34. Surface-emitting laser according to Example 34 of one embodiment of the present technology> Hereinafter, a surface-emitting laser according to Example 34 of one embodiment of the present technology will be described with reference to the drawings. Figure 55 is a cross-sectional view of a surface-emitting laser 340 according to Example 34 of one embodiment of the present technology.

[0283] As shown in Figure 55, the surface-emitting laser 340 has a configuration that is generally the same as the surface-emitting laser 70 according to Embodiment 7 (see Figure 23), except that the central part 101a1 of the first convex surface 101a of the substrate 101 has irregularities DP.

[0284] In the surface-emitting laser 340, the surface surface DP is formed by a plurality of recesses D provided in the central portion 101a1 of the first convex surface 101a and the convex portions P of the recesses D. This provides an anchoring effect and suppresses the peeling of the concave mirror.

[0285] In the surface-emitting laser 340, single-mode oscillation can be suppressed in the central part of the resonator due to optical loss caused by the uneven DP provided on the central part 101a1 of the first convex surface 101a, and multi-mode oscillation can be made possible because the peripheral part 101a2 of the first convex surface 101a is, for example, a smooth surface and has no or almost no optical loss, making it possible to extract only multi-mode light.

[0286] The surface-emitting laser 340 provides a surface-emitting laser that can obtain the gain necessary for oscillation regardless of the resonator length and can control transverse modes (specifically, it can suppress single-mode oscillation and can oscillate in multiple modes).

[0287] Furthermore, the surface-emitting laser 340 can be configured as either a front-emitting or back-emitting type by appropriately setting the relative reflectances of the first and second reflective structures RS1 and RS2.

[0288] <35. Surface-emitting laser according to Example 35 of one embodiment of the present technology> Hereinafter, a surface-emitting laser according to Example 35 of one embodiment of the present technology will be described with reference to the drawings. Figure 56 is a cross-sectional view of a surface-emitting laser 350 according to Example 35 of one embodiment of the present technology.

[0289] In the surface-emitting laser 350, as shown in Figure 56, the concave mirror, which serves as the first reflector 108, has a configuration that is generally the same as that of the surface-emitting laser 190 according to Example 19 (see Figure 40), except that the number of pairs of high-refractive-index layers and low-refractive-index layers in the central part 108A (central part of the concave mirror) and the peripheral part 108B (peripheral part of the concave mirror) are reversed.

[0290] In the surface-emitting laser 350, the number of pairs of lasers around the concave mirror is greater than the number of pairs of lasers around the center of the concave mirror. More specifically, the number of pairs of lasers around the center of the concave mirror is set to a number that prevents single-mode oscillation, while the number of pairs around the concave mirror is set to a number that enables multi-mode oscillation.

[0291] Although the surface-emitting laser 350 cannot achieve an anchoring effect, it can obtain effects that are generally similar to those of the surface-emitting laser 330 (see Figure 54) according to Example 33.

[0292] Furthermore, the surface-emitting laser 350 can be configured as either a front-emitting or back-emitting type by appropriately setting the relative reflectances of the first and second reflective structures RS1 and RS2.

[0293] <36. Surface-emitting laser according to Example 36 of one embodiment of the present technology> Hereinafter, a surface-emitting laser according to Example 36 of one embodiment of the present technology will be described with reference to the drawings. Figure 57 is a cross-sectional view of the surface-emitting laser 360 according to Example 36 of one embodiment of the present technology.

[0294] As shown in Figure 57, the surface-emitting laser 360 has a configuration that is generally the same as the surface-emitting laser 200 according to Example 20 (see Figure 41), except that the first reflecting mirror 108, which is a concave mirror (for example, a dielectric multilayer reflecting mirror), is provided only in the peripheral portion 101a2 of the first convex surface 101a.

[0295] In the surface-emitting laser 360, the first reflective structure RS1 has a reflectivity in the central part that does not include the concave mirror that is unable to emit single-mode light, and a reflectivity in the peripheral part that includes the concave mirror that is capable of emitting multi-mode light.

