Spatial light modulator and light emitting device

Abstract

The present disclosure relates to a spatial light modulator and the like having a structure in which a phase distribution of light can be dynamically controlled and a pitch of pixels is smaller and suitable for high-speed operation. The spatial light modulator has a substrate. The substrate has a surface, a back surface, and a plurality of through-holes arranged in one dimension or two dimensions and penetrating between the surface and the back surface. The spatial light modulator also has a plurality of layered structures respectively covering inner walls of the plurality of through-holes. Each layered structure includes a first conductive layer provided on the inner wall, a dielectric layer provided on the first conductive layer and having light transmissivity, and a second conductive layer provided on the dielectric layer and having light transmissivity. At least one of the first and second conductive layers is electrically separated for each group consisting of one or more through-holes.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a spatial light modulator and a light emitting device. BACKGROUND

[0002] In Patent Literature 1, a technology relating to a semiconductor light emitting element and a manufacturing method thereof is disclosed. The semiconductor light emitting element has a semiconductor substrate, and a first cladding layer, an active layer, a second cladding layer, and a contact layer which are sequentially provided on the semiconductor substrate, respectively. Further, the semiconductor light emitting element has a phase modulation layer which is located between the first cladding layer and the active layer or between the active layer and the second cladding layer. The phase modulation layer has a base layer, and a plurality of difference refractive index regions having a refractive index different from that of the base layer. A virtual square lattice on a plane perpendicular to a thickness direction of the phase modulation layer is composed of a plurality of unit structure regions. The difference refractive index regions are allocated to each unit structure region, and the phase modulation layer is configured such that a barycentric position of the difference refractive index regions is arranged to deviate from a lattice point of the corresponding unit structure region, and has a rotation angle around the lattice point corresponding to a desired optical image.

[0003] In Non Patent Literature 1, it is described that a plurality of periodic recesses are formed on a substrate surface by MACE (Metal-Assisted Chemical Etching), and a phase of incident light is modulated by laminating a metal layer, a dielectric layer, and a transparent conductive layer on a side wall of the recess.

[0004] Prior Art Documents

[0005] Patent Literature

[0006] Patent Literature 1: Japanese Patent Application Publication No. 2018-198302

[0007] Non Patent Literature

[0008] Non Patent Literature 1: Junghyun Park and Soo Jin Kim, "Subwavelength-spaced transmissive metallic slits for 360-degree phase control by using transparent conducting oxides", Applied Optics, Vol. 57, No. 21, 6027-6031, 20 July 2018

[0009] Non Patent Literature 2: Appl. Opt. No. 5, p. 967-969 (1966)

[0010] Non-Patent Literature 3: Appl. Opt. No. 9, p. 1949 (1970)

[0011] Non-Patent Literature 4: Y. Kurosaka et al., "Effects of non-lasing band in two-dimensional photonic-crystal lasers clarified using omnidirectional bandstructure," Opt. Express 20, 21773-21783 (2012) SUMMARY

[0012] PROBLEMS TO BE SOLVED BY THE INVENTION

[0013] The present inventors have conducted research on the above-described related art and have found the following problems. That is, research has been conducted on a technique for generating an arbitrary optical image by spatial phase modulation. In a certain technique, a phase modulation layer including a plurality of regions of different refractive index is provided near an active layer of a semiconductor laser element. Furthermore, in a virtual square lattice set on a plane perpendicular to the thickness direction of the phase modulation layer, for example, the centers of gravity of the plurality of regions of different refractive index are arranged to deviate from the lattice points of the virtual square lattice, and the rotation angle around the lattice points is individually set for each region of different refractive index. Such an element can emit laser light in the stacking direction as with a photonic crystal laser element, and can control the phase distribution of the laser light in space to emit the laser light as an arbitrary optical image.

[0014] However, the arrangement of the plurality of regions of different refractive index of the phase modulation layer of the above-described element is fixed, and thus only one kind of optical image designed in advance can be emitted. In order to dynamically change the emitted optical image, the phase distribution of the emitted light needs to be dynamically controlled.

[0015] As a device capable of dynamically controlling the phase distribution of light, there is a spatial light modulator of the phase modulation type. For example, a liquid crystal type spatial light modulator has a structure in which a plurality of pixel electrodes are arranged one-dimensionally or two-dimensionally along a liquid crystal layer. Furthermore, the amount of phase modulation of light incident on the liquid crystal layer can be controlled individually for each pixel by individually setting the voltage for each pixel electrode. By combining such a spatial light modulator with a surface light source (for example, a photonic crystal laser element), the phase distribution of the emitted light can be dynamically controlled.

[0016] However, the arrangement period of the pixels of the liquid crystal type spatial light modulator is on the order of 10 μm, in contrast to which the size of the light emitting surface of the photonic crystal laser element is 200 μm to 500 μm in each side length. Therefore, even if the liquid crystal type spatial light modulator is combined with the photonic crystal laser element, the number of effective pixels is extremely small, and it is difficult to obtain an optical image of high quality. Also, the operation speed is limited by the response speed of the liquid crystal, and thus there is a problem in that it is difficult to speed up.

[0017] The present disclosure was made in order to solve the above problem, and aims to provide a spatial light modulator capable of dynamically controlling the phase distribution of light and having a smaller arrangement period of pixels and suitable for speeding up, and a light emitting device provided with the spatial light modulator.

[0018] Technical means for solving the problem

[0019] The spatial light modulator of one embodiment of the present disclosure includes a spatial light modulator of a surface waveguide type. The spatial light modulator includes a substrate and a plurality of stacked structures. The substrate has a surface, a back surface opposite to the surface, and a plurality of through holes that respectively communicate the surface and the back surface. Further, each opening defined on the surface of the plurality of through holes is arranged in one dimension or two dimensions. In particular, the plurality of stacked structures respectively include a first conductive layer, a dielectric layer, and a second conductive layer. The first conductive layer is provided on an inner wall of a corresponding through hole of the plurality of through holes. The dielectric layer is provided on the first conductive layer and has light transmittance. The second conductive layer is provided on the dielectric layer and has light transmittance. Further, at least one of the first and second conductive layers is electrically separated for each group consisting of one or more through holes of the plurality of through holes.

[0020] Effects of the Invention

[0021] According to the present disclosure, a spatial light modulator capable of dynamically controlling the phase distribution of light and having a smaller arrangement period of pixels and suitable for speeding up, and a light emitting device provided with the spatial light modulator can be provided. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 is a cross-sectional perspective view showing the appearance of a spatial light modulator 1A of a first embodiment, and is a view showing a part of the spatial light modulator 1A in an enlarged manner.

[0023] Figure 2 (a) to (i) are views showing examples of the shape of each through hole 13 viewed in the thickness direction of the substrate 10.

[0024] Figure 3 is a cross-sectional perspective view showing the appearance of a spatial light modulator 1A of a first embodiment, and is a view showing a part of the spatial light modulator 1A in an enlarged manner. Figure 1The cross-sectional view of the III-III line shown is a view showing a side cross section of the spatial light modulator 1A.

[0025] Figure 4 is a partial enlarged view of Figure 3

[0026] Figure 5 is a view explaining the operation of the spatial light modulator 1A.

[0027] Figure 6 is a view conceptually showing the form of light L in a case where a gradient is imparted to the magnitude of the voltage between the conductive layer 21 and the conductive layer 23 in a plurality of through holes 13 arranged in a certain direction.

[0028] Figure 7 (a) to (d) are views showing one example of a method of manufacturing the spatial light modulator 1A.

[0029] Figure 8 (a) to (d) are views showing one example of a method of manufacturing the spatial light modulator 1A.

[0030] Figure 9 (a) to (c) are views showing one example of a method of manufacturing the spatial light modulator 1A.

[0031] Figure 10 (a) to (c) are views showing one example of a method of manufacturing the spatial light modulator 1A.

[0032] Figure 11 (a) to (c) are views showing another method (MACE) of forming a plurality of through holes 13 in the substrate 10.

[0033] Figure 12 is a plan view showing the spatial light modulator IB as a first modification example.

[0034] Figure 13 is a plan view showing the spatial light modulator 1C as a second modification example.

[0035] Figure 14 is a plan view showing the spatial light modulator ID as a second modification example.

[0036] Figure 15 is a plan view showing the spatial light modulator IE as a second modification example.

[0037] Figure 16 is a plan view showing the spatial light modulator IF as a third modification example.

[0038] Figure 17 is a cross-sectional view showing the structure of the spatial light modulator 1G as a fourth modification example. ​

[0039] Figure 18 (a) and Figure 18 (b) is a view showing a step of forming the dielectric region 28 in a step of manufacturing the spatial light modulator 1G.

[0040] Figure 19 is a cross-sectional view showing a structure of the spatial light modulator 1H as a fifth modification example.

[0041] Figure 20 (a) to (c) are views for explaining a structure of a basic element and a basic unit for realizing dynamic modulation of phase in the spatial light modulators 1A to 1H.

[0042] Figure 21 (a) is a cross-sectional view showing a structure of the light-emitting device 2 of the second embodiment. Figure 21 (b) is a cross-sectional view showing the photonic crystal layer 65A enlarged.

[0043] Figure 22 is a plan view of the photonic crystal layer 65A.

[0044] Figure 23 is a cross-sectional view showing one modification example of the light-emitting device 2 of the second embodiment.

[0045] Figure 24 is a view showing an example of a planar shape of the metal electrode film 66 and the bonding portion 51.

[0046] Figure 25 is a cross-sectional view showing a structure in a case where the semiconductor substrate 53 is removed from the structure shown in Figure 23 .

[0047] Figure 26 is a plan view of the phase modulation layer 65B provided in the S-iPM laser.

[0048] Figure 27 is a plan view showing other examples of a shape of the differential refractive index region in the X-Y plane.

[0049] Figure 28 is a view for explaining a relationship between an optical image obtained by imaging an output beam pattern of the surface-emitting laser element 50 and a distribution of the rotation angle of the phase modulation layer 65B. .

[0050] Figure 29 is a view for explaining a coordinate transformation from the spherical coordinates (r, θ rot , θ tilt ) to the coordinates (ξ, η, ζ) in the XYZ orthogonal coordinate system.

[0051] Figure 30 (a) andFigure 30 (b) is a diagram for explaining a point to be noted in a case where a general discrete Fourier transform (or a fast Fourier transform) is used for calculation when the configuration of the difference refractive index regions 65b is determined.

[0052] Figure 31 is a diagram conceptually showing one example of a rotation angle distribution

[0053] Figure 32 is a plan view of a phase modulation layer 65C provided to an S-iPM laser.

[0054] Figure 33 is a diagram showing the positional relationship of the difference refractive index regions 65b of the phase modulation layer 65C. DETAILED DESCRIPTION

[0055] [Explanation of Embodiments of the Present Disclosure]

[0056] First, the content of the embodiments of the present disclosure is explained individually.

[0057] (1) The spatial light modulator of the present disclosure includes a spatial light modulator of a slab waveguide type. The spatial light modulator, as one mode, has a substrate and a plurality of layer structures. The substrate has a surface, a back surface opposite to the surface, and a plurality of through holes respectively communicating the surface and the back surface. In addition, each opening defined on the surface of the plurality of through holes is configured in one-dimensional or two-dimensional. In particular, the plurality of layer structures respectively include a first conductive layer, a dielectric layer, and a second conductive layer. The first conductive layer is provided on the inner wall of the corresponding through hole among the plurality of through holes. The dielectric layer is provided on the first conductive layer and has optical transmittance. The second conductive layer is provided on the dielectric layer and has optical transmittance. And, at least one of the first and second conductive layers is electrically separated for each group consisting of one or more through holes among the plurality of through holes.

[0058] ​When light is incident from the surface side or the back side with respect to the spatial light modulator, the light passes through the plurality of through-holes. At this time, the light in each through-hole travels while being reflected at the interface between the first conductive layer and the dielectric layer of each layered structure, and passes through each through-hole. When a voltage is applied between the first conductive layer and the second conductive layer, the refractive index of the second conductive layer changes depending on the density of the carriers accumulated in the second conductive layer, and in addition, the refractive index of the dielectric layer changes by the electric field between the first conductive layer and the second conductive layer, and in addition, the phase shift amount before and after reflection at the interface between the first conductive layer and the dielectric layer changes. Thus, the phase of the light exiting from each through-hole changes depending on the magnitude of the voltage between the first conductive layer and the second conductive layer. Also, at least one of the first and second conductive layers is electrically separated for each group of one or more through-holes. Therefore, it is possible to individually set the voltage for each or two or more through-holes. By the above effects, according to the spatial light modulator, it is possible to dynamically control the phase distribution of light.

[0059] In addition, since the through-holes can be formed by, for example, an etching process of a semiconductor or metal-assisted chemical etching (MACE), or the like, it is possible to easily make the arrangement period of the through-holes smaller than the arrangement period of the pixels of the liquid crystal type spatial light modulator. Therefore, according to the spatial light modulator, it is possible to reduce the arrangement period of the pixels compared to the related art. As a result, by combining the spatial light modulator with a surface light source such as a photonic crystal laser element, it is possible to increase the number of effective pixels and obtain an optical image of high quality. In addition, since the spatial light modulator does not use liquid crystals, it is not limited by the reaction speed of the liquid crystals, and is suitable for high speed.

[0060] (2) As one embodiment of the present disclosure, it is preferable that the opening shape of each of the plurality of through-holes defined on the surface has rotational symmetry or mirror symmetry. In addition, as one embodiment of the present disclosure, it can also be that the opening shape of each of the plurality of through-holes defined on the surface is identical to each other.

