Photonic crystal surface emitting laser element

Abstract

The utility model provides a photonic crystal surface emitting type laser element. The photonic crystal surface emitting type laser element comprises a photonic crystal surface emitting type laser chip and a metasurface. The photonic crystal surface emitting type laser chip is provided with a light emitting surface and comprises a photonic crystal layer, the photonic crystal layer comprises a plurality of right-angle triangular prism-shaped holes arranged in an array, and inclined planes of the right-angle triangular prism-shaped holes are parallel to one another. And the metasurface monolith is integrated on the light emitting surface of the photonic crystal surface emitting type laser chip. Therefore, the photonic crystal surface emitting type laser element provided by the utility model can achieve a good optical transmission effect through a simple framework.

Description

Technical Field

[0001] The utility model relates to a laser element, in particular to a photonic crystal surface emitting laser (PCSEL) element. Background Art

[0002] In the development of communication technology, laser communication technology has become the key to achieving high-speed and long-distance communication. Using a laser beam to transmit data has the advantages of a narrow divergence angle and high directivity, enabling high-performance optical communication. For example, through laser transmission between various satellites in space, information can be directly transmitted from one satellite to another and finally connected to a ground station, which reduces the setting and dispersion range of ground stations and significantly reduces costs.

[0003] In past optical transmission systems, light-emitting diodes or lasers were generally selected as the light-emitting elements. Among them, the light-emitting diode light source has a large spectral bandwidth and poor beam quality, which limits its application in long-distance and high-speed transmission. The laser source has a narrow divergence angle and good beam quality, which helps to improve the transmission rate and optical communication ability.

[0004] Polarization multiplexing is an efficient technology in the field of optical communication. It can transmit multiple independent information streams in the same optical communication signal, effectively expanding the transmission capacity and efficiency. However, in practical applications, the system cost and complexity are often increased due to complex optical systems (including light-emitting elements, polarization controllers, beam splitters, detectors, etc.). Summary of the Utility Model

[0005] The utility model provides a photonic crystal surface emitting laser element, which can achieve good optical transmission effects with a simple structure.

[0006] An embodiment of the utility model provides a photonic crystal surface emitting laser element, including a photonic crystal surface emitting laser chip and a metasurface. The photonic crystal surface emitting laser chip has a light-emitting surface and includes a photonic crystal layer, wherein the photonic crystal layer includes a plurality of right-angled triangular prism-shaped holes arranged in an array, and the inclined surfaces of these right-angled triangular prism-shaped holes are parallel to each other. The metasurface is monolithically integrated onto the light-emitting surface of the photonic crystal surface emitting laser chip.

[0007] According to an embodiment of the utility model, the metasurface has a symmetry axis, and a plurality of metaatoms on both sides of the symmetry axis of the metasurface are symmetric to each other, and the normal of the inclined surface of the right-angled triangular prism-shaped hole is parallel to the symmetry axis.

[0008] According to an embodiment of the present invention, the metasurface has a plurality of meta-atoms, and the arrangement of the plurality of meta-atoms is non-mirror symmetric.

[0009] According to an embodiment of the present invention, the plurality of right triangular prism-shaped holes are a plurality of isosceles right triangular prism-shaped holes.

[0010] According to an embodiment of the present invention, the plurality of right triangular prism-shaped holes are arranged on square lattice points.

[0011] According to an embodiment of the present invention, the photonic crystal surface emitting laser chip further includes: a substrate having the light emitting surface and an opposite surface relative to the light emitting surface; a doped semiconductor layer disposed on the opposite surface; and a light emitting layer disposed on the doped semiconductor layer, wherein the photonic crystal layer is disposed on the light emitting layer.

[0012] According to an embodiment of the present invention, the light from the photonic crystal layer is linearly polarized light, and the metasurface has a plurality of meta-atoms, and the plurality of meta-atoms are configured to split the linearly polarized light into left-handed circularly polarized light and right-handed circularly polarized light emitted in different directions.

[0013] According to an embodiment of the present invention, it further includes another plurality of photonic crystal surface emitting laser chips and another plurality of metasurfaces, wherein the another plurality of metasurfaces are respectively monolithically integrated onto the light emitting surfaces of the another plurality of photonic crystal surface emitting laser chips, and the photonic crystal surface emitting laser chips and the another plurality of photonic crystal surface emitting laser chips are arranged in an array.

[0014] According to an embodiment of the present invention, the metasurface and the another plurality of metasurfaces respectively have different meta-atom configurations.