[0296] Although the surface-emitting laser 360 cannot achieve an anchoring effect, it can obtain effects that are generally similar to those of the surface-emitting laser 330 (see Figure 54) in Example 33.

[0297] Furthermore, the surface-emitting laser 360 can be configured as either a surface-emitting or back-emitting type by appropriately setting the relative reflectances of the first and second reflective structures RS1 and RS2.

[0298] <37. Surface-emitting laser according to Example 37 of one embodiment of the present technology> Hereinafter, a surface-emitting laser according to Example 37 of one embodiment of the present technology will be described with reference to the drawings. Figure 58 is a cross-sectional view of the surface-emitting laser 370 according to Example 37 of one embodiment of the present technology.

[0299] As shown in Figure 58, the surface-emitting laser 370 has a configuration that is generally the same as the surface-emitting laser 13 according to Example 13 (see Figure 32), except that a thin film 113 is provided on the central part 101a1 of the first convex surface 101a.

[0300] The thin film 113 is an oxide film (e.g., GaO) or a chloride film (e.g., GaCl). The thin film 113 is projected from the central portion 101a1 of the first convex surface 101a. This provides an anchoring effect, which suppresses peeling of the concave mirror.

[0301] In the surface-emitting laser 370, the first reflective structure RS1 has a significantly reduced reflectivity in the central part (low reflectivity region LRA) where the thin film 113 is provided, thus suppressing single-mode oscillation. On the other hand, the desired reflectivity can be obtained in the peripheral part (high reflectivity region HRA) where the thin film 113 is not provided, allowing for multi-mode oscillation.

[0302] The surface-emitting laser 370 produces effects that are generally similar to those of the surface-emitting laser 330 according to Example 33 (see Figure 54).

[0303] Furthermore, the surface-emitting laser 370 can be configured as either a front-emitting or back-emitting type by appropriately setting the relative reflectances of the first and second reflective structures RS1 and RS2.

[0304] <38. Surface-emitting laser according to Example 38 of one embodiment of the present technology> Hereinafter, a surface-emitting laser according to Example 38 of one embodiment of the present technology will be described with reference to the drawings. Figure 59 is a cross-sectional view of the surface-emitting laser 380 according to Example 38 of one embodiment of the present technology.

[0305] As shown in Figure 59, the surface-emitting laser 380 has a configuration that is generally the same as the surface-emitting laser 60 according to Embodiment 6 (see Figure 22), except that the first reflective structure RS1 has a curved surface 101c on the back surface of the substrate 101, with a central portion 101c1 being concave and a peripheral portion 101c2 being convex.

[0306] In the surface-emitting laser 380, the same roughness difference as in the surface-emitting laser 10 is not provided between the central part 101c1 and the peripheral part 101c2 of the curved surface 101c.

[0307] In the surface-emitting laser 380, the first reflection structure RS1 suppresses single-mode oscillation due to optical loss caused by diffusion in the concave central portion 101c1 of the curved surface 101c, while the peripheral portion 101c2 of the curved surface 101c2 can generate multi-mode oscillation due to the focusing effect (lateral light confinement effect) on the convex light-emitting region.

[0308] The surface-emitting laser 380 produces effects that are generally similar to those of the surface-emitting laser 330 according to Example 33 (see Figure 54).

[0309] <39. Surface-emitting laser according to Example 39 of one embodiment of the present technology> Hereinafter, a surface-emitting laser according to Example 39 of one embodiment of the present technology will be described with reference to the drawings. Figure 60 is a cross-sectional view of the surface-emitting laser 390 according to Example 39 of one embodiment of the present technology.

[0310] As shown in Figure 60, the surface-emitting laser 390 has a configuration that is generally the same as the surface-emitting laser 10 according to Example 1, except that the first reflection structure RS1 has a difference in roughness between the central part 101a1 and the peripheral part 101a2 of the first convex surface 101a, and a difference in the number of pairs between the central part and the peripheral part of the concave mirror.

[0311] In the surface-emitting laser 390, the roughness of the area around the concave mirror is higher than the roughness of the area in the center of the concave mirror, and the number of pairs in the center of the concave mirror is greater than the number of pairs in the area around the concave mirror.