[0061] (3) As one embodiment of the present disclosure, it is preferable that the opening center of gravity of each of the plurality of through-holes is located at a lattice point of a square lattice or a triangular lattice at least one of the surface and the back surface. In this case, the plurality of through-holes are regularly arranged on a plane perpendicular to the thickness direction of the substrate, and thus it is possible to easily design an optical image.

[0062] (4) As one embodiment of the present disclosure, it can also be that the opening shape of each of the plurality of through-holes defined on the surface is a shape extending in a linear shape. At this time, the plurality of through-holes can also be arranged in a direction intersecting the extension direction of each of the through-holes.

[0063] (5) As one embodiment of the present disclosure, the opening shape of each of the plurality of through holes can include a linear shape or a circular arc shape.

[0064] (6) As one embodiment of the present disclosure, in a case where the opening shape of each of the plurality of through holes includes a circular arc shape extending across an angle range smaller than 360° in a polar coordinate with an origin as a center, the plurality of through holes are preferably arranged at equal intervals in a radial direction on the surface.

[0065] (7) As one embodiment of the present disclosure, the spatial light modulator can further include, at each of the plurality of through holes, a dielectric region provided on the corresponding one of the plurality of stacked structures and having optical transmittance. In this case, the optical path length of light within the through hole is increased, and the number of times of reflection of light at the interface between the first conductive layer and the dielectric layer is increased. Thus, the amount of phase modulation of each through hole can be increased. Alternatively, the thickness of the substrate required to achieve a predetermined amount of phase modulation can be reduced.

[0066] (8) As one embodiment of the present disclosure, the dielectric region preferably fills at least a predetermined range defined in a thickness direction from the surface toward the back surface in a space surrounded by the corresponding one of the plurality of stacked structures. In this case, the optical path length of light within the through hole is further increased, and the number of times of reflection of light at the interface between the first conductive layer and the dielectric layer is further increased.

[0067] (9) As one embodiment of the present disclosure, the spatial light modulator can further include, at each of the plurality of through holes, a smoothing layer provided on the inner wall and having a smooth surface, and the corresponding one of the plurality of stacked structures can be provided on the surface of the smoothing layer. In this case, since the surface of the first conductive layer is smooth even in a case where there is unevenness on the inner wall of the through hole, diffuse reflection of light can be suppressed. In addition, in a case where the smoothing layer is composed of a dielectric having insulation, the first conductive layer and the substrate can be electrically separated from each other, and thus unnecessary leakage of current to the substrate can be suppressed.

[0068] (10) As one embodiment of the present disclosure, the smoothing layer can include at least one of a metal and a dielectric. In this case, the smoothing layer can be appropriately implemented.

[0069] (11) As one embodiment of the present disclosure, one of the first and second conductive layers can be electrically connected to one or more first electrodes provided on the surface of the substrate corresponding to each of the plurality of through holes. With such a configuration, for example, it is possible to apply a voltage to each of the first and second conductive layers individually for each through hole. In addition, as one embodiment of the present disclosure, it is preferable that the other of the first and second conductive layers be electrically connected to a second electrode provided on the back surface of the substrate in common to the plurality of through holes. With such a configuration, for example, it is possible to easily set a potential serving as a reference for the first or second conductive layer.

[0070] (12) As one embodiment of the present disclosure, it is preferable that the second electrode cover the region between the plurality of through holes on the surface or the back surface of the substrate. In this case, since it is possible to suppress light passing through the substrate other than the through holes, the outgoing light can be composed only of light modulated by the through holes. In addition, by providing such a second electrode on the surface and the back surface of the substrate on the side on which light is incident, it is possible to suppress light absorption of the substrate other than the through holes and suppress an increase in the temperature of the substrate.

[0071] (13) As one embodiment of the present disclosure, the spatial light modulator having the above-described configuration can include a structure that realizes dynamic modulation of the phase of incident light by intensity modulation of an applied voltage (a voltage applied between the first conductive layer and the second conductive layer). Specifically, the substrate is composed of a plurality of elementary elements, the plurality of elementary elements are respectively assigned one through hole of the plurality of through holes, and the maximum width defined on the surface in the first direction and the second direction crossing each other is set to be shorter than the wavelength of the incident light. In this case, three or more elementary elements of the plurality of elementary elements that are continuous in at least either of the first direction and the second direction constitute an elementary unit of modulation control. In addition, one of the first and second conductive layers is connected to a common electrode in the three or more elementary elements constituting the elementary unit. Further, the common electrode includes the second electrode provided on the back surface of the substrate.

[0072] (14) As one embodiment of the present disclosure, it is preferable that the substrate mainly include a semiconductor material. In this case, it is possible to easily use a semiconductor etching process or MACE for the formation of the through holes. Thus, it is possible to easily reduce the arrangement period of the through holes.

[0073] (15) As one embodiment of the present disclosure, the semiconductor material can include at least one of Si, Ge, GaAs, InP, and GaN. In this case, it is possible to use a publicly known etching process for the formation of the through holes, and the formation of the through holes becomes easy.

[0074] (16) As one embodiment of the present disclosure, the first conductive layer can be a metal layer. In this case, light can be sufficiently reflected at the interface between the first conductive layer and the dielectric layer.

[0075] (17) As one embodiment of the present disclosure, the first conductive layer can include Pt. In this case, the first conductive layer can be easily formed in a through-hole having a small inner diameter and a long through direction (i.e., a large aspect ratio) by using, for example, an atomic layer deposition method (ALD).

[0076] (18) As one embodiment of the present disclosure, the dielectric layer can include at least one of aluminum oxide, hafnium oxide, silicon oxide, and silicon nitride. In this case, the dielectric layer having light transmittance can be appropriately implemented.

[0077] (19) As one embodiment of the present disclosure, the second conductive layer can include at least one of ITO, a zinc oxide-based conductive body, titanium nitride, and cadmium oxide. In this case, the second conductive layer having light transmittance can be appropriately implemented.

[0078] (20) The light emitting device of the present disclosure, as one embodiment thereof, can include a spatial light modulator having the above structure, and a surface light source optically coupled to a surface or a back surface of the spatial light modulator. According to this light emitting device, the number of effective pixels can be increased due to the spatial light modulator described above, and thus a high-quality dynamic optical image can be obtained.

[0079] (21) As one embodiment of the present disclosure, it is preferable that the surface light source include a photonic crystal surface-emitting laser element. According to such a structure, for example, the surface light source can be easily implemented.

[0080] (22) As one embodiment of the present disclosure, it is preferable that the surface light source include a surface-emitting laser element having an active layer and a phase modulation layer, the phase modulation layer including a base layer and a plurality of difference refractive index regions having a refractive index different from that of the base layer and distributed in a two-dimensional manner in a plane perpendicular to a thickness direction of the phase modulation layer. In such a structure, the center of gravity of each of the plurality of difference refractive index regions is preferably: (1) disposed in a state deviated from a corresponding lattice point of a virtual square lattice provided on a surface of the phase modulation layer, and a rotation angle centered on the corresponding lattice point defined by an angle formed by a line segment connecting the center of gravity and the corresponding lattice point and the square lattice is individually set; or (2) disposed on a straight line passing through the corresponding lattice point and inclined with respect to the square lattice, and a distance to the corresponding lattice point is individually set. For example, such a structure can also implement the surface light source.

[0081] The above-described "description of embodiments of the present application" section lists each of the modes that can be applied to each of the remaining modes, or all combinations of these remaining modes.

[0082] [Details of Embodiments of the Present Invention]

[0083] Hereinafter, the detailed configuration of the spatial light modulator and the light emitting device according to the present embodiment will be described with reference to the drawings. Note that the present application is not limited to these examples but is intended to include all modifications within the meaning and the scope equivalent to the scope of claims. In addition, the same reference numerals are given to the same elements in the description of the drawings, and the repeated description is omitted.

[0084] (First Embodiment)

[0085] Figure 1 is a cutaway perspective view showing the external appearance of a spatial light modulator 1A according to a first embodiment of the present disclosure, and a part of the spatial light modulator 1A is shown enlarged. The spatial light modulator 1A is a spatial light modulator of a surface waveguide type, and includes a substrate 10.

[0086] The substrate 10 is in a flat plate shape having a surface 11 and a back surface 12. The surface 11 and the back surface 12 are each flat and parallel to each other. The thickness of the substrate 10 (the distance between the surface 11 and the back surface 12) is, for example, 0.05 mm or more and 1.0 mm or less. Further, in a case where the thickness of the substrate 10 is, for example, 0.1 mm or less, the strength of the spatial light modulator 1A becomes low (the impact resistance becomes weak). Therefore, for example, the strength of the spatial light modulator 1A can be increased by adhering another support substrate that is optically transmissive to the surface and / or the back surface of the spatial light modulator 1A. In other words, by adhering another support substrate that is optically transmissive to the surface and / or the back surface of the spatial light modulator 1A, the thickness of the substrate 10 can be reduced. The substrate 10 mainly includes a semiconductor, and in one example, is composed only of a semiconductor. The semiconductor constituting the substrate 10 includes, for example, at least one of Si, Ge, GaAs, InP, and GaN. In one example, the substrate 10 is a Si substrate, a Ge substrate, a GaAs substrate, an InP substrate, or a GaN substrate. The substrate 10 can be a single-crystal substrate, or can be a polycrystal substrate. As the planar shape of the substrate 10, various shapes such as a circular shape, a square shape, and a rectangular shape can be adopted. The diameter (or the length of the long side) of the substrate 10 is, for example, 5 mm or more and 450 mm or less.

[0087] The substrate 10 has a plurality of through-holes 13. The plurality of through-holes 13 penetrate between the surface 11 and the back surface 12. In a plane of the substrate 10 perpendicular to the thickness direction (in other words, a plane parallel to the surface 11 and the back surface 12), the plurality of through-holes 13 are arranged in one dimension or two dimensions. One dimension means that a plurality of objects are arranged side by side in a certain direction. Two dimensions mean that a plurality of objects are arranged side by side in a planar manner with a certain regularity (for example, a plurality of objects are arranged side by side in two orthogonal directions, respectively, and the like). In the present embodiment, in at least one of the surface 11 and the back surface 12, the center of gravity of the planar shape of the plurality of through-holes 13 (in the case where the planar shape is a circular shape, the center of the circular shape) is located at a lattice point of a square lattice.

[0088] In addition, on the surface 11 of the substrate 10, wiring electrodes 32 that are respectively assigned to the plurality of through-holes 13 are provided. Further, these wiring electrodes 32 (first electrodes) can also be composed of a plurality of electrodes. Further, on the back surface 12 of the substrate 10, a wiring electrode 31 (second electrode) that covers the regions between the plurality of through-holes 13 as a common electrode is provided.

[0089] Figure 2 (a) to (i) are diagrams showing examples of the shape of each through-hole 13 as viewed in the thickness direction of the substrate 10. As the shape of the through-hole 13, Figure 2 (a) shows a circular shape, Figure 2 (b) shows a square shape, Figure 2 (c) shows an equilateral triangle shape, Figure 2 (d) shows a regular pentagon shape, Figure 2 (e) shows a regular hexagon shape. These circular shapes or regular polygonal shapes are examples of shapes having rotational symmetry. In addition, Figure 2 (f) shows an elliptical shape, Figure 2 (g) shows a rectangular shape, Figure 2 (h) shows an isosceles triangle shape, Figure 2 (i) shows a trapezoidal shape. These are examples of shapes having mirror symmetry (axial symmetry).

[0090] The shape of the plurality of through-holes 13 as viewed in the thickness direction of the substrate 10 (for example, the shape defined on the surface 11 of the substrate 10) can be the same for all, or can include shapes different from each other. However, the same shape does not necessarily mean the same in a strict sense, and manufacturing errors can be allowed. The inner diameter of each through-hole 13 is, for example, 0.1 μm or more and 10 μm or less. Further, in the following description, the aspect ratio of the through-hole 13 means the ratio (Z2 / Z1) between the inner diameter Z1 of the through-hole 13 and the length Z2 of the through-hole 13 in the direction of penetration.

[0091] Figure 3 is the shape of the through-hole 13 as viewed in the thickness direction of the substrate 10, Figure 1The cross-sectional view along line III-III shown illustrates the longitudinal section of the spatial light modulator 1A. (As shown...) Figure 3 As shown, each through-hole 13 extends straight in the thickness direction of the substrate 10 (in other words, in the direction perpendicular to the surface 11 and the back surface 12). Additionally, as... Figure 3 As shown, the spatial light modulator 1A also includes multiple stacked structures 20. The multiple stacked structures 20 respectively cover the inner wall 13a of each of the multiple through holes 13.

[0092] Figure 4 yes Figure 3 A partially enlarged view. The stacked structure 20 includes: a conductive layer 21 (first conductive layer), a dielectric layer 22, and a conductive layer 23 (second conductive layer). The conductive layer 21 is disposed on the inner wall 13a of the through hole 13. Figure 3 and Figure 4 The conductive layer 21 shown extends from the surface 11 to the back surface 12 on the inner wall 13a of the through-hole 13, but is not limited to this arrangement; it can also be disposed, for example, from the back surface 12 to the through-hole 13 (i.e., not reaching the surface 11). The conductive layer 21 is, for example, a metal layer. In this case, the conductive layer 21 includes, for example, Pt. In one example, the conductive layer 21 is a Pt layer. Furthermore, the conductive layer 21 may also include a metal other than Pt, or may be composed of a metal other than Pt. The thickness t1 of the conductive layer 21 is, for example, 10 nm or more and 1000 nm or less. The surface 21a of the conductive layer 21 is a smooth surface with few irregularities.

