Optical element and surface-emitting laser

Abstract

To provide an optical element and a surface-emitting laser that can improve performance.SOLUTION: According to an embodiment, an optical element includes a first member including a first region along a first plane. The first region includes a plurality of first structures. The plurality of first structures are arranged at a first pitch along a first direction and at a second pitch along a second direction. The first direction is along the first plane. The second direction is along the first plane and intersects with the first direction. The first pitch is longer than the second pitch. A first length of the first region along the first direction is longer than a second length of the first region along the second direction.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] FIELD Embodiments of the present invention relate to an optical element and a surface-emitting laser. [Background technology]

[0002] For example, optical elements such as photonic crystals are used in surface-emitting lasers, and improvements in the characteristics of optical elements are desired. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2020-136557 Summary of the Invention [Problem to be solved by the invention]

[0004] The embodiments provide an optical element and a surface-emitting laser that can improve characteristics. [Means for solving the problem]

[0005] According to an embodiment, an optical element includes a first member including a first region along a first plane. The first region includes a plurality of first structures. The plurality of first structures are arranged at a first pitch along a first direction and at a second pitch along a second direction. The first direction is along the first plane. The second direction is along the first plane and intersects with the first direction. The first pitch is longer than the second pitch. A first length of the first region along the first direction is longer than a second length of the first region along the second direction. [Brief explanation of the drawings]

[0006] [Figure 1] FIG. 1 is a schematic plan view illustrating the optical element according to the first embodiment. [Figure 2] FIG. 2 is a schematic plan view illustrating a part of the optical element according to the first embodiment. [Figure 3] 3A and 3B are schematic cross-sectional views illustrating the optical element according to the first embodiment. [Figure 4] 4(a) to 4(d) are schematic diagrams illustrating the characteristics of optical elements. [Figure 5] 5(a) and 5(b) are schematic cross-sectional views illustrating the optical element according to the first embodiment. [Figure 6] FIG. 6 is a schematic cross-sectional view illustrating the surface-emitting laser according to the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0007] Hereinafter, embodiments of the present invention will be described with reference to the drawings. The drawings are schematic or conceptual, and the relationship between the thickness and width of each part, the size ratio between parts, etc. are not necessarily the same as those in reality. Even when the same part is shown, the dimensions and ratios may be different depending on the drawing. In this specification and in each drawing, elements similar to those previously described with reference to the previous drawings are designated by the same reference numerals, and detailed descriptions thereof will be omitted where appropriate.

[0008] (First embodiment) FIG. 1 is a schematic plan view illustrating the optical element according to the first embodiment. FIG. 2 is a schematic plan view illustrating a part of the optical element according to the first embodiment. 3A and 3B are schematic cross-sectional views illustrating the optical element according to the first embodiment. Fig. 3(a) corresponds to the cross section taken along the line A1-A2 in Fig. 1. Fig. 3(b) corresponds to the cross section taken along the line B1-B2 in Fig. 1.

[0009] 1, an optical element 10A according to this embodiment includes a first member 11. The first member 11 includes a first region 11A. The first region 11A is aligned along a first plane PL1.

[0010] The first plane PL1 is, for example, substantially parallel to the XY plane. The first direction D1 and the second direction D2 are aligned with the first plane PL1. The first direction D1 may be, for example, the X-axis direction.

[0011] A direction perpendicular to the X-axis direction is defined as the Y-axis direction. A direction perpendicular to the X-axis direction and the Y-axis direction is defined as the Z-axis direction. The Z-axis direction is perpendicular to the first plane PL1. In one example, the second direction D2 is the Y-axis direction.

[0012] 1, the first region 11A includes a plurality of first structural bodies 11S. As shown in Fig. 1, the plurality of first structural bodies 11S are aligned along a first direction D1 and a second direction D2.

[0013] 2 illustrates an enlarged portion of the first region 11A. The multiple first structures 11S are arranged at a first pitch p1 along a first direction D1. The multiple first structures 11S are arranged at a second pitch p2 along a second direction D2. The first pitch p1 is longer than the second pitch p2.