[0015] In the photonic crystal surface emitting laser element according to the embodiment of the present invention, due to the adoption of the photonic crystal surface emitting laser chip and the metasurface monolithically integrated onto its light emitting surface, a good optical transmission effect can be achieved with a simple structure. For example, polarization multiplexing can be achieved with a simple structure, and then high-efficiency optical communication can be achieved.

[0016] To make the above features and advantages of the present invention more obvious and understandable, specific embodiments are hereinafter given and described in detail in conjunction with the accompanying drawings as follows. Description of the Drawings

[0017] Figure 1A A three-dimensional schematic diagram of a photonic crystal surface emitting laser element according to an embodiment of the present invention;

[0018] Figure 1B For Figure 1ASchematic three-dimensional view of a photonic crystal surface-emitting laser element after being longitudinally cut along the line I-I;

[0019] Figure 2A is Figure 1A Schematic three-dimensional view of a photonic crystal surface-emitting laser element with a partial cut to expose the photonic crystal layer;

[0020] Figure 2B is Figure 1A Top view schematic of the photonic crystal layer in;

[0021] Figure 3 is Figure 1A Top view schematic of the metasurface in;

[0022] Figure 4A Partial three-dimensional schematic of a photonic crystal surface-emitting laser element according to another embodiment of the present invention;

[0023] Figure 4B is Figure 4A Top view schematic of the photonic crystal surface-emitting laser element of. Detailed implementation manners

[0024] Figure 1A Three-dimensional schematic of a photonic crystal surface-emitting laser element according to an embodiment of the present invention, Figure 1B is Figure 1A Schematic three-dimensional view of the photonic crystal surface-emitting laser element of after being longitudinally cut along the line I-I, Figure 2A is Figure 1A Schematic three-dimensional view of the photonic crystal surface-emitting laser element of with a partial cut to expose the photonic crystal layer, Figure 2B is Figure 1A Top view schematic of the photonic crystal layer in, while Figure 3 is Figure 1A Top view schematic of the metasurface in. Please refer to Figure 1A , Figure 1B , Figure 2A , Figure 2B and Figure 3 , the photonic crystal surface-emitting laser element 100 of this embodiment includes a photonic crystal surface-emitting laser chip 200 and a metasurface 300. The photonic crystal surface-emitting laser chip 200 has a light-emitting surface 202 and includes a photonic crystal layer 210, wherein the photonic crystal layer 210 includes a plurality of right-angled triangular prism-shaped holes 212 arranged in an array (as shown in Figure 2A and Figure 2B ), and the inclined surfaces 211 of these right-angled triangular prism-shaped holes 212 are parallel to each other. That is to say, this right-angled triangle includes two right-angled sides and a hypotenuse, and the inclined surface 211 is the surface where the hypotenuse is located. The metasurface 300 is monolithically integrated onto the light-emitting surface 202 of the photonic crystal surface-emitting laser chip 200.

[0025] In this embodiment, these right-angled triangular prism-shaped holes 212 are a plurality of isosceles right-angled triangular prism-shaped holes. In addition, in this embodiment, these right-angled triangular prism-shaped holes 212 are arranged on square lattice points.

[0026] In this embodiment, the metasurface 300 has a plurality of meta-atoms 310, and the metasurface 300 has a symmetry axis 302. These meta-atoms 310 of the metasurface 300 on both sides of the symmetry axis 302 are symmetric with each other, and the normal 213 of the inclined surface 211 of the right-angled triangular prism-shaped hole 212 (as Figure 2B shown) is parallel to the symmetry axis 302, where both the normal 213 and the symmetry axis 302 are parallel to the light-emitting surface 202. In this embodiment, the light L from the photonic crystal layer 210 is linearly polarized light, and its polarization direction is, for example, parallel to the direction of the normal 213. These meta-atoms 310 of the metasurface 300 are configured to split this linearly polarized light (i.e., the light L) into a left-handed circularly polarized light L1 and a right-handed circularly polarized light L2 that are emitted in different directions. In this embodiment, since the normal 213 is parallel to the symmetry axis 302, the energies of the left-handed circularly polarized light L1 and the right-handed circularly polarized light can be evenly distributed. Each meta-atom 310 is, for example, a column with a long strip-shaped top surface and standing vertically on the light-emitting surface 202, and the arrangement of these meta-atoms 310 is designed in a geometric phase manner. However, the present utility model does not limit that the metasurface 300 needs to have a symmetry axis 302. That is to say, in other embodiments, the arrangement of these meta-atoms 310 of the metasurface 300 can also be non-mirror symmetric.