[0312] The surface-emitting laser 390 provides generally the same effects as the surface-emitting laser 10 according to Example 1, while also improving the single-mode extraction efficiency.

[0313] Furthermore, the surface-emitting laser 390 can be configured as either a surface-emitting or back-emitting type by appropriately setting the relative reflectances of the first and second reflective structures RS1 and RS2.

[0314] <40. Surface-emitting laser according to Example 40 of one embodiment of the present technology> Hereinafter, a surface-emitting laser according to Example 40 of one embodiment of the present technology will be described with reference to the drawings. Figure 61 is a cross-sectional view of a surface-emitting laser 400 according to Example 40 of one embodiment of the present technology.

[0315] As shown in Figure 61, the surface-emitting laser 400 has a configuration that is generally the same as the surface-emitting laser 50 according to Embodiment 5 (see Figure 15), except that the type and arrangement of the plane mirrors used as the second reflector 107 are different.

[0316] In the surface-emitting laser 400, the plane mirror serving as the second reflector 107 is a dielectric multilayer reflector, the layer configuration on the first cladding layer 102 is the same as that of the surface-emitting laser 10 according to Example 1, and the layer configuration below the first cladding layer 102 is the same as that of the surface-emitting laser 50 according to Example 5.

[0317] The surface-emitting laser 400 provides the same effects as the surface-emitting laser 50 according to Example 5.

[0318] Furthermore, the surface-emitting laser 400 can be configured as either a front-emitting or back-emitting type by appropriately setting the relative reflectances of the first and second reflective structures RS1 and RS2.

[0319] <41. Surface-emitting laser according to Example 41 of one embodiment of the present technology> Hereinafter, a surface-emitting laser according to Example 41 of one embodiment of the present technology will be described with reference to the drawings. Figure 62 is a cross-sectional view of a surface-emitting laser 410 according to Example 41 of one embodiment of the present technology.

[0320] As shown in Figure 62, the surface-emitting laser 410 has a configuration that is generally the same as the surface-emitting laser 180 according to Embodiment 18 (see Figure 39), except that the metal reflector 114 is provided across the back surface of the concave mirror, which serves as the first reflector 108, and the back surface of the substrate 101.

[0321] In the surface-emitting laser 410, the substrate 101 does not have an electrode mounting section 101b, nor does it have a cathode electrode 111.

[0322] In the surface-emitting laser 410, the metal reflector 114 also functions as a cathode electrode. The lower surface of the metal reflector 114 has a third convex surface 114a that is convex on the opposite side (downward) from the second reflective structure RS2 side.

[0323] The surface-emitting laser 410 provides the same effects as the surface-emitting laser 180 in Example 18, eliminates the need for the cathode electrode 111, and suppresses peeling of the metal reflector 114 due to the anchoring effect of the high-roughness region on the metal reflector 114.

[0324] <42. Surface-emitting laser according to Example 42 of one embodiment of the present technology> Hereinafter, a surface-emitting laser according to Example 42 of one embodiment of the present technology will be described with reference to the drawings. Figure 63 is a cross-sectional view of a surface-emitting laser 420 according to Example 42 of one embodiment of the present technology.

[0325] As shown in Figure 63, the surface-emitting laser 420 has a configuration that is generally the same as the surface-emitting laser 210 according to Example 21 (see Figure 42), except that the second reflecting mirror 107 is a concave mirror.

[0326] In the surface-emitting laser 420, for example, the upper surface of the transparent conductive film 106 includes a convex surface that is convex on the side opposite to (upwards) the first reflective structure RS1, and a concave mirror as the second reflecting mirror 107 is provided on this convex surface.

[0327] The surface-emitting laser 420 provides the same effects as the surface-emitting laser 210 according to Example 21, and also provides a lateral light confinement effect by the concave mirror of the first reflective structure RS1 and a lateral light confinement effect by the concave mirror of the second reflective structure RS2, thus providing a more efficient surface-emitting laser.

[0328] Furthermore, the surface-emitting laser 420 can be configured as either a front-emitting or back-emitting type by appropriately setting the relative reflectances of the first and second reflective structures RS1 and RS2.