[0014] 1, the length of the first region 11A along the first direction D1 is defined as a first length L1. The length of the first region 11A along the second direction D2 is defined as a second length L2. In the embodiment, the first length L1 is longer than the second length L2.

[0015] As shown in Figures 3(a) and 3(b), the first member 11 may further include a first layer-like portion 11L. The multiple first structures 11S are continuous with the first layer-like portion 11L. The multiple first structures 11S protrude from the first layer-like portion 11L. The multiple first structures 11S include side surfaces 11SF. The side surfaces 11SF intersect with the first plane PL1.

[0016] The refractive index of the multiple first structures 11S is different from the refractive index of the space that the multiple first structures 11S face. The space may be air or the like. The space may be a member different from the first member 11. A refractive index difference is provided on the side surfaces 11SF of the multiple first structures 11S. The multiple side surfaces 11SF act on light incident on the multiple first structures 11S. The multiple first structures 11S function as, for example, a photonic crystal layer. The multiple first structures 11S are, for example, crystals.

[0017] For example, light is incident on optical element 10A at an arbitrary angle. The light is emitted in a direction including a component perpendicular to first plane PL1 due to the action of the multiple first structures 11S. For example, light has difficulty traveling in a direction along first plane PL1. Optical element 10A can, for example, control the emission direction of light.

[0018] As described above, in the embodiment, the first pitch p1 of the plurality of first structures 11S is longer than the second pitch p2. That is, anisotropy is provided in the pitch of the plurality of first structures 11S. Meanwhile, in the first region 11A where the plurality of first structures 11S are provided, the first length L1 is longer than the second length L2. That is, anisotropy is provided in the shape of the first region 11A. With this configuration, for example, it is possible to control the anisotropy of the cross-sectional shape of light acted upon by the optical element 10A. For example, it is possible to make the cross-sectional shape of the light beam acted upon by the optical element 10A isotropic, such as circular. Or, it is possible to make the cross-sectional shape approach isotropic, such as circular. According to the embodiment, it is possible to provide an optical element capable of improving characteristics. Examples of the characteristics of the optical element 10A are described below.

[0019] 4(a) to 4(d) are schematic diagrams illustrating the characteristics of optical elements. These illustrate the far-field pattern 11F of light acted upon by the optical element.

[0020] FIG. 4(a) corresponds to the first configuration CF1. In the first configuration CF1, the cross-sectional shape (planar shape) of one of the multiple first structures 11S is circular. The first pitch p1 is the same as the second pitch p2. The shape of the first region 11A is square. In this case, the far-field pattern 11F includes a main pattern and multiple sub-patterns around it. In the first configuration CF1, it is considered that such a far-field pattern 11F is generated by the influence of interference in multiple directions.

[0021] 4(b) corresponds to the second configuration CF2. In the second configuration CF2, the shape of one of the plurality of first structures 11S is the polygon illustrated in FIG. 2. The first pitch p1 is the same as the second pitch p2. The shape of the first region 11A is a square. In this case, too, the far-field pattern 11F includes a main pattern and a plurality of sub-patterns around it.

[0022] FIG. 4(c) corresponds to the third configuration CF3. In the third configuration CF3, the shape of one of the plurality of first structures 11S is the polygon exemplified in FIG. 2. The first pitch p1 is longer than the second pitch p2. The shape of the first region 11A is square. In this case, the far-field pattern 11F includes the main pattern, and the plurality of sub-patterns disappear. In the third configuration CF3, the far-field pattern 11F has an anisotropic shape. In the far-field pattern 11F, the horizontal length is longer than the vertical length.

[0023] FIG. 4(d) corresponds to the fourth configuration CF4. In the fourth configuration CF4, the shape of one of the plurality of first structures 11S is the polygon exemplified in FIG. 2. The first pitch p1 is longer than the second pitch p2. In the first region 11A, the first length L1 is longer than the second length L2. For example, the first region 11A has a flattened circular shape (see FIG. 1). In this case, the far-field pattern 11F includes the main pattern, and the plurality of sub-patterns disappear. The main pattern is substantially isotropic.