[0093] A dielectric layer 22 is disposed on the conductive layer 21, thereby insulating the conductive layer 21 from the conductive layer 23. In this embodiment, the dielectric layer 22 includes a first layer 221 disposed on the conductive layer 21 and a second layer 222 disposed on the first layer 221. Figure 3 and Figure 4The dielectric layer 22 is shown as being provided on the inner wall 13a of the through-hole 13 from the surface 11 to the back surface 12, but is not limited to this manner, and can be provided only on a part of the inner wall 13a (for example, from one of the surface 11 and the back surface 12 to the middle of the through-hole 13) if the conductive layer 21 and the conductive layer 23 are insulated from each other. The dielectric layer 22 and the first layer 221 and the second layer 222 mainly include an inorganic dielectric having light transmittance, and in one example, are composed only of an inorganic dielectric. For example, the first layer 221 and the second layer 222 of the dielectric layer 22 include at least one of aluminum oxide (Al203), hafnium oxide (Hf02), silicon oxide (Si02), and silicon nitride (SiN), and can be a layer in which at least two of them are mixed. In one example, the first layer 221 and the second layer 222 are Al203 layers, Hf02 layers, Si02 layers, or SiN layers. Furthermore, the constituent materials of the first layer 221 and the second layer 222 can be the same as each other or different from each other. In the description of the present embodiment, having light transmittance means that the light absorption coefficient of the wavelength of light (for example, included in the visible light region or the near infrared region) incident on the spatial light modulator 1A is 0.1 cm -1 The following performance. At this time, even if a layer having a thickness of 1 mm is transmitted, the amount of reduction in light intensity is 10% or less. Furthermore, if having light transmittance, at least one of the first layer 221 and the second layer 222 can include or be composed of another dielectric other than Al203, Hf02, Si02, and SiN. The thickness t2 of the dielectric layer 22 is, for example, 1 nm or more and 20 nm or less. The surface of the dielectric layer 22 that contacts the conductive layer 21 is a smooth surface with few irregularities. Furthermore, in a case where the conductive layer 21 can be sufficiently insulated from the conductive layer 23 by only one of the first layer 221 and the second layer 222, the other of the first layer 221 and the second layer 222 can not be provided.

[0094] The conductive layer 23 is provided on the dielectric layer 22. In other words, the conductive layer 23 is provided on the conductive layer 21 with the dielectric layer 22 interposed therebetween. Figure 3 and Figure 4The conductive layer 23 is provided on the inner wall 13a of the through-hole 13 from the surface 11 to the back surface 12, but is not limited to this, and may, for example, be provided from the surface 11 to the middle of the through-hole 13 (i.e., not reach the back surface 12). The conductive layer 23 mainly includes a light-transmissive conductor, and for example, is composed of only a light-transmissive conductor. In one example, the conductive layer 23 includes at least one of an indium tin oxide (ITO) and a zinc oxide-based conductor (e.g., gallium-doped zinc oxide (GZO), aluminum-doped zinc oxide (AZO), or the like), and in one example, the conductive layer 23 is an ITO layer or an AZO layer. Further, the conductive layer 23 can include and can be composed of a light-transmissive conductor other than ITO and AZO. The thickness t3 of the conductive layer 23 is, for example, 1 nm or more and 20 nm or less.

[0095] The conductive layer 24 is provided on the entire surface of the back surface 12. The conductive layer 24 is a layer formed at the same time as the conductive layer 21, and the constituent material is the same as that of the conductive layer 21. In one example, the conductive layer 24 is in contact with the back surface 12. The conductive layer 21 in each of the through-holes 13 is connected to the conductive layer 24. The wiring electrode 31 (second electrode) is provided on the conductive layer 24. The wiring electrode 31 is in contact with the conductive layer 24, and is electrically connected to the conductive layer 21 in each of the through-holes 13 via the conductive layer 24. That is, the wiring electrode 31 is commonly provided for a plurality of through-holes 13. The wiring electrode 31 is, for example, a metal film such as an Au film. Further, the material of the metal film is not limited to Au, and for example, can be a material such as Cr / Au, Ti / Au, Ti / Pt / Au, or the like in order to improve adhesion. Figure 3 and Figure 4 The wiring electrode 31 is provided on the entire surface of the conductive layer 24, and covers the entire region between a plurality of through-holes 13 on the back surface 12. Further, in the region of the back surface 12 in which the through-hole 13 is not formed, the conductive layer 24 and the wiring electrode 31 can be removed. Thus, peeling of the metal when the device is cut out from the wafer can be eliminated, and the attachment of a metal impurity that is difficult to remove can be suppressed.

[0096] The dielectric layer 25 is provided on the entire surface of the surface 11. The dielectric layer 25 is a layer formed at the same time as the first layer 221 or the second layer 222 of the dielectric layer 22 (in the example of the second layer 222), and the constituent material is the same as that of the simultaneously formed first layer 221 or second layer 222. In one example, the dielectric layer 25 is in contact with the surface 11. The first layer 221 or the second layer 222 in each of the through-holes 13 is connected to the dielectric layer 25. Figure 3 and Figure 4 ​

[0097] The conductive layer 26 is provided on the dielectric layer 25. The conductive layer 26 is a layer formed at the same time as the conductive layer 23, and is made of the same material as the conductive layer 23. In one example, the conductive layer 26 is in contact with the dielectric layer 25. Further, a wiring electrode 32 (first electrode) is provided on the conductive layer 26. The wiring electrode 32 is in contact with the conductive layer 26, and is electrically connected to the conductive layer 23 in each through-hole 13 via the conductive layer 26. The conductive layer 26 and the wiring electrode 32 are provided in a separate region for each one or more through-holes 13 (in the example of FIG. 1, for each through-hole 13), and are electrically separated (insulated) for each region (i.e., for each one or more through-holes 13). Figure 3 and Figure 4 The planar shape of the conductive layer 26 and the wiring electrode 32 is a square in the example shown in FIG. 1, but the planar shape of the conductive layer 26 and the wiring electrode 32 is not limited to this, and can be another shape such as a circle, for example. The wiring electrode 32 can also have a layered structure including a first film (e.g., a Cr film or a Ti film) in contact with the conductive layer 26, and a second film (e.g., an Au film) provided on the first film. Further, the wiring electrode 32 can have a layered structure of three or more layers such as Ti / Pt / Au, for example. Figure 1

[0098] The operation of the spatial light modulator 1A described above will be described. As shown in FIG. 2, when light L is incident from the back surface 12 side of the substrate 10, the light L passes through the plurality of through-holes 13. The light L incident at this time is preferably spatially coherent light in which the phase is uniform in space. The light L incident in each through-hole 13 travels while being reflected at the interface between the conductive layer 21 and the dielectric layer 22 of each layered structure 20, and passes through each through-hole 13. At this time, if a voltage is applied between the conductive layer 21 and the conductive layer 23 in a certain through-hole 13, the following three phenomena occur in the layered structure 20. Figure 5 (1) Change in the refractive index of the conductive layer 23 corresponding to the density of the carriers accumulated in the conductive layer 23

[0099]

[0100] ​​Since the conductive layer 21 and the conductive layer 23 are provided in a state of sandwiching the dielectric layer 22, they constitute a capacitor. Therefore, when a voltage is applied between the conductive layer 21 and the conductive layer 23, one of an electron and a hole is accumulated in the vicinity of the interface of the conductive layer 21 with the dielectric layer 22, and the other of the electron and the hole is accumulated in the vicinity of the interface of the conductive layer 23 with the dielectric layer 22. In the case where the conductive layer 23 mainly includes an inorganic conductor such as ITO or AZO, the accumulation of the carrier causes partial metallization in the vicinity of the interface of the conductive layer 23, and the refractive index of the portion changes. The amount of change in the refractive index becomes larger as the carrier accumulation is more (i.e., the applied voltage is larger). The optical path of the light L that transmits through the portion changes accordingly. The change in the refractive index accompanying the carrier accumulation can be estimated, for example, using the Drude model or the like. In the Drude model, the real part of the dielectric constant in the vicinity of the resonance wavelength tends to 0, and is a region where the change in the refractive index is large, which is called an ENZ (Epsilon Near Zero) region. Therefore, by setting the wavelength of light to the ENZ region, a large amount of phase modulation can be achieved.

[0101] (2) Change in refractive index of dielectric layer 22 due to electric field between conductive layer 21 and conductive layer 23

[0102] Since the dielectric layer 22 is sandwiched between the conductive layer 21 and the conductive layer 23, when a voltage is applied between the conductive layer 21 and the conductive layer 23, an electric field through the dielectric layer 22 is generated. Due to the electro-optic effect caused by this electric field, the refractive index of the dielectric layer 22 changes. The amount of change in the refractive index becomes larger as the electric field is stronger (i.e., the applied voltage is larger). The optical path of the light L that transmits through the dielectric layer 22 changes accordingly.

[0103] (3) Change in phase shift amount before and after reflection at the interface of conductive layer 21 and dielectric layer 22

[0104] In the layered structure 20, the light L that has passed through the conductive layer 23 and the dielectric layer 22 is reflected at the conductive layer 21, passes through the dielectric layer 22 and the conductive layer 23 again, and is finally output. In the case where the thickness of the dielectric layer 22 is sufficiently small compared with the wavelength of the light L, when a voltage is applied between the conductive layer 21 and the conductive layer 23, induced current electromagnetic fields that are called gap surface plasmon modes are generated in the conductive layer 21 and the conductive layer 23, respectively, in opposite directions. As a result, a strong magnetic resonance (plasmon resonance) is generated in the dielectric layer 22. Due to this magnetic resonance, the amount of phase shift before and after reflection at the interface between the conductive layer 21 and the dielectric layer 22 changes. The amount of phase change at this time depends on the magnitude of the voltage applied between the conductive layer 21 and the conductive layer 23. In addition, in the case where the layered structure 20 totally reflects, there is also a phase shift called the Goos-Haenchen shift. Therefore, by changing the applied voltage to change the refractive index, it is also possible to control the amount of phase shift.

[0105] Due to the above-described phenomena (1) to (3), the phase of the light L that exits from each through-hole 13 changes depending on the magnitude of the voltage between the conductive layer 21 and the conductive layer 23. Also, the conductive layer 23 of the present embodiment is electrically separated for each group of one or more through-holes 13. As a result, it is possible to individually set the magnitude of the voltage between the conductive layer 21 and the conductive layer 23 for each one or more through-holes 13. Further, the voltage between the conductive layer 21 and the conductive layer 23 is applied from the outside of the spatial light modulator 1A through the wiring electrodes 31 on the back surface 12 and the wiring electrodes 32 on the surface 11. Through the above effects, according to this spatial light modulator 1A, it is possible to dynamically control the phase distribution of the light L in space.

[0106] Figure 6 is a diagram conceptually showing the state of the light L in the case where a gradient is given to the magnitude of the voltage between the conductive layer 21 and the conductive layer 23 for a plurality of through-holes 13 arranged in a certain direction. Figure 6 The length of the arrow of the light L shown indicates the amount of phase change. In the case where a gradient is given to the magnitude of the voltage, as shown in Figure 6 the phase of the light L that exits from each through-hole 13 also has a certain gradient. Also, the exit light L from the spatial light modulator 1A that is a synthesis of these lights L out exits in the direction of the normal line of this gradient. Further, in the present embodiment, the magnitude of the voltage between the conductive layer 21 and the conductive layer 23 is calculated according to a desired optical image, and is arbitrarily determined for each through-hole 13.

[0107] Here, a method of manufacturing the spatial light modulator 1A of the present embodiment will be described. Figure 7 (a) to (c) of FIG. 12. Figure 10(c) is a diagram showing one example of a method of manufacturing the spatial light modulator 1A. First, as shown in Figure 7 (a), a substrate 10 having flat and parallel surfaces 11 and a back surface 12 is prepared. Next, as shown in Figure 7 (b), a resist is applied to the back surface 12 (or the surfaces 11 as well), and the resist is subjected to exposure (or electron beam irradiation) and development, thereby forming a resist mask Ml. The resist mask Ml has a plurality of openings MA corresponding to a plurality of through-holes 13 (refer to Figure 1 ).

[0108] Next, as shown in Figure 7 (c), the substrate 10 is etched through the openings of the resist mask Ml. The etching is, for example, dry etching, and in one example, Inductively Coupled Plasma (ICP) etching by a Bosch process. After that, as shown in Figure 7 (d), the resist mask Ml is removed by organic cleaning. Furthermore, in a case where the etching selectivity of the resist mask Ml to the substrate 10 is insufficient when the substrate 10 is etched, a silicon compound film such as SiN or SiO2 is formed on the back surface 12 (or the surfaces 11) before the resist is applied. The openings MA can be transferred to the silicon compound film after the resist mask Ml is formed on the silicon compound. Also, the substrate 10 can be etched with the silicon compound film as an etching mask. Furthermore, the etching mask is not limited to the silicon compound film, and other inorganic dielectrics such as Al2O3 or HfO2 can be used as well.

[0109] Next, as shown in Figure 8 (a), the conductive layers 21 and 24 are formed. In this process, an Atomic Layer Deposition (ALD) method is used. By the ALD, the material of the conductive layers 21 and 24 can be deposited on the inner walls 13a of the respective through-holes 13 and on the back surface 12 of the substrate 10 isotropically, thinly, and uniformly. Furthermore, in general, the ALD is suitable for film formation inside a high aspect ratio hole, but the conductive layers 21 and 24 can be formed by other methods such as an electroplating technique, evaporation, sputtering, or the like, not limited to the ALD. Next, as shown in Figure 8 (b), a first layer 221 of a dielectric layer 22 is formed. In this process, the ALD is used as with the conductive layers 21 and 24, and the material of the first layer 221 is deposited on the inner walls 13a of the respective through-holes 13 thinly and uniformly. At this time, a dielectric layer 27 composed of the same material as the first layer 221 is formed on the back surface 12 of the substrate 10. In this process as well, the ALD is not limited, and the first layer 221 can be formed by other methods such as sputtering or the like.