[0329] <43. Surface-emitting laser according to Example 43 of one embodiment of the present technology> Hereinafter, a surface-emitting laser according to Example 43 of one embodiment of the present technology will be described with reference to the drawings. Figure 64 is a cross-sectional view of a surface-emitting laser 430 according to Example 43 of one embodiment of the present technology.

[0330] As shown in Figure 64, the surface-emitting laser 430 has the same configuration as the surface-emitting laser 60 according to Embodiment 6 (see Figure 22), except that an anti-reflective film 112 is not provided on the back surface of the substrate 101.

[0331] Although the surface-emitting laser 430 does not provide the anti-reflective function of the anti-reflective coating 112, it allows for a simplified configuration.

[0332] <44. Modifications of this technology> This technology is not limited to the above embodiments and can be modified in various ways.

[0333] In the surface-emitting lasers according to each of the above embodiments, the entire back surface of the substrate 101 may be convex.

[0334] The conductivity types (p-type and n-type) of the constituent layers of the surface-emitting laser according to each of the above embodiments may be interchanged.

[0335] Some of the configurations of the surface-emitting lasers according to each of the above embodiments may be combined within a range that is not contradictory to one another.

[0336] In each of the above embodiments, the material, thickness, width, length, shape, size, arrangement, etc., of each component constituting the surface-emitting laser can be appropriately changed within the range in which it functions as a surface-emitting laser.

[0337] <45. Examples of Application to Electronic Devices> The technology relating to this disclosure (this technology) can be applied to various products (electronic devices). For example, the technology relating to this disclosure may be implemented as a device mounted on any type of mobile vehicle such as automobiles, electric vehicles, hybrid electric vehicles, motorcycles, bicycles, personal mobility devices, airplanes, drones, ships, and robots (e.g., a distance measuring device, a shape recognition device, etc.), a low-power consumption device (smartphone, smartwatch, tablet, mouse, laptop, etc.), or a communication device.

[0338] The surface-emitting laser related to this technology can be applied, for example, as a light source or the display itself in devices that form or display images using laser light (e.g., laser printers, laser copiers, projectors, head-mounted displays, head-up displays, etc.).

[0339] <46. Examples of applying surface-emitting lasers to distance measuring devices> The following describes examples of applying surface-emitting lasers according to each of the above embodiments.

[0340] Figure 65 shows an example of the schematic configuration of a distance measuring device 1000 (distance measuring device) equipped with a surface-emitting laser 10, as an example of electronic equipment related to this technology. The distance measuring device 1000 measures the distance to a subject S using the TOF (Time Of Flight) method. The distance measuring device 1000 is equipped with a surface-emitting laser 10 as a light source. The distance measuring device 1000 includes, for example, a surface-emitting laser 10, a light receiving device 125, lenses 119 and 131, a signal processing unit 141, a control unit 151, a display unit 161, and a storage unit 171.

[0341] The surface-emitting laser 10 is driven by a laser driver (driver). The laser driver has an anode terminal and a cathode terminal that are connected to the anode electrode and cathode electrode of the surface-emitting laser 10 via wiring or conductive bumps, respectively. The laser driver is composed of circuit elements such as capacitors and transistors.

[0342] The light receiving device 125 detects the light reflected from the subject S. Lens 119 is a collimating lens that aligns the light emitted from the surface-emitting laser 10. Lens 131 is a focusing lens that collects the light reflected from the subject S and guides it to the light receiving device 125.

[0343] The signal processing unit 141 is a circuit for generating a signal corresponding to the difference between the signal input from the light receiving device 125 and the reference signal input from the control unit 151. The control unit 151 is configured to include, for example, a Time to Digital Converter (TDC). The reference signal may be a signal input from the control unit 151, or it may be an output signal from a detection unit that directly detects the output of the surface-emitting laser 10. The control unit 151 is a processor that controls, for example, the surface-emitting laser 10, the light receiving device 125, the signal processing unit 141, the display unit 161, and the storage unit 171. The control unit 151 is a circuit for measuring the distance to the subject S based on the signal generated by the signal processing unit 141. The control unit 151 generates a video signal for displaying information about the distance to the subject S and outputs it to the display unit 161. The display unit 161 displays information about the distance to the subject S based on the video signal input from the control unit 151. The control unit 151 stores the information about the distance to the subject S in the storage unit 171.