[0027] In the photonic crystal surface-emitting laser element 100 of this embodiment, since the photonic crystal surface-emitting laser chip 200 and the metasurface 300 monolithically integrated on its light-emitting surface 202 are adopted, a good optical transmission effect can be achieved with a simple architecture. For example, polarization multiplexing (such as generating a left-handed circularly polarized light L1 and a right-handed circularly polarized light L2) can be achieved with a simple architecture, thereby achieving efficient optical communication. Specifically, the metasurface 300 has the characteristics of high efficiency, thinness, and lightness, providing planar optics to replace large traditional diffraction optical elements (DOEs), polarization controllers, or beam splitters, etc. In addition, the metasurface 300 can be designed to assign independent phases to orthogonal linearly polarized lights, and can simultaneously control beam deflection on the basis of polarization control. In addition, since the divergence angle of the light L emitted by the photonic crystal surface-emitting laser chip 200 is small, the overall light-emitting efficiency can be effectively improved when combined with the metasurface 300.

[0028] Furthermore, in the photonic crystal surface emitting laser element 100 of this embodiment, by introducing geometric phase to design the metaatom 310, the designed metaatom 310 will depend on its polarization conversion efficiency. High polarization conversion efficiency helps to improve the overall efficiency of the element. This design method can provide unique phase control for orthogonal linearly polarized states, convert linearly polarized incident light (i.e., light L) for polarization, and simultaneously generate left-handed and right-handed circularly polarized lights L1 and L2, and has a beam deflection function, replacing multiple optical elements such as beam splitters and beam controllers. In addition, the method of monolithically integrating the metasurface 300 with the photonic crystal surface emitting laser chip 200 proposed in this embodiment provides a solution for a compact functional laser beam generating device.

[0029] In addition, in the photonic crystal surface emitting laser element 100 of this embodiment, the designed corresponding metasurface 300 is directly fabricated on the photonic crystal surface emitting laser chip 200 through semiconductor processes (such as lithography) (for example, the metasurface 300 is directly fabricated on the substrate 220 by lithography). This method does not need to consider refractive index matching, can reduce transmission loss, and compared with the transmission of independent optical elements, the efficiency is increased by 45%. In terms of volume, in addition to not relying on spatial propagation to accumulate phase, and the metasurface 300 is a single-layer nanostructure, so compared with diffractive optical elements, the overall element volume can be effectively reduced.

[0030] In the photonic crystal surface emitting laser element 100 of this embodiment, the metasurface 300 realizes the conversion of a linearly polarized beam (i.e., light L) into left-handed and right-handed circularly polarized lights L1 and L2. Different polarization states are different channels, achieving multi-channel polarization multiplexing to expand the transmission capacity, and simultaneously having a beam deflection function. Combined with polarization multiplexing, a free space optical communication system is completed.

[0031] In this embodiment, the photonic crystal surface emitting laser chip 200 further includes a substrate 220, a doped semiconductor layer 230, and a light emitting layer 240. The substrate 220 has a light emitting surface 202 and an opposite surface 204 relative to the light emitting surface 202. The doped semiconductor layer 230 is disposed on the opposite surface 204. The light emitting layer 240 is disposed on the doped semiconductor layer 230, wherein the photonic crystal layer 210 is disposed on the light emitting layer 240. In this embodiment, the photonic crystal surface emitting laser chip 200 further includes a doped semiconductor layer 250, a first electrode 260, and a second electrode 270, wherein the doped semiconductor layer 250 is disposed on the photonic crystal layer 210, and the first electrode 260 is disposed on the light emitting surface 202 but exposes the metasurface 300. In addition, the second electrode 270 is disposed on the doped semiconductor layer 250. In this embodiment, the doped semiconductor layer 230 is, for example, an N-type semiconductor layer, and the photonic crystal layer 210 and the doped semiconductor layer 250 are, for example, P-type semiconductor layers. However, in other embodiments, the doped semiconductor layer 230 may be a P-type semiconductor layer, and the photonic crystal layer 210 and the doped semiconductor layer 250 may be N-type semiconductor layers. Additionally, the light emitting layer 240 is, for example, a quantum well layer or a multi-quantum well layer. When a forward voltage is applied between the second electrode 270 and the first electrode 260, the light emitting layer 240 emits light L. Then, after the light L resonates in the photonic crystal layer 210, linearly polarized light (i.e., light L) is formed. Then, the light L is transmitted to the metasurface 300, and the metasurface 300 splits the light L into left-handed circularly polarized light L1 and right-handed circularly polarized light L2.