[0110] Next, as shown in Figure 8 (c), the conductive layer 24 below the dielectric layer 27 is exposed by removing the dielectric layer 27. In this process, the dielectric layer 27 can be removed, for example, by wet etching using a hydrofluoric acid-based solvent, or dry etching using a hydrofluoric acid-based gas. Next, as shown in Figure 8 (d), the wiring electrode 31 is formed on the exposed conductive layer 24. In this process, the wiring electrode 31 is formed, for example, using plating technology or evaporation.

[0111] Next, as shown in Figure 9 (a), the substrate 10 is turned over so that the surface 11 faces upward. Then, the second layer 222 of the dielectric layer 22 and the dielectric layer 25 are formed. In this process, the material of the second layer 222 and the dielectric layer 25 is deposited thinly and uniformly on the inner wall 13a of each through-hole 13 and the surface 11 of the substrate 10 using ALD, as with the first layer 221. In this process, ALD is not limited, and other methods such as sputtering can also be used to form the second layer 222 and the dielectric layer 25.

[0112] Next, as shown in Figure 9 (b), the conductive layer 23 and the conductive layer 26 are formed. In this process, the material of the conductive layer 23 and the conductive layer 26 is deposited thinly and uniformly on the inner wall 13a of each through-hole 13 and the surface 11 of the substrate 10 using ALD, as with the conductive layers 21 and 24. In this process, ALD is not limited, and other methods such as sputtering can also be used to form the conductive layer 23 and the conductive layer 26.

[0113] Next, as shown in Figure 9 (c), after the resist is applied to the conductive layer 26, the resist is exposed (or electron beam irradiation) and developed, thereby forming a resist mask M2. The resist mask M2 has a lattice-shaped opening MB that surrounds each of the plurality of through-holes 13 or one or more through-holes 13. Then, as shown in Figure 10 (a), the conductive layer 26 is etched through the opening MB of the resist mask M2. In this process, the conductive layer 26 is etched, for example, by wet etching using a hydrofluoric acid-based solvent, or dry etching using a hydrofluoric acid-based gas. Through this process, the conductive layers 23 and 26 are electrically separated for each group of one or more through-holes 13. After that, as shown in Figure 10 (b), the resist mask M2 is removed by organic cleaning. Next, as shown in Figure 10 (c), the wiring electrode 32 is formed on the conductive layer 26. In this process, the wiring electrode 32 is formed, for example, using plating technology. Through the above processes, the spatial light modulator 1A of the present embodiment can be manufactured.

[0114] Figure 11 Figures (a) to (c) illustrate alternative methods (MACE) for forming a plurality of through holes 13 on the substrate 10. First, as... Figure 11 As shown in (a), a plurality of catalyst metal films 41 corresponding to a plurality of through holes 13 are formed on the surface 11 (or the back surface 12). The catalyst metal films 41 include, for example, a Ti layer in contact with the substrate 10 and an Au layer formed on the Ti layer. Alternatively, other metal films (e.g., noble metal films such as Ag, Pt, Pd, or Cu) may be used as the catalyst metal films 41. Then, the substrate 10 is immersed in an etching solution. As the etching solution, a mixture of hydrofluoric acid and an aqueous solution of hydrogen peroxide, for example, can be used. At this time, as... Figure 11 As shown in (b), at the contact area between the catalyst metal film 41 and the substrate 10, the reaction is locally promoted, and the substrate 10 under the catalyst metal film 41 is selectively etched. The etching is advanced as the catalyst metal film 41 descends. As a result, a plurality of recesses 42 with high aspect ratios are formed on the substrate 10. By advancing this etching (through the plurality of recesses 42 through the substrate 10), a plurality of through holes 13 with high aspect ratios can be formed. Alternatively, it can then be done as follows... Figure 11 As shown in (c), the recess 42 is made to penetrate the substrate 10 and the catalyst metal film 41 is removed by etching or grinding (or both) on the side opposite to where the catalyst metal film 41 is formed. In this case, it is also possible to form a plurality of through holes 13 with a high aspect ratio on the substrate 10. Furthermore, by improving the parallelism between the surface 11 and the back surface 12 during etching or grinding, the lengths of the plurality of through holes 13 in the penetration direction can be unified, suppressing deviations in the amount of phase change. Subsequent processes and Figure 8 (a)~ Figure 10 The process shown in (c) is the same.

[0115] The effects obtained by the spatial light modulator 1A of this embodiment, as described above, will be explained. As described above, the spatial light modulator 1A of this embodiment can dynamically control the phase distribution of light in space. Furthermore, since the through-holes 13 can be formed, for example, by a semiconductor etching process or a method such as MACE, the arrangement period of the through-holes 13 can easily be made smaller than the arrangement period of the pixels in a liquid crystal spatial light modulator. Therefore, the spatial light modulator 1A can reduce the arrangement period of the through-holes 13, i.e., the pixels, compared to the prior art. As a result, by combining the spatial light modulator 1A with a surface light source such as a photonic crystal laser element, the effective pixel count can be increased and a high-quality optical image can be obtained.

[0116] Further, compared with the structure described in the above Non-Patent Literature 1, the spatial light modulator 1A of the present embodiment has the following advantages. That is, in the structure described in the above Non-Patent Literature 1, in order to pass light through the recess formed in the surface of the substrate, it is necessary to pass light through the portion of the substrate present under the bottom surface of the recess. Therefore, it is limited to light in a wavelength band that is difficult to be absorbed by the substrate. Further, in the above Non-Patent Literature 1, MACE is used as the method of forming the recess, but if MACE is used in the case of forming a recess having a bottom, the catalyst metal film remains at the bottom of the recess, and light is scattered due to the catalyst metal film. In view of these problems, in the spatial light modulator 1A of the present embodiment, since light L passes within the through-hole 13 between the surface 11 and the back surface 12 of the substrate 10, light L does not need to pass within the substrate 10. Therefore, according to the present embodiment, compared with the structure described in the above Non-Patent Literature 1, it is possible to expand the available wavelength band. Further, even in the case where MACE is used for the formation of the through-hole 13, it is possible to easily remove the catalyst metal film 41, and therefore there is no scattering of light due to the catalyst metal film 41. Therefore, according to the spatial light modulator 1A of the present embodiment, compared with the structure described in the above Non-Patent Literature 1, it is possible to obtain an optical image of high quality.

[0117] As in the present embodiment, the shape of each through-hole 13 viewed in the thickness direction of the substrate 10 can also have rotational symmetry or mirror symmetry. In this case, it is possible to suppress the bias of the direction of emission of light from each through-hole 13.

[0118] As in the present embodiment, the shapes of the plurality of through-holes 13 viewed in the thickness direction of the substrate 10 can also be the same as each other. In this case, it is possible to make the conditions (light intensity, etc.) of the emitted light uniform for each through-hole 13, and it is possible to easily form an optical image of high quality.

[0119] As in the present embodiment, the center of gravity of the plurality of through-holes 13 can also be located at the lattice points of a square lattice or a triangular lattice in at least one of the surface 11 and the back surface 12 of the substrate 10. In this case, the plurality of through-holes 13 are regularly arranged (become easy to design an optical image) in a plane perpendicular to the thickness direction of the substrate 10.

[0120] As in the present embodiment, the conductive layer 23 can also be electrically connected to the wiring electrode 32 on the substrate 10 provided for each through-hole 13. For example, by this structure, it is possible to individually apply a voltage to the conductive layer 23 for each through-hole 13. Further, the conductive layer 21 can also be electrically connected to the wiring electrode 31 on the substrate 10 provided in common for the plurality of through-holes 13. For example, by this structure, it is possible to easily set a potential serving as a reference to the conductive layer 21.

[0121] As in this embodiment, the wiring electrode 31 can also cover the region between the plurality of through holes 13 on the back surface 12 of the substrate 10. In this case, since the light L passing through the substrate portion other than the through holes 13 can be suppressed, the outgoing light L out can be constituted only by the light L passing through the through holes 13 and modulated. In addition, by providing such a wiring electrode 31 on the back surface 12 of the surface as the light incident side, the absorption of the light L in the substrate portion other than the through holes 13, and the temperature rise of the substrate 10 can be suppressed.

[0122] As in this embodiment, the substrate 10 can also mainly include a semiconductor. In this case, a semiconductor etching process or MACE can be used for the formation of the through holes 13. Therefore, it becomes easy to form fine through holes 13 with a high aspect ratio, and it becomes easy to shorten the arrangement period of the through holes 13.

[0123] As in this embodiment, the semiconductor of the substrate 10 can include at least one of Si, Ge, GaAs, InP, and GaN. In this case, a publicly known etching process can be used for the formation of the through holes 13, and the formation of the through holes 13 becomes easy.

[0124] As in this embodiment, the conductive layer 21 can also be a metal layer. In this case, the light L can be sufficiently reflected at the interface of the conductive layer 21 and the dielectric layer 22.

[0125] As in this embodiment, the conductive layer 21 can also include Pt. In this case, the formation of the conductive layer 21 in the through holes 13 with a small inner diameter and a long through direction (i.e., a large aspect ratio) becomes easy, for example, by using ALD.

[0126] As in this embodiment, the dielectric layer 22 can also include at least one of Al2O3, HfO2, SiO2, and SiN. In this case, the formation of the dielectric layer 22 with light transmittance can be appropriately achieved.

[0127] As in this embodiment, the conductive layer 23 can also include at least one of ITO, a zinc oxide-based conductor (GZO, AZO, or the like), titanium nitride, and cadmium oxide. In this case, the formation of the conductive layer 23 with light transmittance can be appropriately achieved.

[0128] (First Modified Example)

[0129] Figure 12is a plan view of a spatial light modulator IB as a first modification of the above-described embodiment. In this spatial light modulator IB, the center of gravity of the planar shape (shape defined on the surface 11) of the plurality of through holes 13 is not the lattice point of a square lattice as in the above-described embodiment, but is located at the lattice point of a triangular lattice. In this case as well, the plurality of through holes 13 are regularly arranged in a plane perpendicular to the thickness direction of the substrate 10, and thus, the design of the optical image can be made easy. Furthermore, as the arrangement of the plurality of through holes 13, it is not limited to the above-described embodiment and the present modification, and various other arrangements can be applied.

[0130] (Second Modification)

[0131] Figures 13-15 are plan views of spatial light modulators 1C to IE as a second modification of the above-described embodiment. In Figure 13 In the spatial light modulator IC illustrated in FIG. 10, the substrate 10 has a plurality of through holes 13 extending linearly in a certain direction Al. These through holes 13 are arranged at a certain interval along a direction A2 intersecting (for example, orthogonal to) the direction Al. The wiring electrode 32 extends in a rectangular frame shape so as to surround the periphery of each through hole 13. In addition, in the spatial light modulator ID illustrated in FIG. 11, the substrate 10 has a plurality of (three in the figure) through holes 13 extending in a circular arc shape around a certain center point C. Also, these through holes 13 extend over an angle range smaller than 360° in polar coordinates with the center point C (origin) as the center, and are arranged at equal intervals in the radial direction. The wiring electrode 32 extends along the edges on both sides of each through hole 13. In addition, in the spatial light modulator IE illustrated in FIG. 12, the substrate 10 also has a plurality of through holes 13 extending in a circular arc shape around a certain center point C. However, in this example, on a circle around the center point C, two or more through holes 13 are arranged at intervals in the circumferential direction, and a plurality of such circles are arranged at equal intervals in a concentric circular shape. Figure 14 Figure 15 In these spatial light modulators 1C to IE, the shape of each through hole 13 as viewed from the thickness direction of the substrate 10 extends in a linear shape, and the plurality of through holes 13 are arranged in a direction intersecting the extending direction of each through hole 13. In the case where the through hole 13 has such a shape, the same effect as in the above-described embodiment can also be achieved. In addition, in the case where the through hole 13 extends like this, etching becomes easy, and at the same time, it is possible to improve the aperture ratio of the phase modulation portion, and more efficient and higher-precision phase control is possible. Furthermore, the light inside the hole is weak in beam confinement in the extending direction, and it is possible to suppress propagation loss.

[0132] (Third Modification)

[0133] (Third Modification)

[0134] ​Figure 16 This is a top view illustrating a third variation of the above-described embodiment of the spatial light modulator 1F. In the spatial light modulator 1F, the substrate 10 has... Figure 13 Multiple through holes 13 of the shape shown. Furthermore, multiple (three in the example) wiring electrodes 32 are provided for each through hole 13. Figure 1 , Figure 12 , Figure 13 In the example shown, one wiring electrode 32 is provided for each through-hole 13, but multiple wiring electrodes 32 can also be provided for each through-hole 13, as in this modified example. In this case, a voltage can be applied to the conductive layer 23 individually for each through-hole 13. In addition, since it is sufficient to connect wiring to any one of the multiple wiring electrodes 32, the degree of freedom in wiring is increased.