[0344] In this application example, instead of the surface-emitting laser 10, any of the surface-emitting lasers 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 160, 165, 170, 175, 180, 190, 200, 210, 220, 230, 240, 250, 260, 270, 280, 290, 300, 310, 320, 330, 340, 350, 360, 370, 380, 390, 400, 410, or 420 can be applied to the distance measuring device 1000. Furthermore, when applying a surface-emitting laser array having multiple surface-emitting lasers to the distance measuring device 1000, a laser driver that individually drives the multiple surface-emitting lasers can also be used. <47. Example of a distance measuring device mounted on a mobile body>

[0345] Figure 66 is a block diagram showing a schematic configuration example of a vehicle control system, which is an example of a mobile control system to which the technology described herein may be applied.

[0346] The vehicle control system 12000 comprises a plurality of electronic control units connected via a communication network 12001. In the example shown in Figure 66, the vehicle control system 12000 includes a drive system control unit 12010, a body system control unit 12020, an external information detection unit 12030, an internal information detection unit 12040, and an integrated control unit 12050. The functional configuration of the integrated control unit 12050 is shown in the figure, which includes a microcomputer 12051, an audio / image output unit 12052, and an in-vehicle network interface 12053.

[0347] The drivetrain control unit 12010 controls the operation of devices related to the vehicle's drivetrain according to various programs. For example, the drivetrain control unit 12010 functions as a control device for a drivetrain generating device that generates driving force for the vehicle, such as an internal combustion engine or a drive motor; a drivetrain transmission mechanism that transmits driving force to the wheels; a steering mechanism that adjusts the steering angle of the vehicle; and a braking device that generates braking force for the vehicle.

[0348] The body system control unit 12020 controls the operation of various devices mounted on the vehicle body according to various programs. For example, the body system control unit 12020 functions as a control device for a keyless entry system, a smart key system, a power window system, or various lamps such as headlights, reverse lights, brake lights, turn signals, or fog lights. In this case, the body system control unit 12020 may receive radio waves transmitted from a portable device that replaces a key or signals from various switches. The body system control unit 12020 receives these radio waves or signals and controls the vehicle's door lock system, power window system, lamps, etc.

[0349] The external information detection unit 12030 detects information from outside the vehicle equipped with the vehicle control system 12000. For example, a distance measuring device 12031 is connected to the external information detection unit 12030. The distance measuring device 12031 includes the distance measuring device 1000 described above. The external information detection unit 12030 causes the distance measuring device 12031 to measure the distance to an object outside the vehicle (subject S) and acquires the distance data obtained thereby. Based on the acquired distance data, the external information detection unit 12030 may perform object detection processing for people, cars, obstacles, signs, etc.

[0350] The in-vehicle information detection unit 12040 detects information inside the vehicle. The in-vehicle information detection unit 12040 is connected to, for example, a driver status detection unit 12041 that detects the driver's state. The driver status detection unit 12041 includes, for example, a camera that captures images of the driver, and the in-vehicle information detection unit 12040 may calculate the driver's level of fatigue or concentration, or determine whether the driver is drowsy, based on the detection information input from the driver status detection unit 12041.

[0351] The microcomputer 12051 can calculate control target values ​​for the drive force generator, steering mechanism, or braking device based on information inside and outside the vehicle acquired by the external information detection unit 12030 or the internal information detection unit 12040, and output control commands to the drive system control unit 12010. For example, the microcomputer 12051 can perform cooperative control aimed at realizing ADAS (Advanced Driver Assistance System) functions, including vehicle collision avoidance or impact mitigation, following driving based on distance between vehicles, maintaining vehicle speed, vehicle collision warning, or vehicle lane departure warning.

[0352] Furthermore, the microcomputer 12051 can perform cooperative control for purposes such as autonomous driving, where the vehicle drives autonomously without driver intervention, by controlling the drive force generating device, steering mechanism, or braking device, etc., based on information about the vehicle's surroundings acquired by the external information detection unit 12030 or the internal information detection unit 12040.