[0024] In this way, in the fourth configuration CF4, the cross-sectional shape of the light beam acted upon by the optical element can be made isotropic. Alternatively, the cross-sectional shape can be made closer to an isotropic shape. The fourth configuration CF4 corresponds to the embodiment. According to the embodiment, an optical element capable of improving characteristics can be provided.

[0025] For example, the first length L1 may be the maximum length of the first region 11A along the first direction D1. For example, the first length L1 may be the maximum length of the first region 11A along the first direction D1.

[0026] 1, the first member 11 may further include a second region 11B. The second region 11B is provided around the first region 11A on the first plane PL1. The plurality of first structures 11S are not provided in the second region 11B.

[0027] In the embodiment, the ratio of the first pitch p1 to the second pitch p2 is defined as the first ratio. The ratio of the first length L1 to the second length L2 is defined as the second ratio. The first ratio may be substantially the same as the second ratio. For example, the first ratio may be 0.8 to 1.2 times the second ratio. This reduces the anisotropy in the cross-sectional shape of the light beam affected by the optical element.

[0028] As shown in FIG. 4, the far-field pattern 11F of light acted upon by the optical element 10A includes a first pattern length LF1 along the first direction D1 and a second pattern length LF2 along the second direction D2. The ratio of the first pattern length LF1 to the second pattern length LF2 (third ratio) is lower than the ratio of the first pitch p1 to the second pitch p2 (first ratio). In one example, the third ratio is, for example, not less than 0.8 and not more than 1.2. For example, a substantially isotropic light beam is obtained.

[0029] In the embodiment, the angle between the first direction D1 and the second direction D2 may be equal to or greater than 80 degrees and equal to or less than 100 degrees. The plurality of first structures 11S may be arranged in, for example, a rectangular lattice pattern.

[0030] In the embodiment, at least a part of the outer edge of the first region 11A may be curved. For example, the shape of the first region 11A may be a flattened circle (including an ellipse).

[0031] 1, the multiple first structures 11S include a first group G1 aligned along the second direction D2 and a second group G2 aligned along the second direction D2. The direction from the first group G1 to the second group G2 is from the center 11C of the first region 11A to the outside of the first region 11A. The number of multiple first structures 11S included in the second group G2 is smaller than the number of multiple first structures 11S included in the first group G1.

[0032] 1, the multiple first structures 11S include a third group G3 aligned along the first direction D1 and a fourth group G4 aligned along the first direction D1. The direction from the third group G3 to the fourth group G4 is from the center 11C of the first region 11A to the outside of the first region 11A. The number of the multiple first structures 11S included in the fourth group G4 is smaller than the number of the multiple first structures 11S included in the third group G3.

[0033] A second number of the plurality of first structures 11S arranged along the second direction D2 decreases along the first direction D1 from the center 11C of the first region 11A toward the outside of the first region 11A. A first number of the plurality of first structures 11S arranged along the first direction D1 decreases along the second direction D2 from the center 11C toward the outside.

[0034] In the embodiment, the cross-sectional shape of one of the first structures 11S along the first plane PL1 may be a circle, a flattened circle, or a polygon. The cross-sectional shape of the first structures 11S can be variously modified.

[0035] In the embodiment, it is more preferable that the cross-sectional shape of the plurality of first structures 11S is an anisotropic shape, which makes it easier to obtain a more uniform far-field pattern 11F.

[0036] 2, the cross-sectional shape (planar shape) of one of the multiple first structures 11S is an anisotropic pentagon. For example, the cross-sectional shape of one of the multiple first structures 11S along the first plane PL1 is asymmetric with respect to a first line Ln1 along the first direction D1 and a second line Ln2 along the second direction D2.

[0037] In the example shown in FIG. 2, the cross-sectional shape of one of the multiple first structures 11S includes a first side s1, a second side s2, a third side s3, a fourth side s4, and a fifth side s5. The first side s1 and the third side s3 are aligned along the first direction D1. The second side s2 and the fourth side s4 are aligned along the second direction D2. The fifth side s5 is inclined with respect to the first direction D1 and the second direction D2. The direction from the first side s1 to the third side s3 is aligned along the second direction D2. The direction from the second side s2 to the fourth side s4 is aligned along the first direction D1. The first side s1 connects the second side s2 to the fourth side s4. The third side s3 connects the second side s2 to the fifth side s5. The fourth side s4 connects the first side s1 to the fifth side s5. Such a shape makes it easier to obtain a far field pattern 11F with higher isotropy.