[0135] (Fourth variation)

[0136] Figure 17 This is a cross-sectional view illustrating the structure of the spatial light modulator 1G as a fourth variation of the above embodiment. In addition to the structure of the spatial light modulator 1A of the above embodiment, the spatial light modulator 1G also includes a dielectric region 28. The dielectric region 28 is disposed within each through-hole 13 on each stacked structure 20 and is composed of a light-transmitting dielectric. The constituent material of the dielectric region 28 includes, for example, at least one of Al2O3, HfO2, SiO2, and SiN, or it may be a region composed of at least two of them. In one example, the dielectric region 28 is composed only of Al2O3, HfO2, SiO2, or SiN. Furthermore, the constituent materials of the dielectric region 28 and the dielectric layer 22 may be the same or different from each other. Figure 17 In this example, the dielectric region 28 fills the entire space in the through-hole 13 along its through-direction within the space surrounded by the stacked structure 20. However, it is not limited to this example; the dielectric region 28 may also fill a portion of the space in the through-direction of each through-hole 13. Additionally, as... Figure 17 As shown, the end face of one side of the surface 11 of the dielectric region 28 can also reach the wiring electrode 32, and the dielectric region 28 can further fill the gap between adjacent wiring electrodes 32.

[0137] Figure 18 (a) and (b) are diagrams illustrating the process of forming the dielectric region 28 in the fabrication of the spatial light modulator 1G. Firstly, following the above-described embodiment... Figure 7 (a)~ Figure 10 The process shown in (c) is used to produce... Figure 1 The spatial light modulator 1A is shown. Then, as... Figure 18(a) shown, the material of the dielectric region 28 is deposited from the surface 11 side, for example, by ALD. At this time, the dielectric region 28 is buried in a part or all of the through direction of the through-hole 13. After that, as shown in (b) shown, the dielectric region 28 is thinned by etching the dielectric region 28 from the surface 11 side, and thus the wiring electrode 32 is exposed from the dielectric region 28. Thereby, the spatial light modulator 1G of the present modification example is produced. Further, in the case where the wiring electrode 32 is exposed by locally thinning the dielectric region 28, it is also possible that, first, a resist mask having an opening on the wiring electrode 32 is formed on the dielectric region 28, the dielectric region 28 is etched (the wiring electrode 32 is exposed) via the resist mask, and then the resist mask is removed by organic cleaning. Figure 18 (b) shown, the dielectric region 28 is thinned by etching the dielectric region 28 from the surface 11 side, and thus the wiring electrode 32 is exposed from the dielectric region 28. Thereby, the spatial light modulator 1G of the present modification example is produced. Further, in the case where the wiring electrode 32 is exposed by locally thinning the dielectric region 28, it is also possible that, first, a resist mask having an opening on the wiring electrode 32 is formed on the dielectric region 28, the dielectric region 28 is etched (the wiring electrode 32 is exposed) via the resist mask, and then the resist mask is removed by organic cleaning.

[0138] Like the present modification example, the spatial light modulator 1G can also be provided with the dielectric region 28 having light transmittance provided on each layer stack 20. In this case, since the refractive index of the through-hole 13 is greater than 1, and the optical path of the light L passing through is lengthened, the number of times of reflection at the interface between the conductive layer 21 and the dielectric layer 22 increases. Therefore, it is possible to increase the phase modulation amount of each through-hole 13. Or, it is possible to reduce the thickness of the substrate 10 required to achieve a prescribed phase modulation amount. In addition, in this case, the dielectric region 28 can also be at least a part (a part of the section in the through direction) in the through direction of each through-hole 13 among the space surrounded by the layer stack 20. Thereby, the optical path of the light L within the through-hole 13 is further lengthened, and the number of times of reflection at the interface between the conductive layer 21 and the dielectric layer 22 further increases.

[0139] (Fifth Modification Example)

[0140] Figure 19 is a cross-sectional view showing the structure of the spatial light modulator 1H as a fifth modification example of the above-described embodiment. The spatial light modulator 1H is provided with a smoothing layer 29 in addition to the structure of the spatial light modulator 1A of the above-described embodiment. The smoothing layer 29 is provided on the inner wall 13a of each through-hole 13, and has a smooth surface 29a. Also, the layer stack 20 is provided on the surface 29a of the smoothing layer 29. In one example, the conductive layer 21 of the layer stack 20 is in close contact with the surface 29a of the smoothing layer 29. The smoothing layer 29 includes at least one of a metal and a dielectric. In one example, the smoothing layer 29 is a metal layer or a dielectric layer. As an example, a dielectric layer such as Al2O3, HfO2, SiO2, SiN, or a metal layer such as Pt can be used as the smoothing layer 29, and these layers can be formed into a smooth film, for example, by ALD.

[0141] According to the present modification example, even in the case where the concavo-convex due to processing exists in the inner wall 13a of the through-hole 13, the surface of the conductive layer 21 is smooth. Therefore, the diffuse reflection of the light L at the interface between the conductive layer 21 and the dielectric layer 22 can be effectively suppressed. In addition, since the smoothing layer 29 includes at least one of a metal and a dielectric, for example, the smooth surface 29a can be realized regardless of the concavo-convex of the inner wall 13a. In addition, in the case where the smoothing layer 29 is composed of a dielectric that is insulating, since the conductive layer 21 and the substrate 10 can be electrically separated from each other, the current leak from the conductive layer 21 to the substrate 10 can be effectively suppressed. Thus, the control of the applied voltage to the conductive layer 21 can be performed with high precision.

[0142] (dynamic modulation of phase)

[0143] Figure 20 (a) to (c) are diagrams for explaining the structure of a basic element and a basic unit used for explaining the dynamic modulation of phase by intensity modulation of an applied voltage in the spatial light modulators 1A to 1H.

[0144] In each of the spatial light modulators 1A to 1H described above, the substrate 10 can be regarded as a collection of a plurality of basic elements 100, and the basic elements 100 are assigned with one through-hole 13. In Figure 20 In (a), one example of one basic element 100 is shown. Each basic element 100 is composed of a part of the substrate 10 including the corresponding through-hole 13, the wiring electrode 32 provided on the surface 11, and the wiring electrode 31 provided on the back surface 12. In Figure 20 In the example shown in (a), the maximum width W of the basic element 100 defined on the surface 11 in each of two directions (for example, two orthogonal directions) crossing each other is set to be shorter than the wavelength of the incident light.

[0145] Each of the spatial light modulators 1A to 1H described above is composed of a basic unit as a unit of modulation control. For example, in Figure 20 In (b), an example of a basic unit 200A composed of three basic elements 100 continuous in one direction is shown. In addition, in Figure 20 In (c), an example of a basic unit 200B composed of nine (3 x 3) basic elements 100 continuous in each of two directions orthogonal to each other is shown.

[0146] In Figure 20(b) In the basic unit 200A shown, for each of the through holes 13 assigned to three basic elements 100, a wiring electrode 32 is provided on the surface 11, and on the other hand, as a common electrode for the three basic elements 100, a wiring electrode 31 is provided on the back surface 12. As is apparent from the basic unit 200A thus configured, when the transmittance (or reflectance) of each basic element 100 is dynamically modulated, an effect (dynamic phase modulation) of equivalently shifting the position of the exit area 300 (the area indicated by the diagonal line in (b)) of the basic unit 200A can be obtained. Further, such phase modulation utilizes the principle of detour phase hologram disclosed in the above Non-Patent Literature 2, and a spatial light modulator composed of a plurality of basic units is disclosed in the above Non-Patent Literature 3, for example. Figure 20

[0147] Further, in the basic unit 200B shown in (c), for each of the through holes 13 assigned to nine basic elements 100, a wiring electrode 32 is provided on the surface 11, and on the other hand, as a common electrode for the nine basic elements 100, a wiring electrode 31 is provided on the back surface 12. In the basic unit 200B, when the transmittance (or reflectance) of each basic element 100 is dynamically modulated, an effect of equivalently shifting the position of the exit area 300 (the area indicated by the diagonal line in (c)) of the basic unit 200A can be obtained. Figure 20 Figure 20

[0148] As described above, in the case where the spatial light modulators 1A to 1H are composed of a plurality of basic units 200A, one-dimensional phase modulation is possible, and in the case where the spatial light modulators 1A to 1H are composed of a plurality of basic units 200B, two-dimensional phase modulation is possible. Further, the spatial light modulators 1A to 1H can be composed of a plurality of basic units of different structures, as a combination of the basic units 200A and 200B.

[0149] (Second Embodiment)

[0150] Figure 21 ​​​(a) is a cross-sectional view showing the structure of a light-emitting device 2 of a second embodiment of the present disclosure. The light-emitting device 2 includes the spatial light modulator 1A of the above-described embodiment and a surface-emitting laser element 50. The surface-emitting laser element 50 is a surface light source of the present embodiment and is a so-called photonic crystal surface-emitting laser (PCSEL). The surface-emitting laser element 50 is optically coupled to the surface 11 or the back surface 12 (the back surface 12 in the illustrated example) of the spatial light modulator 1A. In one example, the surface-emitting laser element 50 is bonded to the back surface 12 of the spatial light modulator 1A via a bonding portion 51. The bonding portion 51 is, for example, a conductive bonding material such as solder. The material of the bonding portion 51 can also be non-conductive.

[0151] Here, an XYZ orthogonal coordinate system is defined with an axis extending through the center of the surface-emitting laser element 50 and in the thickness direction of the surface-emitting laser element 50 as the Z axis. The surface-emitting laser element 50 forms a standing wave in a direction defined on the X-Y plane and outputs laser light L in a direction (Z direction) perpendicular to the main surface 53a of the semiconductor substrate 53. Further, the Z direction coincides with the thickness direction of the substrate 10 of the spatial light modulator 1A (in other words, the through direction of the through hole 13).

[0152] The surface-emitting laser element 50 includes a semiconductor substrate 53 and a semiconductor stack 60 provided on the main surface 53a of the semiconductor substrate 53. The semiconductor stack 60 includes a cladding layer 61 provided on the main surface 53a, an active layer 62 provided on the cladding layer 61, a cladding layer 63 provided on the active layer 62, and a contact layer 64 provided on the cladding layer 63. In addition, the semiconductor stack 60 includes a photonic crystal layer 65A. The semiconductor stack 60 is formed on the main surface 53a of the semiconductor substrate 53. Figure 21 In the example of (a), the photonic crystal layer 65A is provided between the active layer 62 and the cladding layer 63, but the photonic crystal layer 65A can also be provided between the cladding layer 61 and the active layer 62. Laser light is output from the back surface 53b of the semiconductor substrate 53 as light L illustrated. Figure 5 The light L is supplied to the spatial light modulator 1A.

[0153] The energy band gap of the cladding layers 61 and 63 is wider than the energy band gap of the active layer 62. The thickness directions of the semiconductor substrate 53, the cladding layers 61 and 63, the active layer 62, the contact layer 64, and the photonic crystal layer 65A coincide with the Z axis direction.

[0154] The photonic crystal layer (diffraction grating layer) 65A is a layer that forms a resonance mode. Figure 21(b) is a cross-sectional view showing an enlarged view of the photonic crystal layer 65A. The photonic crystal layer 65A is configured to include a base layer 65a and a plurality of difference refractive index regions 65b. The base layer 65a is a semiconductor layer configured of a first refractive index medium. The plurality of difference refractive index regions 65b are configured of a second refractive index medium having a different refractive index from the first refractive index medium, and exist within the base layer 65a. The difference refractive index regions 65b can also be air holes, or can be configured by embedding a compound semiconductor in the air holes. The plurality of difference refractive index regions 65b are arranged two-dimensionally and periodically in a plane perpendicular to the thickness direction of the photonic crystal layer 65A (a plane parallel to the X-Y plane). In a case where an equivalent refractive index is assumed to be n, a wavelength λ0 (= a x n, a is a grating pitch) selected by the photonic crystal layer 65A is included in the range of the light emission wavelength of the active layer 62. The photonic crystal layer 65A is capable of selecting a wavelength λ0 in the light emission wavelength of the active layer 62 and outputting to the outside.

[0155] Figure 22 is a plan view of the photonic crystal layer 65A. In the photonic crystal layer 65A, a virtual square lattice of the X-Y plane is set. As shown in Figure 22 , the intersection of a line x0 to x3 parallel to the Y axis and a line y0 to y2 parallel to the X axis is set as a lattice point O, and a square region centered on the lattice point O is set as a unit structure region R(0, 0) to R(3, 2). Thus, one side of each unit structure region R(x, y) of the square lattice is parallel to the X axis, and the other side is parallel to the Y axis. At this time, the center of gravity G of each difference refractive index region 65b coincides with each lattice point O of the square lattice (i.e., the center of the unit structure region R(x, y)). The planar shape of the difference refractive index region 65b is, for example, a circular shape, and exists within the unit structure region R (first Brillouin zone) surrounded by a line segment passing through the midpoints of adjacent lattice points and orthogonal to the line segment. Furthermore, the planar shape of the plurality of difference refractive index regions 65b is not limited to a circle, and can be, for example, various shapes such as a polygon, a closed curve, a configuration of two or more closed curves, and the like. In addition, the periodic structure of the plurality of difference refractive index regions 65b is not limited to this, and a triangular lattice can be set instead of the square lattice.