[0353] Furthermore, the microcomputer 12051 can output control commands to the body system control unit 12020 based on external information acquired by the external information detection unit 12030. For example, the microcomputer 12051 can control the headlights according to the position of a preceding or oncoming vehicle detected by the external information detection unit 12030, and perform coordinated control aimed at reducing glare, such as switching from high beams to low beams.

[0354] The audio-image output unit 12052 transmits at least one of audio and image output signals to an output device capable of visually or audibly notifying information to the vehicle's occupants or to those outside the vehicle. In the example shown in Figure 66, the output devices include an audio speaker 12061, a display unit 12062, and an instrument panel 12063. The display unit 12062 may include, for example, at least one of an onboard display and a head-up display.

[0355] Figure 67 shows an example of the installation location of the distance measuring device 12031.

[0356] In Figure 67, the vehicle 12100 has distance measuring devices 12101, 12102, 12103, 12104, and 12105 as a distance measuring device 12031.

[0357] Distance measuring devices 12101, 12102, 12103, 12104, and 12105 are installed, for example, on the front nose, side mirrors, rear bumper, back door, and the upper part of the windshield inside the vehicle 12100. Distance measuring device 12101 installed on the front nose and distance measuring device 12105 installed on the upper part of the windshield inside the vehicle mainly acquire data in front of the vehicle 12100. Distance measuring devices 12102 and 12103 installed on the side mirrors mainly acquire data to the sides of the vehicle 12100. Distance measuring device 12104 installed on the rear bumper or back door mainly acquires data behind the vehicle 12100. The forward data acquired by distance measuring devices 12101 and 12105 is mainly used for detecting preceding vehicles, pedestrians, obstacles, traffic lights, traffic signs, etc.

[0358] Figure 67 shows an example of the detection ranges of distance measuring devices 12101 to 12104. Detection range 12111 indicates the detection range of distance measuring device 12101 installed on the front nose, detection ranges 12112 and 12113 indicate the detection ranges of distance measuring devices 12102 and 12103 installed on the side mirrors, respectively, and detection range 12114 indicates the detection range of distance measuring device 12104 installed on the rear bumper or back door.

[0359] For example, the microcomputer 12051, based on distance data obtained from distance measuring devices 12101 to 12104, can determine the distance to each object within the detection range 12111 to 12114 and the temporal change of this distance (relative speed to the vehicle 12100). In particular, it can extract the nearest object on the vehicle 12100's path that is traveling in approximately the same direction as the vehicle 12100 at a predetermined speed (e.g., 0 km / h or more) as the preceding vehicle. Furthermore, the microcomputer 12051 can set a predetermined distance to be maintained before the preceding vehicle and perform automatic braking control (including follow-and-stop control) and automatic acceleration control (including follow-and-start control), etc. In this way, cooperative control aimed at autonomous driving, where the vehicle drives autonomously without driver intervention, can be performed.

[0360] For example, the microcomputer 12051 can use distance data obtained from distance measuring devices 12101 to 12104 to classify and extract three-dimensional object data related to three-dimensional objects, such as motorcycles, passenger cars, large vehicles, pedestrians, utility poles, and other three-dimensional objects, and use this data for automatic obstacle avoidance. For example, the microcomputer 12051 identifies obstacles around the vehicle 12100 into obstacles that are visible to the driver of the vehicle 12100 and obstacles that are difficult to see. The microcomputer 12051 then determines the collision risk, which indicates the degree of risk of collision with each obstacle. If the collision risk is above a set value and there is a possibility of collision, the microcomputer 12051 can provide driving assistance to avoid a collision by outputting a warning to the driver via the audio speaker 12061 or display unit 12062, or by performing forced deceleration or evasive steering via the drive system control unit 12010.

[0361] The above describes an example of a mobile control system to which the technology described herein may be applied. The technology described herein may be applied to the distance measuring device 12031 of the configuration described above.