[0038] 5(a) and 5(b) are schematic cross-sectional views illustrating the optical element according to the first embodiment. Fig. 5(a) is a cross-sectional view corresponding to the cross section taken along the line A1-A2 in Fig. 1. Fig. 5(b) is a cross-sectional view corresponding to the cross section taken along the line B1-B2 in Fig. 1. 5(a) and 5(b), the optical element 10B according to the embodiment includes a second member 12 in addition to a first member 11. The remaining configuration of the optical element 10B may be similar to that of the optical element 10A. For example, in the optical element 10B as well, the first pitch p1 is longer than the second pitch p2. The first length L1 is longer than the second length L2.

[0039] As shown in FIGS. 5(a) and 5(b), in the optical element 10A, the second member 12 includes a first partial region 12a. The first partial region 12a is provided between a plurality of first structures 11S. The second refractive index of the second member 12 is different from the first refractive index of the first member 11. The first member 11 and the second member 12 form a photonic crystal structure. The optical element 10A can also provide highly isotropic light.

[0040] For example, the second member 12 contacts the first member 11. The second member 12 may further include a second partial region 12b. The direction from the plurality of first structures 11S to the second partial region 12b is along a third direction D3 that intersects with the first plane PL1, and the third direction D3 is, for example, the Z-axis direction. By providing the second member 12, for example, it becomes easier to stably maintain the shape and characteristics of the first member 11.

[0041] Each of the first member 11 and the second member 12 may include a crystal. The crystal lattice of the second member 12 may be continuous with the crystal lattice of the first member 11.

[0042] For example, a layer that will become the first member 11 is formed, and then the layer is patterned to obtain the first member 11. A layer that will become the second member 12 is formed on the first member 11, to obtain the second member 12.

[0043] In this embodiment, the first pitch p1 is, for example, 1.644 μm. The second pitch p2 is, for example, 1.37 μm. In one example shown in FIG. 2, the length of the first side s1 is 1.348 μm. The length of the second side s2 is 1.348 μm. The length of the third side s3 is 0.405 μm. The length of the fourth side s4 is, for example, 0.337 μm. In this example, the second side s2 is perpendicular to the first side s1. The fourth side s4 is perpendicular to the first side s1. The third side s3 is perpendicular to the second side s2. These values ​​are examples, and various modifications are possible.

[0044] (Second embodiment) FIG. 6 is a schematic cross-sectional view illustrating the surface-emitting laser according to the second embodiment. 6, the surface-emitting laser 110 according to the embodiment includes the optical element 10B according to the first embodiment, a first electrode 51, a second electrode 52, a first cladding layer 21, and a light-emitting layer 25. The first cladding layer 21 is provided between the first electrode 51 and the second electrode 52. The light-emitting layer 25 is provided between a portion 21p of the first cladding layer 21 and the second electrode 52. The optical element 10B is provided between the light-emitting layer 25 and the second electrode 52. The first member 11 is provided between the light-emitting layer 25 and the second member 12. The second refractive index is lower than the first refractive index.

[0045] In the surface-emitting laser 110, the second member 12 may function as a second cladding layer.

[0046] In the surface-emitting laser 110, light is emitted from the light-emitting layer 25 by a current supplied between the first electrode 51 and the second electrode 52. The traveling direction of the light is controlled by the optical element 10B, and the light is emitted to the outside via the first cladding layer 21. The emitted light 81L from the surface-emitting laser 110 includes a component along the Z-axis direction. The planar emitted light 81L is emitted.

[0047] 6, the surface-emitting laser 110 may include a substrate 10s. The first cladding layer 21 is provided between the substrate 10s and the light-emitting layer 25. Emitted light 81L is emitted from a substrate surface 10f of the substrate 10s.