[0156] Referring again to Figure 21The surface-emission laser element 50 also has a metal electrode film 66 provided on the contact layer 64, and a metal electrode film 67 provided on the back surface 53b of the semiconductor substrate 53. The metal electrode film 66 is in ohmic contact with the contact layer 64, and the metal electrode film 67 is in ohmic contact with the semiconductor substrate 53. The metal electrode film 67 has a planar shape in the form of a frame (ring) that surrounds the output region of the laser light, and has an opening 67a. Furthermore, the planar shape of the metal electrode film 67 can also be various shapes such as a rectangular frame, a circular ring, and the like. The metal electrode film 67 can also be joined to the wiring electrode 31 of the spatial light modulator 1A via a conductive joining portion 51, and be at the same potential as the wiring electrode 31 and the like. In particular, in the case where the joining portion 51 is metal, heat generated in the surface-emission laser element 50 can be released through the substrate 10. The portion of the back surface 53b of the semiconductor substrate 53 that is within the opening 67a is covered with an antireflection film 68. As the constituent material of this antireflection film 68, SiN or SiO2, which is a dielectric that is optically transmissive, can be applied. Alternatively, as the constituent material of the antireflection film 68, a transparent conductive film such as ITO, AZO, TiN, or CdO can also be applied. In this case, the current injected from the metal electrode film 67 diffuses over a wide area in a plane that is perpendicular to the thickness direction. Therefore, a thinner semiconductor substrate 53 can be applied. Alternatively, instead of the semiconductor substrate 53, an optically transmissive support substrate can be attached to the semiconductor stack 60. By making the semiconductor substrate 53 thinner or removing the semiconductor substrate 53, light of a wavelength band that is shorter than the band edge wavelength of the semiconductor substrate 53 can be used. The metal electrode film 66 is provided in the central region of the semiconductor stack 60, that is, in the region that coincides with the opening 67a when viewed in the Z direction.

[0157] When a drive current is supplied between the metal electrode film 66 and the metal electrode film 67, recombination of electrons and holes occurs within the active layer 62 (luminescence within the active layer 62). The electrons and holes that contribute to this luminescence, and the generated light, efficiently distribute between the cladding layer 61 and the cladding layer 63. Since the light output from the active layer 62 distributes between the cladding layer 61 and the cladding layer 63, this light, after entering the interior of the photonic crystal layer 65A, forms a resonance mode in the direction along the major surface 53a of the semiconductor substrate 53 in accordance with the lattice structure inside the photonic crystal layer 65A. Furthermore, the light oscillates at a wavelength that corresponds to the arrangement period of the plurality of regions of different refractive index 65b, and laser light is generated. A portion of the laser light that exits from the photonic crystal layer 65A travels in a direction that is perpendicular to the major surface 53a of the semiconductor substrate 53, and is output directly from the back surface 53b toward the spatial light modulator 1A through the opening 67a. In addition, the remaining portion of the laser light that exits from the photonic crystal layer 65A is output from the back surface 53b toward the spatial light modulator 1A through the opening 67a after being reflected from the metal electrode film 66.

[0158] In one example, the semiconductor substrate 53 is a GaAs substrate, the cladding layer 61, the active layer 62, the photonic crystal layer 65A, the cladding layer 63, and the contact layer 64 are composed of GaAs-based semiconductors. In another example, the cladding layer 61 is an AlGaAs layer, the active layer 62 has a multiple quantum well structure (barrier layer: AlGaAs / quantum well layer: InGaAs, the number of well layers is, for example, three), the base layer 65a of the photonic crystal layer 65A is an AlGaAs layer or a GaAs layer, the difference refractive index region 65b is a void, the cladding layer 63 is an AlGaAs layer, and the contact layer 64 is a GaAs layer.

[0159] The cladding layer 61 is given the same conductivity type as the semiconductor substrate 53, and the cladding layer 63 and the contact layer 64 are given the opposite conductivity type to the semiconductor substrate 53. In one example, the semiconductor substrate 53 and the cladding layer 61 are n-type, and the cladding layer 63 and the contact layer 64 are p-type. The photonic crystal layer 65A has the same conductivity type as the semiconductor substrate 53 when disposed between the active layer 62 and the cladding layer 61, and has the opposite conductivity type to the semiconductor substrate 53 when disposed between the active layer 62 and the cladding layer 63. Furthermore, the impurity concentration is, for example, 1 x 1018 / cm3in the semiconductor substrate 53, 1 x 1018 / cm3in the cladding layer 61, 1 x 1018 / cm3in the cladding layer 63, and 1 x 1018 / cm3in the contact layer 64. 16 ~ 1 x 1018 / cm3 21 / cm3 3 In the intrinsic (i-type) where no impurities are intentionally incorporated, the impurity concentration is 1 x 1016 / cm3 16 / cm3 3 The active layer 62 is not limited to an intrinsic (i-type) semiconductor and can be doped. Furthermore, the impurity concentration of the photonic crystal layer 65A can also be intrinsic (i-type) in cases where it is necessary to suppress the effects of loss due to light absorption via impurity energy levels, and so on.

[0160] The light emitting device 2 of the present embodiment described above is provided with the spatial light modulator 1A and the surface light source (the surface-emitting laser element 50) optically coupled to the surface 11 or the back surface 12 of the spatial light modulator 1A. This light emitting device 2, by being provided with the spatial light modulator 1A of the first embodiment, can increase the number of effective pixels and can obtain a high-quality dynamic optical image. In addition, by the surface-emitting laser element 50, it becomes easy to realize a surface light source that provides coherent light to the spatial light modulator 1A. Furthermore, the light emitting device 2 can also be provided with any one of the spatial light modulators 1B to 1H of the above-described various modifications instead of the spatial light modulator 1A. In this case as well, the same operational effects can be achieved.

[0161] Furthermore, in the Figure 21 above, a case where the surface-emitting laser element 50 emits light from the back surface 53b side of the semiconductor substrate 53 is exemplified, and it can also be as in Figure 23As shown, the surface-emission laser element 50 emits light from the main surface 53a side of the semiconductor substrate 53 (i.e., the surface of the semiconductor laminate 60 on the opposite side from the semiconductor substrate 53). In this case, the metal electrode film 66 has a plurality of openings 66a that respectively oppose the plurality of through holes 13. The region of the metal electrode film 66 other than the openings 66a is joined to the wiring electrode 31 of the spatial light modulator 1A in its entirety via the conductive joining portion 51. In addition, the metal electrode film 67 is provided on the entire surface of the back surface 53b. Thus, current can be uniformly injected in the plane perpendicular to the thickness direction of the semiconductor laminate 60. In addition, particularly in the case where the joining portion 51 is a metal such as solder, the spatial light modulator 1A can pass and efficiently release the heat generated in the semiconductor laminate 60. In this case, the metal electrode film 66 is at the same potential as the wiring electrode 31 and the like. The portion of the surface of the semiconductor laminate 60 within the openings 66a of the metal electrode film 66 is covered by the anti-reflection film 68. According to the structure shown in FIG. 6, the spatial light modulator 1A can be supplied with light in a wavelength band shorter than the band edge wavelength of the semiconductor substrate 53 without using a transparent conductive film whose conductivity is not very high. Thus, in the case where the light-emitting device 2 outputs light in a wavelength band shorter than the band edge wavelength of the semiconductor substrate 53, high efficiency of the light-emitting device 2 becomes possible. Figure 23 According to the structure shown in FIG. 6, the spatial light modulator 1A can be supplied with light in a wavelength band shorter than the band edge wavelength of the semiconductor substrate 53 without using a transparent conductive film whose conductivity is not very high. Thus, in the case where the light-emitting device 2 outputs light in a wavelength band shorter than the band edge wavelength of the semiconductor substrate 53, high efficiency of the light-emitting device 2 becomes possible.

[0162] Figure 24 FIG. 7 is a diagram showing an example of the planar shape of the metal electrode film 66 and the joining portion 51. For easy understanding, the region where the joining portion 51 is present is indicated with a cross-hatched line. The planar shape of each opening of the metal electrode film 66 can be the same as the planar shape of the through hole 13, or can be different. As an example, in FIG. 7, the metal electrode film 66 having a plurality of openings 66a whose planar shape is a square is shown. In addition, as shown in FIG. 7, the joining portion 51 can be provided in the entire region between the plurality of openings 66a. In addition, the joining portion 51 can not be provided in the peripheral portion of the metal electrode film 66. Figure 24 Figure 24

[0163] Figure 25 FIG. 8 is a cross-sectional view showing the structure in the case where the semiconductor substrate 53 is removed from the structure shown in FIG. 6. As shown in FIG. 8, by leaving the semiconductor laminate 60 and removing the semiconductor substrate 53 from the surface-emission laser element 50 shown in FIG. 6, a thinned surface-emission laser element 50A can be obtained. In this case, it is possible to avoid absorption of light in a wavelength band shorter than the band edge wavelength of the semiconductor substrate 53 by the semiconductor substrate 53, and it is possible to achieve higher efficiency. Furthermore, in the surface-emission laser element 50A, the metal electrode film 67 is provided on the back surface of the semiconductor laminate 60. Figure 23 Figure 25 Figure 23

[0164] (Sixth Modified Example) ​​​​​

[0165] In the above-described second embodiment, the case where the light emitting device 2 is provided with the PCSEL, i.e., the surface-emission laser element 50, as the surface light source is described. However, the surface light source is not limited to the PCSEL, and various surface-emission laser elements can be employed. For example, a surface-emission laser element that outputs an arbitrary optical image by controlling the phase spectrum and intensity spectrum of light emitted from a plurality of light emitting points arranged in two dimensions is under study. Such a surface-emission laser element is called an S-iPM (Static-integrable Phase Modulating) laser, and can output an optical image of an arbitrary shape in two dimensions including a direction perpendicular to a main surface of a semiconductor substrate and a direction inclined with respect thereto.

[0166] Figure 26 is a plan view of a phase modulation layer 65B provided in the S-iPM laser. The surface-emission laser element 50 of the second embodiment can be provided with the phase modulation layer 65B shown in Figure 22 instead of the photonic crystal layer 65A (see Figure 26 ). In the example of Figure 26 , the intersection of a line x0 to x3 parallel to the Y axis and a line y0 to y2 parallel to the X axis is set as a lattice point O, and a square region (square lattice) centered on the lattice point O is set as a unit structure region R(0, 0) to R(3, 2). Thus, the surface-emission laser element 50 functions as an S-iPM laser. The phase modulation layer 65B is a resonance mode forming layer in the present modification. Further, in the surface-emission laser element 50 of the present modification, the other structures except for the phase modulation layer 65B are the same as those of the second embodiment, and thus detailed description is omitted.

[0167] The phase modulation layer 65B includes a base layer 65a composed of a first refractive index medium, and a difference refractive index region 65b composed of a second refractive index medium different from the first refractive index medium. Here, in the phase modulation layer 65B, a virtual square lattice of the X-Y plane is set. One side of each unit structure region R(x, y) of the square lattice is parallel to the X axis, and the other side is parallel to the Y axis. At this time, the unit structure region R of a square shape centered on the lattice point O can be set in two dimensions over a plurality of columns along the X axis and a plurality of rows along the Y axis. A plurality of difference refractive index regions 65b are provided one by one within each unit structure region R. The planar shape of the difference refractive index region 65b is, for example, a circular shape, but is not limited thereto, and can be, for example, various shapes such as a polygon, a closed curve, composed of two or more closed curves, and the like. In each unit structure region R(x, y), the center of gravity G of the difference refractive index region 65b is disposed separately from the nearest lattice point O.

[0168] As Figure 27As shown, the position within the unit structure region R(x,y) is given by the s-axis (parallel to the X-axis) and t-axis (parallel to the Y-axis) orthogonal at the corresponding grid point O. In the unit structure region R(x,y), the angle between the direction from grid point O towards the centroid G and the s-axis is set as... The x-component represents the position of the x-th grid point O on the X-axis, and the y-component represents the position of the y-th grid point O on the Y-axis. (Regarding the rotation angle...) With a value of 0°, the direction of the vector connecting lattice point O and the centroid G is aligned with the positive direction of the X-axis. Furthermore, the length of the vector connecting lattice point O and the centroid G is set to r(x,y). In one example, r(x,y) is constant and independent of x and y (spread throughout the phase modulation layer 65B).

[0169] like Figure 26 As shown, in the phase modulation layer 65B, the rotation angle of the centroid G of the differential refractive index region 65b about the lattice point O is... Based on the desired optical image, the rotation angle distribution is set independently for each unit structure region R. Each position, determined by the values ​​of components x and y, has specific values, but is not necessarily represented by a specific function. That is, the rotation angle distribution. The phase distribution is determined by extracting the complex amplitude distribution obtained from the inverse Fourier transform of the desired optical image. Furthermore, when obtaining the complex amplitude distribution from the desired optical image, the reproducibility of the beam pattern is improved by applying an iterative algorithm such as the Gerchberg-Saxton (GS) method commonly used in hologram generation calculations.

[0170] Figure 28 This is a diagram illustrating the relationship between the optical image obtained by imaging the output beam pattern of the surface-emitting laser element 50 and the rotation angle distribution φ(x,y) in the phase modulation layer 65B. Furthermore, the center Q of the output beam pattern (wavenumber space) is not limited to being located on an axis perpendicular to the main surface 53a of the semiconductor substrate 53, and can also be positioned on a vertical axis. For illustrative purposes, the center Q is set here to be located on an axis perpendicular to the main surface 53a. Figure 28 The diagram shows the four quadrants with center Q as the origin. Figure 28 The example shows the possibility of obtaining optical images in the first and third quadrants, but it is also possible to obtain optical images in the second and fourth quadrants or all quadrants. In this variation, as shown... Figure 28 As shown, an optical image that is point-symmetric about the origin can be obtained. Figure 28As an example, a case where a letter "A" is obtained in the third quadrant and a pattern obtained by rotating the letter "A" by 180 degrees is obtained in the first quadrant is shown. Further, in a case of a rotationally symmetrical optical image (for example, a cross, a circle, a double circle, or the like), the superposition is observed as one optical image.