[0362] Furthermore, this technology can also take the following configurations: (1) A surface-emitting laser comprising: a first reflective structure; a second reflective structure; and an intermediate structure including an active layer sandwiched between the first reflective structure and the second reflective structure, wherein the first reflective structure has at least one convex surface that is convex on the side opposite to the second reflective structure, and has a reflectance distribution and / or reflection direction distribution in the in-plane direction. (2) The surface-emitting laser according to (1), wherein the first reflective structure has a first reflectance, which is the reflectance of the central part, and a second reflectance, which is the reflectance of the peripheral part, which is different. (3) The surface-emitting laser according to (2), wherein the active layer has an emission region, and the central part overlaps with the emission region in a plan view. (4) The surface-emitting laser according to (2) or (3), wherein the second reflectance is lower than the first reflectance. (5) The surface-emitting laser according to any one of (1) to (4), wherein the convex surface has a first roughness, which is the roughness of the central part, and a second roughness, which is the roughness of the peripheral part, which is different. (6) The surface-emitting laser according to (5), wherein the second roughness is higher than the first roughness. (7) The surface-emitting laser according to any one of (1) to (6), wherein the convex surface has irregularities in the central part or the peripheral part. (8) The surface-emitting laser according to (7), wherein the convex surface has the irregularities in the peripheral part. (9) The surface-emitting laser according to any one of (1) to (8), wherein the convex surface has an oxide film or a chloride film in the central part or the peripheral part. (10) The surface-emitting laser according to (9), wherein the convex surface has the oxide film or the chloride film in the peripheral part. (11) The surface-emitting laser according to any one of (1) to (10), wherein the convex surface has a radius of curvature distribution in the in-plane direction. (12) The surface-emitting laser according to (11), wherein the radius of curvature in the central part and the radius of curvature in the peripheral part are different. (13) The surface-emitting laser according to any one of (1) to (12), wherein the first reflective structure comprises a first convex surface as the convex surface and a second convex surface as the convex surface, the second convex surface located on the opposite side of the first convex surface from the second reflective structure side. (14) The surface-emitting laser according to (13), wherein the first reflective structure includes a concave mirror having a concave surface along the first convex surface on the first convex surface side and the second convex surface on the opposite side from the first convex surface side.(15) The surface-emitting laser according to (14), wherein the intermediate structure includes a portion of a substrate disposed on the first reflective structure side of the active layer, and the first convex surface is at least a portion of the surface of the substrate on the concave mirror side. (16) The surface-emitting laser according to any one of (1) to (15), wherein the first reflective structure includes a plane mirror and a substrate disposed on the opposite side of the plane mirror from the second reflective structure side, the substrate having the convex surface on the opposite side from the second reflective structure side. (17) The surface-emitting laser according to (16), wherein an anti-reflective film is provided on the convex surface. (18) When the resonator length is L, the radius of curvature of the convex surface is R, the oscillation wavelength is λ, and the average refractive index of the region between the convex surface and the second reflective structure is n, the diameter of the central part is 3[(λ / πn)[LR]. 2 (RL)] 1 / 2 ] 1 / 2 (1) to (17) a surface-emitting laser according to any one of (1) to (18). (19) A surface-emitting laser according to any one of (1) to (18), wherein at least one of the first and second reflective structures includes a dielectric multilayer mirror. (20) A surface-emitting laser according to any one of (1) to (19), wherein at least one of the first and second reflective structures includes a semiconductor multilayer mirror. (21) A surface-emitting laser according to any one of (1) to (20), wherein the intermediate structure includes a III-V compound semiconductor. (22) A surface-emitting laser according to (21), wherein the III-V compound semiconductor is a GaN-based compound semiconductor. (23) A surface-emitting laser according to (21), wherein the III-V compound semiconductor is a GaAs-based compound semiconductor. (24) A surface-emitting laser according to (21), wherein the III-V compound semiconductor is an InP-based compound semiconductor. (25) An electronic device comprising a surface light-emitting element as described in any one of (1) to (24).