[0048] For example, the light emitting layer 25 emits light due to intersubband transitions. The surface emitting laser 110 may be, for example, a surface emitting quantum cascade laser (QCL).

[0049] When the light-emitting layer 25 has a substantially single wavelength, the far-field pattern 11F described with reference to Figures 4(a) to 4(d) occurs. For example, when a quantum cascade laser or the like is combined with a photonic crystal layer, the sub-patterns described with reference to Figures 4(a) and 4(b) occur. By applying the optical element 10B according to the embodiment, isotropic light can be easily obtained in the surface-emitting laser 110.

[0050] The surface-emitting laser 110 may be applied to, for example, an analytical device. In the analytical device, the traveling direction of a light beam is controlled by a mirror or the like. For example, light scanning is performed. In such an example, if the cross section of the light beam has an anisotropic shape, it is not easy to control the traveling direction while maintaining the desired shape of the light beam. In the embodiment, the cross section of the emitted light 81L from the surface-emitting laser 110 is highly isotropic. This makes it easy to maintain the desired high-speed characteristics even when the traveling direction is controlled using a mirror or the like. According to the embodiment, a surface-emitting laser capable of improving characteristics can be provided.

[0051] As shown in FIG. 6 , the surface-emitting laser 110 may further include a reflective film 31. The direction from the light emitting layer 25 to the reflective film 31 is along the first plane PL1. The reflectance of the reflective film 31 at the wavelength of light emitted from the light emitting layer 25 is higher than the reflectance of the first cladding layer 21 at that wavelength. The reflectance of the reflective film 31 at the wavelength of light emitted from the light emitting layer 25 is higher than the reflectance of the second member 12 (the second cladding layer) at that wavelength. The reflective film 31 may be continuous with the second electrode 52.

[0052] 6, the surface-emitting laser 110 may further include an insulating film 31i. At least a part of the insulating film 31i is provided between the light-emitting layer 25 and the reflective film 31.

[0053] In one example, the first component 11 includes In, Ga, and As. The second component 12 includes In and P. The first cladding layer 21 includes In and P.

[0054] 4(d), the far-field pattern 11F of light passing through the first cladding layer 21 includes a first pattern length LF1 along the first direction D1 and a second pattern length LF2 along the second direction D2. The ratio of the first pattern length LF1 to the second pattern length LF2 is lower than the ratio of the first pitch p1 to the second pitch p2.

[0055] In the surface-emitting laser 110, the angle between the first direction D1 and the second direction D2 may be 80 degrees or more and 100 degrees or less, or may be 85 degrees or more and 90 degrees or less.

[0056] The embodiments may include the following technical solutions. (Technical proposal 1) a first member including a first region along a first plane; the first region includes a plurality of first structures; the plurality of first structures are arranged at a first pitch along a first direction and at a second pitch along a second direction; the first direction is along the first plane, the second direction is along the first plane and intersects with the first direction; the first pitch is longer than the second pitch; An optical element, wherein a first length of the first region along the first direction is longer than a second length of the first region along the second direction.

[0057] (Technical proposal 2) the first member further includes a second region; the second region is provided around the first region on the first plane, The optical element described in Technical Solution 1, wherein the plurality of first structures are not provided in the second region.

[0058] (Technical proposal 3) The optical element described in Technical Solution 1 or 2, wherein a first ratio of the first pitch to the second pitch is 0.8 to 1.2 times the second ratio of the first length to the second length.

[0059] (Technical proposal 4) The optical element according to any one of Technical Solutions 1 to 3, wherein the cross-sectional shape of one of the plurality of first structures along the first plane is a circle, a flattened circle, or a polygon.

[0060] (Technical proposal 5) An optical element described in any one of Technical Solutions 1 to 3, wherein the cross-sectional shape of one of the plurality of first structures along the first plane is asymmetric with respect to a first line along the first direction and a second line along the second direction.

[0061] (Technical proposal 6) The optical element according to any one of Technical Solutions 1 to 5, wherein the plurality of first structures are crystals.

[0062] (Technical proposal 7) The optical element according to any one of Technical Solutions 1 to 6, wherein the first member is at least a part of a photonic crystal.