[0171] The optical image of the output beam pattern of the surface-emitting laser element 50 includes at least one of a spot, a straight line, a cross, a line pattern, a lattice pattern, a photograph, a fringe pattern, a CG (Computer Graphics), and a letter. Here, in order to obtain a desired optical image, the rotation angle distribution of the difference refractive index region 65b of the phase modulation layer 65B is determined by the following method

[0172] In the present modification example, the rotation angle distribution can be determined by the following method so that a desired optical image is obtained. First, as a first precondition, in an XYZ orthogonal coordinate system defined by a Z axis and an X-Y plane, on the X-Y plane, a virtual square lattice composed of M1 (an integer of 1 or more) x N1 (an integer of 1 or more) unit structure regions R each having a square shape is set, where the Z axis coincides with the normal direction, the X-Y plane coincides with one face of the phase modulation layer 65B including a plurality of difference refractive index regions 65b and has X and Y axes orthogonal to each other.

[0173] As a second precondition, as shown in Figure 29 , a spherical coordinate (r, θ tilt , θ rot ) defined by a radial length r, an inclination angle θ rot from the Z axis, and a rotation angle θ tilt from the X axis determined on the X-Y plane satisfies the following relationships shown by equations (1) to (3). Further, Figure 29 is a graph for explaining a coordinate transformation from the spherical coordinate (r, θ rot , θ tilt ) to the coordinate (ξ, η, ζ) under the XYZ orthogonal coordinate system, and by the coordinate (ξ, η, ζ), a designed optical image on a prescribed plane set as a real space XYZ orthogonal coordinate system is represented. When a beam pattern corresponding to the optical image output from the surface-emitting laser element is set as a collection of bright spots toward directions prescribed by the angles θ tilt and θ rot , the angles θ tilt and θ rot are convertible to a normalized wave number k x, and a normalized wave number defined by the following formula (5) that is a coordinate value on a Ky axis corresponding to the Y axis and orthogonal to the Kx axis, k y The normalized wave number refers to a wave number normalized so that a wave number 2π / a equivalent to a lattice spacing of a virtual square lattice is 1.0. At this time, in a wave number space defined by the Kx axis and the Ky axis, a specific wave number range including a light beam pattern equivalent to an optical image is composed of M2 (an integer of 1 or more) x N2 (an integer of 1 or more) square-shaped image regions FR, respectively. Further, the integer M2 need not necessarily coincide with the integer M1. Similarly, the integer N2 need not necessarily coincide with the integer N1. In addition, the formula (4) and the formula (5) are disclosed, for example, in the above Non-Patent Literature 4.

[0174] ξ = r sin θ tilt cos θ rot …(1)

[0175] η = r sin θ tilt sin θ rot …(2)

[0176] ζ = r cos θ tilt …(3)

[0177]

[0178]

[0179] a: lattice constant of a virtual square lattice

[0180] λ: oscillation wavelength of the surface-emission laser element 50

[0181] As a third precondition, in the wave number space, by the image region FR(k x (0 or more and an integer of M2-1) and the coordinate component k y (0 or more and an integer of N2-1) of the Ky axis direction, the image region FR(k x , k y) The complex amplitude F(x, y) obtained by performing two-dimensional inverse Fourier transform on the unit structure region R(x, y) on the X-Y plane specified by the coordinate component x (an integer of 0 or more and M1-1 or less) in the X-axis direction and the coordinate component y (an integer of 0 or more and N1-1 or less) in the Y-axis direction, respectively, is given by the following equation (6) with j as an imaginary part. In addition, the complex amplitude F(x, y) is specified by the following equation (7) when the amplitude term is set to A(x, y) and the phase term is set to P(x, y). In addition, as the fourth precondition, the unit structure region R(x, y) is specified by s- and t-axes that are parallel to the X- and Y-axes, respectively, and orthogonal to the lattice point O(x, y) at the center of the unit structure region R(x, y).

[0182]

[0183] F(x, y) = A(x, y) x exp[jP(x, y)]... (7)

[0184] Under the above first to fourth preconditions, the phase modulation layer 65B is configured to satisfy the following first and second conditions. That is, the first condition is that, within the unit structure region R(x, y), the center of gravity G is configured in a state of deviating from the lattice point O(x, y). The second condition is that, in a state where the line segment length r2(x, y) from the lattice point O(x, y) to the corresponding center of gravity G is set to a common value for each of the M1 x N1 unit structure regions R, the angle formed by the line segment connecting the lattice point O(x, y) and the corresponding center of gravity G and the s-axis is The corresponding difference refractive index region 65b is configured within the unit structure region R(x, y) in a manner satisfying the following relationship.

[0185]

[0186] C: a proportional constant, for example, 180° / π

[0187] B: an arbitrary constant, for example, 0.

[0188] As a method of obtaining the intensity distribution and the phase distribution from the complex amplitude distribution obtained by inverse Fourier transform, for example, the intensity distribution I(x, y) can be calculated by using the abs function of the numerical analysis software "MATLAB" of MathWorks, Inc., and the phase distribution P(x, y) can be calculated by using the angle function of MATLAB.

[0189] Here, the rotation angle distribution φ(x, y) is explained from the inverse Fourier transform result of the optical image And points to be noted in the case where a usual discrete Fourier transform (or a fast Fourier transform) is used for calculation in determining the configuration of the respective difference refractive index regions 65b. When the optical image before the Fourier transform is divided into four quadrants A1, A2, A3, and A4 as in Figure 30 (a), the resulting beam pattern is as in Figure 30 (b). That is, in the first quadrant of the beam pattern, a pattern in which the pattern of the first quadrant of (a) is overlaid with the pattern of the third quadrant of (a) appears. In the second quadrant of the beam pattern, a pattern in which the pattern of the second quadrant of (a) is overlaid with the pattern of the fourth quadrant of (a) appears. In the third quadrant of the beam pattern, a pattern in which the pattern of the third quadrant of (a) is overlaid with the pattern of the first quadrant of (a) appears. In the fourth quadrant of the beam pattern, a pattern in which the pattern of the fourth quadrant of (a) is overlaid with the pattern of the second quadrant of (a) appears. Figure 30 Figure 30 Figure 30 Figure 30 Figure 30 Figure 30 Figure 30 Figure 30

[0190] Therefore, in the case where a pattern having a value only in the first quadrant is used as the optical image before the inverse Fourier transform (the original optical image), the pattern of the first quadrant of the original optical image appears in the third quadrant of the resulting beam pattern, and a pattern in which the first quadrant of the original optical image is rotated by 180 degrees appears in the first quadrant of the resulting beam pattern.

[0191] As described above, in the surface-emission laser element 50, it is possible to obtain a desired beam pattern by phase-modulating the wave front. The beam pattern is not only a pair of single-peak beams (spots), but also can be a letter shape, a group of points of two or more identical shapes, or a vector beam in which the phase and intensity distributions are not uniform in space, as described above.

[0192] In the present modification example, the laser light output from the active layer 62 is confined between the cladding layer 61 and the cladding layer 63 and enters the inside of the phase modulation layer 65B, forming a prescribed pattern corresponding to the lattice structure inside the phase modulation layer 65B. The laser light scattered within the phase modulation layer 65B and emitted therefrom is output to the outside from the back surface 53b of the semiconductor substrate 53. At this time, the 0th order light is emitted in a direction perpendicular to the main surface 53a. In contrast, the +1st order light and the -1st order light are emitted in an arbitrary direction in two dimensions including the direction perpendicular to the main surface 53a and a direction inclined thereto.

[0193] ​​​​​​​​Furthermore, in the above explanation of this variation, the wavelength λ0 is set to λ0 = a × n (where a is the grid spacing), utilizing the band edge of the square grid, referred to as Γ2 point. On the other hand, the grid spacing a can also be set to λ0 = (2... 1 / 2 )a×n. This corresponds to the edge of the square lattice, called point M. In this case, the phase angle distribution corresponding to the design beam pattern. The additional phase angle distribution The phase is set to an overlapping phase angle distribution. Figure 31 It conceptually illustrates the distribution of rotation angles. An example diagram. (For example...) Figure 31 As shown, in this example, the first phase value and the first phase value Second phase value of different values Arranged in a grid pattern. In one example, the phase value... The phase value is 0 (rad). It is π (rad). That is, the first phase value. Second phase value The change is π. In this case, a designed beam pattern can be extracted in the direction perpendicular to the surface, and a designed beam pattern consisting only of ±1-order lights can be emitted without zero-order light appearing in the direction perpendicular to the surface. Zero-order light is a wavefront without phase modulation, while ±1-order light is a wavefront with phase modulation. Therefore, the spatial phase distribution of light incident on the spatial light modulator 1A can be effectively controlled, for example, by concentrating the light into the through-hole 13 to achieve high efficiency.

[0194] As in this modified example, the surface-emitting laser element 50 may also have a phase modulation layer 65B as a resonant mode forming layer. In this case, a portion of the laser light generated in the phase modulation layer 65B (a portion of the +1st order light and the -1st order light, as well as the 0th order light) diffracts in a direction perpendicular to the main surface 53a of the semiconductor substrate 53, and after being reflected by the metal electrode film 66 (or directly), reaches the back surface 53b of the semiconductor substrate 53, and is emitted from the back surface 53b toward the spatial light modulator 1A. Therefore, the same effect as in the second embodiment can be achieved. In addition, as described above, by controlling the spatial phase of the ±1st order light of the emitted beam of the S-iPM laser (e.g., concentrating the light toward the through-hole 13, etc.), the efficiency can be further improved.

[0195] (Seventh variation)

[0196] The S-iPM laser is not limited to the structure of the above-described sixth modification example. For example, even if the structure of the phase modulation layer of the present modification example, the S-iPM laser can be appropriately implemented. Figure 32 is a plan view of the phase modulation layer 65C provided in the S-iPM laser. Figure 33 is a diagram showing the positional relationship of the difference refractive index regions 65b in the phase modulation layer 65C. The phase modulation layer 65C is the resonant mode forming layer of the present modification example. Further, as shown in Figure 32 is a plan view of the phase modulation layer 65C provided in the S-iPM laser. Figure 32 and Figure 33 In the phase modulation layer 65C, the barycentric point G of each difference refractive index region 65b is disposed on a straight line D. The straight line D is a straight line passing through the corresponding lattice point O of each unit structure region R and inclined with respect to each side of the square lattice. In other words, the straight line D is a straight line inclined with respect to both the X axis (s axis) and the Y axis (t axis). The inclination angle of the straight line D with respect to the s axis parallel to the X axis is θ. The inclination angle θ is constant within the phase modulation layer 65C. The inclination angle θ satisfies 0° < θ < 90°, and in one example, θ = 45°. Alternatively, the inclination angle θ satisfies 180° < θ < 270°, and in one example, θ = 225°. In the case where the inclination angle θ satisfies 0° < θ < 90° or 180° < θ < 270°, the straight line D extends from the first quadrant to the third quadrant of the coordinate plane defined by the X axis and the Y axis. Alternatively, the inclination angle θ satisfies 90° < θ < 180°, and in one example, θ = 135°. Alternatively, the inclination angle θ satisfies 270° < θ < 360°, and in one example, θ = 315°. In the case where the inclination angle θ satisfies 90° < θ < 180° or 270° < θ < 360°, the straight line D extends from the second quadrant to the fourth quadrant of the coordinate plane defined by the X axis and the Y axis. As described above, the inclination angle θ is an angle other than 0°, 90°, 180°, and 270°. By setting such an inclination angle θ, both the light wave traveling in the X axis direction and the light wave traveling in the Y axis direction can be assisted in the light output beam. Here, the distance of the lattice point O from the barycentric point G is denoted by r(x, y). x denotes the position of the x-th lattice point on the X axis, and y denotes the position of the y-th lattice point on the Y axis. In the case where the distance r(x, y) is positive, the barycentric point G is located in the first quadrant (or the second quadrant). In the case where the distance r(x, y) is negative, the barycentric point G is located in the third quadrant (or the fourth quadrant). In the case where the distance r(x, y) is 0, the lattice point O and the barycentric point G coincide with each other.

[0197] Figure 32 The distance r(x,y) between the centroid G of each differential refractive index region 65b and the corresponding lattice point O of each unit structure region R is individually set for each differential refractive index region 65b according to the desired optical image. The distribution of distance r(x,y) has a specific value for each position determined by the values ​​of x and y, but is not limited to being expressed by a specific function. The distribution of distance r(x,y) is determined by extracting the phase distribution from the complex amplitude distribution obtained by performing an inverse Fourier transform on the desired optical image. That is, in Figure 33 As shown, when the phase P(x,y) of the unit structure region R(x,y) is P0, the distance r(x,y) is set to 0; when the phase P(x,y) is π+P0, the distance r(x,y) is set to the maximum value r0; and when the phase P(x,y) is -π+P0, the distance r(x,y) is set to the minimum value -r0. Furthermore, for the intermediate phase P(x,y), the distance r(x,y) is set to r(x,y) = {P(x,y) - P0} × r0 / π. Here, the initial phase P0 can be arbitrarily set. When the grid spacing of the square lattice is set to a, the maximum value r0 of r(x,y) is, for example, within the range of the following equation (8).

[0198]

[0199] As in this modified example, the surface-emitting laser element 50 may also have a phase modulation layer 65C as a resonant mode forming layer. In this case, a portion of the laser light generated in the phase modulation layer 65C (a portion of the +1st order light and the -1st order light, as well as the 0th order light) diffracts in a direction perpendicular to the main surface 53a of the semiconductor substrate 53, and after being reflected by the metal electrode film 66 (or directly), reaches the back surface 53b of the semiconductor substrate 53, and is emitted from the back surface 53b toward the spatial light modulator 1A. Therefore, the same effect as in the second embodiment can be achieved. In addition, by controlling the spatial phase of the ±1st order light of the emitted beam of the S-iPM laser (e.g., concentrating the light toward the through-hole 13, etc.), the efficiency can be further improved.