[0363] 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 160, 165, 170, 175, 180, 190, 200, 210, 220, 230, 240, 250, 260, 270, 280, 290, 300, 310, 320, 330, 340, 350, 360, 370, 380, 390, 400, 410, 420: Surface-emitting laser 101: Substrate 101a: First convex surface 101a1: Central part 101a2: Peripheral part 102: First reflector 103: Active layer 103a: Light-emitting region 107: Second reflector (plane mirror, concave mirror) 108: First reflecting mirror (concave mirror, plane mirror)

Claims

1. A surface-emitting laser comprising: a first reflective structure; a second reflective structure; and an intermediate structure containing an active layer sandwiched between the first reflective structure and the second reflective structure, wherein the first reflective structure has at least one convex surface that is convex on the side opposite to the second reflective structure, and has a reflectance distribution and / or reflection direction distribution in the in-plane direction.

2. The surface-emitting laser according to claim 1, wherein the first reflective structure has a first reflectance, which is the reflectance of the central part, and a second reflectance, which is the reflectance of the peripheral part, which are different.

3. The surface-emitting laser according to claim 2, wherein the active layer has a light-emitting region, and the central portion overlaps with the light-emitting region in a plan view.

4. The surface-emitting laser according to claim 2, wherein the second reflectance is lower than the first reflectance.

5. The surface-emitting laser according to claim 1, wherein the convex surface has a first roughness, which is the roughness of the central part, and a second roughness, which is the roughness of the peripheral part, which are different.

6. The surface-emitting laser according to claim 5, wherein the second roughness is higher than the first roughness.

7. The surface-emitting laser according to claim 1, wherein the convex surface has irregularities in its central or peripheral portion.

8. The surface-emitting laser according to claim 7, wherein the convex surface has the irregularities provided in its peripheral portion.

9. The surface-emitting laser according to claim 1, wherein the convex surface has an oxide film or a chloride film provided in the central or peripheral portion.

10. The surface-emitting laser according to claim 9, wherein the convex surface has the oxide film or the chloride film provided in its peripheral portion.

11. The surface-emitting laser according to claim 1, wherein the convex surface has a radius of curvature distribution in the in-plane direction.

12. The surface-emitting laser according to claim 11, wherein the radius of curvature of the convex surface is different at the center and at the periphery.

13. The surface-emitting laser according to claim 1, wherein the first reflective structure comprises a first convex surface as the convex surface, and a second convex surface as the convex surface, the second convex surface located on the opposite side of the first convex surface from the second reflective structure side.

14. The surface-emitting laser according to claim 13, wherein the first reflective structure includes a concave mirror having a concave surface along the first convex surface on the side of the first convex surface, and a second convex surface on the side opposite to the first convex surface.

15. The surface-emitting laser according to claim 14, wherein the intermediate structure includes a portion of a substrate disposed on the first reflective structure side of the active layer, and the first convex surface is at least a portion of the concave mirror side surface of the substrate.

16. The surface-emitting laser according to claim 1, wherein the first reflective structure includes a plane mirror and a substrate disposed on the side of the plane mirror opposite to the second reflective structure, the substrate having the convex surface on the side opposite to the second reflective structure.

17. The surface-emitting laser according to claim 16, wherein an anti-reflective coating is provided on the convex surface.

18. When the resonator length is L, the radius of curvature of the convex surface is R, the oscillation wavelength is λ, and the average refractive index of the region between the convex surface and the second reflective structure is n, the diameter of the central part is 3[(λ / πn)[LR] 2 (RL)] 1 / 2 ] 1 / 2 The surface-emitting laser according to claim 1.

19. The surface-emitting laser according to claim 1, wherein at least one of the first and second reflective structures includes a dielectric multilayer mirror.

20. The surface-emitting laser according to claim 1, wherein at least one of the first and second reflective structures includes a semiconductor multilayer mirror.

21. The surface-emitting laser according to claim 1, wherein the intermediate structure comprises a III-V compound semiconductor.

22. The surface-emitting laser according to claim 21, wherein the III-V compound semiconductor is a GaN-based compound semiconductor.

23. The surface-emitting laser according to claim 21, wherein the III-V compound semiconductor is a GaAs-based compound semiconductor.

24. The surface-emitting laser according to claim 21, wherein the III-V compound semiconductor is an InP-based compound semiconductor.

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