[0063] (Technical proposal 8) a second number of the plurality of first structures aligned along the second direction decreases from a center of the first region to an outside of the first region along the first direction; An optical element described in any one of Technical Solutions 1 to 7, wherein the first number of the plurality of first structures arranged along the first direction decreases in the direction from the center to the outside along the second direction.

[0064] (Technical proposal 9) the plurality of first structures include a first group aligned along the second direction and a second group aligned along the second direction, the direction from the first group to the second group is from the center of the first region to the outside of the first region, The optical element described in any one of Technical Solutions 1 to 7, wherein the number of the plurality of first structures included in the second group is smaller than the number of the plurality of first structures included in the first group.

[0065] (Technical proposal 10) The optical element according to any one of Technical Solutions 1 to 9, wherein at least a part of the outer edge of the first region is curved.

[0066] (Technical proposal 11) a second member including a first partial region; the first partial region is provided between the plurality of first structures, The optical element according to any one of Technical Solutions 1 to 10, wherein the second refractive index of the second member is different from the first refractive index of the first member.

[0067] (Technical proposal 12) The optical element described in Technical Solution 11, wherein the second member is in contact with the first member.

[0068] (Technical proposal 13) the second member further includes a second partial region; The optical element described in Technical Solution 11 or 12, wherein the direction from the plurality of first structures to the second partial region is along a third direction that intersects with the first plane.

[0069] (Technical proposal 14) An optical element according to any one of Technical Schemes 11 to 13; A first electrode; A second electrode; a first clad layer provided between the first electrode and the second electrode; a light-emitting layer provided between a portion of the first cladding layer and the second electrode; Equipped with the optical element is provided between the light emitting layer and the second electrode, the first member is provided between the light-emitting layer and the second member, The second refractive index is lower than the first refractive index.

[0070] (Technical proposal 15) Further comprising a reflective film; a direction from the light-emitting layer to the reflective film is along the first plane; A surface-emitting laser according to Technical Solution 14, wherein the reflectivity of the reflective film at the wavelength of light emitted from the light-emitting layer is higher than the reflectivity of the first cladding layer at the wavelength.

[0071] (Technical proposal 16) The surface-emitting laser according to Technical Solution 15, further comprising an insulating film provided between the light-emitting layer and the reflective film.

[0072] (Technical proposal 17) The surface-emitting laser according to Technical Solution 14 or 16, wherein the light-emitting layer emits light by intersubband transition.

[0073] (Technical proposal 18) the first component includes In, Ga, and As; the second component includes In and P; 18. The surface-emitting laser according to any one of Technical Solutions 14 to 17, wherein the first cladding layer contains In and P.

[0074] (Technical proposal 19) a far-field pattern of the light passing through the first cladding layer and exiting the first cladding layer includes a first pattern length along the first direction and a second pattern length along the second direction; 19. The surface-emitting laser according to any one of Technical Solutions 14 to 18, wherein a ratio of the first pattern length to the second pattern length is lower than a ratio of the first pitch to the second pitch.

[0075] (Technical proposal 20) 20. The surface-emitting laser according to any one of Technical Schemes 14 to 19, wherein the angle between the first direction and the second direction is equal to or greater than 80 degrees and equal to or less than 100 degrees.

[0076] According to the embodiment, it is possible to provide an optical element and a surface-emitting laser that can improve characteristics.

[0077] In this specification, "vertical" and "parallel" do not only mean strictly vertical and strictly parallel, but also include variations in the manufacturing process, and may mean substantially vertical and substantially parallel.

[0078] The embodiments of the present invention have been described above with reference to specific examples. However, the present invention is not limited to these specific examples. For example, the specific configurations of the components, electrodes, cladding layers, light-emitting layers, and other elements included in the optical element and surface-emitting laser are within the scope of the present invention as long as a person skilled in the art can implement the present invention in a similar manner and obtain similar effects by appropriately selecting them from known ranges.

[0079] Furthermore, any combination of two or more elements of each specific example within the scope of technical feasibility is also included within the scope of the present invention as long as it includes the gist of the present invention.