[0200] The spatial light modulator and light-emitting device disclosed herein are not limited to the embodiments described above, and various other modifications are possible. For example, in the spatial light modulators of the above embodiments and their modifications, one or more wiring electrodes 32 provided for each through-hole 13 are electrically connected to the conductive layer 23, and wiring electrodes 31 commonly provided for multiple through-holes 13 are electrically connected to the conductive layer 21. The spatial light modulator disclosed herein is not limited to this method; for example, it may also be that one or more wiring electrodes 32 provided for each through-hole 13 are electrically connected to the conductive layer 21, and wiring electrodes 31 commonly provided for multiple through-holes 13 are electrically connected to the conductive layer 23.

[0201] In addition, in the spatial light modulator of the above embodiment and each modification, the one or more wiring electrodes 32 provided for each through-hole 13 are provided on the surface 11, and the wiring electrode 31 provided commonly for the plurality of through-holes 13 is provided on the back surface 12. The spatial light modulator of the present disclosure is not limited to this, and for example, the one or more wiring electrodes 32 provided for each through-hole 13 can be provided on the back surface 12, and the wiring electrode 31 provided commonly for the plurality of through-holes 13 can be provided on the surface 11. In this case, the conductive layer 24 connected to the conductive layer 21 is separated for each or the one or more through-holes 13, and the conductive layer 26 connected to the conductive layer 23 is provided commonly for the plurality of through-holes 13. Further, in this case, the wiring electrode 31 can also cover the regions between the plurality of through-holes 13 on the surface 11.

[0202] In addition, in the above embodiment and each modification, the light L is incident on the spatial light modulator from the back surface 12 side and is emitted from the surface 11 side, and the light L can also be incident on the spatial light modulator from the surface 11 side and be emitted from the back surface 12 side.

[0203] Explanation of Reference Signs

[0204] 1A to 1H …… spatial light modulator, 2 …… light emitting device, 10 …… substrate, 11 …… surface, 12 …… back surface, 13 …… through-hole, 13a …… inner wall, 20 …… layered structure, 21, 24 …… conductive layer, 21a …… surface, 22, 25, 27 …… dielectric layer, 23, 26 …… conductive layer, 28 …… dielectric region, 29 …… smoothing layer, 29a …… surface, 31, 32 …… wiring electrode, 41 …… catalyst metal film, 42 …… recess, 50 …… surface-emitting laser element, 51 …… bonding portion, 53 …… semiconductor substrate, 53a …… main surface, 53b …… back surface, 60 …… semiconductor layered, 61 …… cladding layer, 62 …… active layer, 63 …… cladding layer, 64 …… contact layer, 65A …… photonic crystal layer, 65B, 65C …… phase modulation layer, 65a …… base layer, 65b …… difference refractive index region, 66, 67 …… metal electrode film, 67a …… opening, 68 …… anti-reflection film, 100 …… essential element, 200A, 200B …… essential unit, 221 …… first layer, 222 …… second layer, 300 …… emission region, A1, A2 …… direction, C …… center point, D …… straight line, G …… center of gravity, L …… light, L out … … emitted light, M1, M2 …… resist mask, MA, MB …… opening, O …… lattice point, R …… unit structure region, θ …… tilt angle, … … rotation angle.

Claims

1. A spatial light modulator, wherein is a spatial light modulator of a slab waveguide type, has: a substrate having a surface, a back surface opposite to the surface, and a plurality of through holes each of which communicates the surface and the back surface, each of the openings defined on the surface is configured in a one-dimensional or two-dimensional shape, and a plurality of laminated structures each of which covers an inner wall of each of the plurality of through holes, each of the plurality of laminated structures includes: a first conductive layer provided on the inner wall of a corresponding one of the plurality of through holes, a dielectric layer provided on the first conductive layer and having optical transmittance, and a second conductive layer provided on the dielectric layer and having optical transmittance, at least one of the first and second conductive layers is electrically separated for each group constituted by one or more of the plurality of through holes.

2. The spatial light modulator according to claim 1, wherein the opening shape of each of the plurality of through holes defined on the surface has rotational symmetry or mirror symmetry.

3. The spatial light modulator according to claim 1, wherein the opening shape of each of the plurality of through holes defined on the surface is identical to each other.

4. The spatial light modulator according to claim 2, wherein the opening shape of each of the plurality of through holes defined on the surface is identical to each other.

5. The spatial light modulator according to claim 1, wherein on at least one of the surface and the back surface, the opening center of gravity of each of the plurality of through holes is located at a lattice point of a square lattice or a triangular lattice.

6. The spatial light modulator according to claim 2, wherein on at least one of the surface and the back surface, the opening center of gravity of each of the plurality of through holes is located at a lattice point of a square lattice or a triangular lattice.

7. The spatial light modulator according to claim 3, wherein on at least one of the surface and the back surface, the opening center of gravity of each of the plurality of through holes is located at a lattice point of a square lattice or a triangular lattice.

8. The spatial light modulator according to claim 4, wherein on at least one of the surface and the back surface, the opening center of gravity of each of the plurality of through holes is located at a lattice point of a square lattice or a triangular lattice.

9. The spatial light modulator according to claim 1, wherein the opening shape of each of the plurality of through holes defined on the surface is a shape extending in a linear shape.

10. The spatial light modulator according to claim 9, wherein the opening shape of each of the plurality of through holes includes a straight line shape or a circular arc shape.

11. The spatial light modulator according to claim 10, wherein the opening shape of each of the plurality of through holes includes the circular arc shape extending across an angle range smaller than 360° in a polar coordinate with an origin as a center, on the surface, the plurality of through holes are arranged equidistantly in a radial direction.

12. The spatial light modulator according to any one of claims 1 to 11, wherein In each of the plurality of through-holes, there is further provided a dielectric region provided on a corresponding one of the plurality of laminated structures and having light transmissivity.

13. The spatial light modulator according to claim 12, wherein The dielectric region at least fills a prescribed interval defined along a thickness direction from the surface toward the back surface in a space surrounded by the corresponding laminated structure.

14. The spatial light modulator according to any one of claims 1 to 11, wherein In each of the plurality of through-holes, there is further provided a smoothing layer provided on the inner wall and having a smooth surface, In each of the plurality of through-holes, the corresponding one of the plurality of laminated structures is provided on the surface of the smoothing layer.

15. The spatial light modulator according to claim 12, wherein In each of the plurality of through-holes, there is further provided a smoothing layer provided on the inner wall and having a smooth surface, In each of the plurality of through-holes, the corresponding one of the plurality of laminated structures is provided on the surface of the smoothing layer.

16. The spatial light modulator according to claim 13, wherein In each of the plurality of through-holes, there is further provided a smoothing layer provided on the inner wall and having a smooth surface, In each of the plurality of through-holes, the corresponding one of the plurality of laminated structures is provided on the surface of the smoothing layer.

17. The spatial light modulator according to claim 14, wherein The smoothing layer includes at least one of a metal and a dielectric.

18. The spatial light modulator according to claim 15, wherein The smoothing layer includes at least one of a metal and a dielectric.

19. The spatial light modulator according to claim 16, wherein The smoothing layer includes at least one of a metal and a dielectric.

20. The spatial light modulator according to any one of claims 1 to 11, wherein One of the first and second conductive layers is electrically connected to one or more first electrodes provided on the surface of the substrate corresponding to each of the plurality of through-holes.

21. The spatial light modulator according to claim 12, wherein One of the first and second conductive layers is electrically connected to one or more first electrodes provided on the surface of the substrate corresponding to each of the plurality of through-holes.

22. The spatial light modulator according to claim 13, wherein One of the first and second conductive layers is electrically connected to one or more first electrodes provided on the surface of the substrate corresponding to each of the plurality of through-holes.

23. The spatial light modulator according to claim 14, wherein One of the first and second conductive layers is electrically connected to one or more first electrodes provided on the surface of the substrate corresponding to each of the plurality of through-holes.

24. The spatial light modulator according to any one of claims 15 to 19, wherein One of the first and second conductive layers is electrically connected to one or more first electrodes provided on the surface of the substrate corresponding to each of the plurality of through holes.

25. The spatial light modulator of claim 20, wherein The other of the first and second conductive layers is electrically connected to a second electrode provided on the back surface of the substrate in common to the plurality of through holes.

26. The spatial light modulator of any one of claims 21 to 23, wherein The other of the first and second conductive layers is electrically connected to a second electrode provided on the back surface of the substrate in common to the plurality of through holes.

27. The spatial light modulator of claim 24, wherein The other of the first and second conductive layers is electrically connected to a second electrode provided on the back surface of the substrate in common to the plurality of through holes.

28. The spatial light modulator of claim 25, wherein The second electrode covers an area between the plurality of through holes on the surface or the back surface of the substrate.

29. The spatial light modulator of claim 26, wherein The second electrode covers an area between the plurality of through holes on the surface or the back surface of the substrate.

30. The spatial light modulator of claim 27, wherein The second electrode covers an area between the plurality of through holes on the surface or the back surface of the substrate.

31. The spatial light modulator of any one of claims 1 to 11, wherein The substrate is composed of a plurality of elementary elements to which one of the plurality of through holes is respectively assigned and which are respectively defined on a surface of the substrate along first and second directions intersecting each other with a maximum width set to be shorter than a wavelength of incident light, Three or more of the plurality of elementary elements which are continuous in at least either of the first and second directions constitute an elementary unit of modulation control, One of the first and second conductive layers is electrically connected to a common electrode provided on a surface constituting a part of the back surface of the substrate.

32. The spatial light modulator of claim 12, wherein The substrate is composed of a plurality of elementary elements to which one of the plurality of through holes is respectively assigned and which are respectively defined on a surface of the substrate along first and second directions intersecting each other with a maximum width set to be shorter than a wavelength of incident light, Three or more of the plurality of elementary elements which are continuous in at least either of the first and second directions constitute an elementary unit of modulation control, One of the first and second conductive layers is electrically connected to a common electrode provided on a surface constituting a part of the back surface of the substrate.

33. The spatial light modulator of claim 13, wherein The substrate is composed of a plurality of elementary elements each of which is assigned one of the plurality of through-holes and each of which has a maximum width defined on a surface of the substrate in a first direction and a second direction crossing each other set to be shorter than a wavelength of incident light, three or more of the elementary elements which are continuous in at least either of the first direction and the second direction constitute an elementary unit of modulation control, one of the first and second conductive layers is electrically connected to a common electrode provided on a surface of a portion of the back surface of the substrate.

34. The spatial light modulator of claim 14, wherein The substrate is composed of a plurality of elementary elements each of which is assigned one of the plurality of through-holes and each of which has a maximum width defined on a surface of the substrate in a first direction and a second direction crossing each other set to be shorter than a wavelength of incident light, three or more of the elementary elements which are continuous in at least either of the first direction and the second direction constitute an elementary unit of modulation control, one of the first and second conductive layers is electrically connected to a common electrode provided on a surface of a portion of the back surface of the substrate.

35. The spatial light modulator of any one of claims 15 to 19, wherein The substrate is composed of a plurality of elementary elements each of which is assigned one of the plurality of through-holes and each of which has a maximum width defined on a surface of the substrate in a first direction and a second direction crossing each other set to be shorter than a wavelength of incident light, three or more of the elementary elements which are continuous in at least either of the first direction and the second direction constitute an elementary unit of modulation control, one of the first and second conductive layers is electrically connected to a common electrode provided on a surface of a portion of the back surface of the substrate.

36. The spatial light modulator of any one of claims 1 to 11, wherein The substrate mainly includes a semiconductor material.

37. The spatial light modulator of claim 36, wherein The semiconductor material includes at least one of Si, Ge, GaAs, InP, and GaN.

38. The spatial light modulator of any one of claims 1 to 11, wherein The first conductive layer is a metal layer.

39. The spatial light modulator of claim 38, wherein The first conductive layer includes Pt.

40. The spatial light modulator of any one of claims 1 to 11, wherein The dielectric layer includes at least one of aluminum oxide, hafnium oxide, silicon oxide, and silicon nitride.

41. The spatial light modulator of any one of claims 1 to 11, wherein The second conductive layer includes at least one of ITO, a zinc oxide-based conductive body, titanium nitride, and cadmium oxide.

42. A light-emitting device, comprising: provided with: the spatial light modulator according to any one of claims 1 to 41; and a surface light source optically coupled to the surface or the back surface of the spatial light modulator.

43. The light-emitting device according to claim 42, wherein the surface light source includes a photonic crystal surface-emitting laser element.

44. The light-emitting device according to claim 42, wherein the surface light source includes a surface-emitting laser element having an active layer and a phase modulation layer, the phase modulation layer includes a base layer and a plurality of regions of different refractive index having a refractive index different from that of the base layer and distributed in two dimensions in a plane perpendicular to the thickness direction of the phase modulation layer, for each of the plurality of regions of different refractive index: the center of gravity thereof is disposed deviated from a corresponding lattice point of a virtual square lattice set on the surface of the phase modulation layer, and a rotation angle centered on the corresponding lattice point defined by an angle formed by a line segment connecting the center of gravity and the corresponding lattice point and the virtual square lattice is individually set, or the center of gravity thereof is disposed on a straight line passing through a corresponding lattice point of a virtual square lattice set on the surface of the phase modulation layer and inclined with respect to the virtual square lattice, and a distance to the corresponding lattice point is individually set.

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