[0032] Figure 4A is a partial perspective view of a photonic crystal surface emitting laser element according to another embodiment of the present invention, and Figure 4B is Figure 4A a top view of the photonic crystal surface emitting laser element. Please refer to Figure 4A and Figure 4B , the photonic crystal surface emitting laser element 100a of this embodiment is similar to Figure 1A the photonic crystal surface emitting laser element 100, and the main differences between the two are described as follows. Figure 1A The photonic crystal surface emitting laser element 100 of Figure 4A and Figure 4B has a photonic crystal surface emitting laser chip 200 and a metasurface 300, while Figure 1AThe photonic crystal surface-emitting laser element 100 further includes a plurality of additional photonic crystal surface-emitting laser chips 200 and a plurality of additional metasurfaces 300, wherein the plurality of additional metasurfaces 300 are respectively monolithically integrated onto the light-emitting surfaces 202 of the plurality of additional photonic crystal surface-emitting laser chips 200. In addition, the photonic crystal surface-emitting laser chips 200 and the plurality of additional photonic crystal surface-emitting laser chips 200 are arranged in an array, for example, a two-dimensional array. In this embodiment, the metasurfaces 300 and the plurality of additional metasurfaces 300 respectively have different metaatom configurations. In this way, the different metasurfaces 300 can split the light L into left-handed circularly polarized light L1 and right-handed circularly polarized light L2 with different angles. By independently controlling each of the photonic crystal surface-emitting laser chips 200 through the driving lines 102 and 104, the photonic crystal surface-emitting laser element 100 can form outgoing light with different deflection angles according to actual needs.

[0033] In summary, in the photonic crystal surface-emitting laser element of the embodiment of the present utility model, due to the adoption of the photonic crystal surface-emitting laser chip and the metasurface monolithically integrated onto its light-emitting surface, a good optical transmission effect can be achieved with a simple structure. For example, polarization multiplexing can be achieved with a simple structure, and thus high-efficiency optical communication can be achieved.

[0034] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present utility model and are not intended to limit them; although the present utility model has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present utility model.

Claims

1. A photonic crystal surface-emitting laser element, characterized in that: include: A photonic crystal surface-emitting laser chip having a light-emitting surface and comprising a photonic crystal layer, wherein the photonic crystal layer comprises a plurality of right-angled triangular prism-shaped holes arranged in an array, and the inclined surfaces of the plurality of right-angled triangular prism-shaped holes are parallel to each other; and The metasurface is monolithically integrated onto the light emitting surface of the photonic crystal surface-emitting laser chip.

2. The photonic crystal surface emitting laser element according to claim 1, wherein: The metasurface has a symmetry axis, a plurality of metaatoms of the metasurface on both sides of the symmetry axis are symmetrical to each other, and a normal line of the inclined surface of the right-angled triangular prism-shaped hole is parallel to the symmetry axis.

3. The photonic crystal surface emitting laser element according to claim 1, wherein: The metasurface has a plurality of metaatoms, and the arrangement of the plurality of metaatoms is non-mirror symmetric.

4. The photonic crystal surface emitting laser element according to claim 1, wherein: The plurality of right-angled triangular prism-shaped holes are a plurality of isosceles right-angled triangular prism-shaped holes.

5. The photonic crystal surface emitting laser element according to claim 1, wherein: The plurality of right-angled triangular prism-shaped holes are arranged on square lattice points.

6. The photonic crystal surface emitting laser element according to claim 1, wherein: The photonic crystal surface-emitting laser chip further comprises: A substrate having the light emitting surface and an opposite surface relative to the light emitting surface; a doped semiconductor layer disposed on the opposite surface; and The light-emitting layer is configured on the doped semiconductor layer, wherein the photonic crystal layer is configured on the light-emitting layer.

7. The photonic crystal surface emitting laser element according to claim 1, wherein: The light from the photonic crystal layer is linearly polarized light, and the metasurface has a plurality of metaatoms, which are configured to split the linearly polarized light into left-handed circularly polarized light and right-handed circularly polarized light emitted in different directions.

8. The photonic crystal surface emitting laser element according to claim 1, wherein: It also includes a plurality of additional photonic crystal surface emitting laser chips and a plurality of additional metasurfaces, wherein the plurality of additional metasurfaces are respectively integrated into the light emitting surfaces of the plurality of additional photonic crystal surface emitting laser chips, and the photonic crystal surface emitting laser chip and the plurality of additional photonic crystal surface emitting laser chips are arranged in an array.

9. The photonic crystal surface emitting laser element according to claim 8, characterized in that: The metasurface and the other plurality of metasurfaces have different metaatom configurations.

Images