[0080] In addition, all optical elements and surface-emitting lasers that can be implemented by a person skilled in the art by appropriately modifying the design based on the optical elements and surface-emitting lasers described above as embodiments of the present invention also fall within the scope of the present invention, as long as they include the gist of the present invention.

[0081] In addition, within the scope of the concept of the present invention, a person skilled in the art may come up with various modifications and alterations, and it will be understood that these modifications and alterations also fall within the scope of the present invention.

[0082] Although several embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be embodied in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, and are also included in the scope of the invention and its equivalents as defined in the claims. [Explanation of symbols]

[0083] 10A, 10B: optical element, 10f: substrate surface, 10s: substrate, 11, 12: first and second members, 11A, 11B: first and second regions, 11C: center, 11F: far-field pattern, 11L: first layered portion, 11S: first structure, 11SF: side surface, 12a, 12b: first and second partial regions, 21: first cladding layer, 21p: part, 25: light-emitting layer, 31: reflective film, 31i: insulating film, 51, 52: first and second electrodes, 81L: emitted light, 110: surface-emitting laser, CF1 to CF4: first to fourth structures, D1 to D3: first to third directions, G1 to G4: first to fourth groups, L1, L2: first and second lengths, LF1, LF2: 1st and 2nd pattern lengths, Ln1, Ln2: 1st and 2nd lines, PL1: 1st plane, p1, p2: 1st and 2nd pitches, s1 to s5: 1st to 5th sides

Claims

1. a first member including a first region along a first plane; the first region includes a plurality of first structures; the plurality of first structures are arranged at a first pitch along a first direction and at a second pitch along a second direction; the first direction is along the first plane; the second direction is along the first plane and intersects with the first direction; the first pitch is longer than the second pitch; An optical element, wherein a first length of the first region along the first direction is longer than a second length of the first region along the second direction.

2. the first member further includes a second region; the second region is provided around the first region in the first plane, The optical element according to claim 1 , wherein the plurality of first structures are not provided in the second region.

3. 2. The optical element according to claim 1, wherein a first ratio of the first pitch to the second pitch is 0.8 to 1.2 times a second ratio of the first length to the second length.

4. 4. The optical element according to claim 1, wherein a cross-sectional shape of one of the plurality of first structures along the first plane is a circle, a flattened circle, or a polygon.

5. An optical element described in any one of claims 1 to 3, wherein a cross-sectional shape of one of the plurality of first structures along the first plane is asymmetric with respect to a first line along the first direction and a second line along the second direction.

6. a second number of the plurality of first structures aligned along the second direction decreases in a direction from a center of the first region to an outside of the first region along the first direction; The optical element according to claim 1 , wherein a first number of the plurality of first structures aligned along the first direction decreases in a direction from the center to the outside along the second direction.

7. the plurality of first structures include a first group aligned along the second direction and a second group aligned along the second direction, the direction from the first group to the second group is a direction from the center of the first region to the outside of the first region, The optical element according to claim 1 , wherein the number of the first structures included in the second group is smaller than the number of the first structures included in the first group.

8. a second member including a first partial region; the first partial region is provided between the plurality of first structures, The optical element according to claim 1 , wherein the second refractive index of the second member is different from the first refractive index of the first member.

9. the second member further includes a second partial region; The optical element according to claim 8 , wherein a direction from the plurality of first structures to the second partial region is along a third direction intersecting the first plane.

10. The optical element according to claim 8; A first electrode; A second electrode; a first clad layer provided between the first electrode and the second electrode; a light-emitting layer provided between a portion of the first cladding layer and the second electrode; Equipped with the optical element is provided between the light emitting layer and the second electrode, the first member is provided between the light-emitting layer and the second member, The second refractive index is lower than the first refractive index.

11. 11. The surface-emitting laser according to claim 10, wherein the light-emitting layer emits light due to intersubband transition.

12. a far-field pattern of the light passing through the first cladding layer and exiting the first cladding layer includes a first pattern length along the first direction and a second pattern length along the second direction; 12. The surface-emitting laser according to claim 10, wherein a ratio of the first pattern length to the second pattern length is lower than a ratio of the first pitch to the second pitch.

Images