Miniaturized module integrated with super-lens surface emitting laser and electronic equipment comprising same

Abstract

The utility model relates to a surface emitting laser miniaturized module integrated with a super lens and electronic equipment comprising the surface emitting laser miniaturized module. According to one embodiment, the surface emitting laser module integrated with the super lens can comprise a surface emitting laser which comprises a photonic crystal surface emitting laser or a topological cavity surface emitting laser, and the surface emitting laser is provided with a light emitting surface; and the super lens is integrated at the light emitting surface of the surface emitting laser.

Description

Technical Field

[0001] The utility model generally relates to the field of optoelectronic devices, and more particularly, to a surface-emitting laser module with an integrated superlens, which can realize the miniaturization, planarization and integration of semiconductor laser modules. Background Art

[0002] Semiconductor lasers have been widely used in many fields such as communications, medical treatment, display, and material processing due to their advantages such as small size, high efficiency, low power consumption, long life, and low cost. However, the laser chip itself is generally difficult to use alone, and needs to be coordinated with various optical components, such as lenses, prisms, diffraction elements, polarization elements, etc., to form a laser module so that the emitted light beam meets the application requirements. These optical components are not only much larger than semiconductor laser chips, but their manufacturing and packaging costs often exceed the laser chip itself, making it difficult to further reduce the size and price of the entire semiconductor laser module, which limits the more integrated and lower-cost application of semiconductor laser light sources.

[0003] The volume of a laser module can be calculated as the product of the light emission area and the propagation length. The light emission area is generally determined by the application requirements and the diffraction limit and cannot be reduced. For example, the divergence angle of the light beam and the far-field resolution are determined by the near-field area, so the further miniaturization of the laser module can only rely on reducing the propagation length. At present, the propagation length required for the laser module is mainly used for beam expansion and shaping of semiconductor laser spots. The reason is that the output aperture of the semiconductor laser chip is generally much smaller than the output aperture required by the application. For example, the beam aperture of the lattice structure laser module used for face recognition is about 2 mm, while the near-field spot of a single vertical cavity surface emitting laser (VCSEL) is about 10 microns, which requires a longer propagation distance to complete the beam expansion. Figure 1A This is a schematic diagram of the structure of a traditional semiconductor laser module. Figure 1A As shown, multiple vertical cavity surface emitting lasers (VCSELs) 101 can be arranged in an array to provide beams with sufficiently high power. Multiple optical elements are arranged above the multiple VCSELs 101, such as a lens group formed by multiple lenses 102a, 102b and 102c, and a diffractive optical element (DOE) 102d. Figure 1A In the example shown, in order to provide an output light spot of approximately 2 mm×2 mm, a propagation length of more than 3 mm is required, so the volume of the entire laser module is relatively large. Figure 1BThe schematic diagram of the structure of a semiconductor laser module including the latest developed metalens (also called metasurface) 103 is shown. Metalens is a planar optical technology that can replace traditional passive optical elements such as concave lenses and convex lenses. The thickness can be reduced to the wavelength level, but this is still very limited in reducing the size of existing laser modules, because a long propagation distance is still required between the laser and the metalens for beam expansion, and the size of the laser module is still determined by the aperture of the output light spot. Figure 1B As shown, when the same array of vertical cavity surface emitting lasers 101 is used, in order to provide an output light spot of about 2 mm×2 mm, the beam propagation length used for beam expansion is still about 3 mm, so the volume reduction of the entire laser module is very limited.

[0004] In addition, directly integrating a superlens on the light-emitting surface of a vertical cavity surface emitting laser cannot improve the size of the laser module, because the emission area of ​​a single vertical cavity surface emitting laser 101 is too small, and the emitted light beam is far from meeting the requirements of practical applications, and still requires a larger beam expansion distance. Therefore, the fundamental obstacle to the miniaturization of laser modules is the lack of high-performance semiconductor lasers whose near-field spot can match the required emission aperture. Utility Model Content

[0005] The utility model provides a miniaturized module of an integrated superlens surface emitting laser, which can solve one or more of the above-mentioned technical problems. The utility model directly integrates a superlens on the light-emitting surface of a photonic crystal surface emitting laser or a topological cavity surface emitting laser. Both the photonic crystal surface emitting laser and the topological cavity surface emitting laser can provide large-area single-mode lasers, with millimeter-level aperture and watt-level output power, and the superlens can regulate the outgoing light field at any degree of freedom such as phase, polarization, and exit angle to achieve the desired exit light beam. Therefore, the utility model provides the possibility of simplifying and reducing the laser module. The superlens can be directly integrated into the light-emitting surface of the photonic crystal surface emitting laser or the topological cavity surface emitting laser, for example, a micro-nano structure is directly etched in the semiconductor layer of the exit surface to form a superlens, or an additional superlens layer can be deposited on the light-emitting surface of the photonic crystal surface emitting laser or the topological cavity surface emitting laser, and a micro-nano structure is etched in the superlens layer to form a superlens, or a micro-nano structure can be directly deposited, grown or epitaxially extended on the light-emitting surface of the surface emitting laser to form a superlens. The utility model can provide a high-performance semiconductor laser with a near-field light spot matching the required emission aperture, realize the planarization and integration of the entire semiconductor laser light source, and its volume is reduced by more than one order of magnitude compared with the existing semiconductor laser module.

[0006] According to an exemplary embodiment, a surface emitting laser module with an integrated superlens is provided, comprising: a surface emitting laser, including a photonic crystal surface emitting laser or a topological cavity surface emitting laser, wherein the surface emitting laser has a light emitting surface; and a superlens integrated at the light emitting surface of the surface emitting laser.

[0007] In an exemplary embodiment, an upper surface of a top layer of the surface emitting laser serves as a light exiting surface of the surface emitting laser, and the superlens includes a nanorod structure formed in the upper surface of the top layer.

[0008] In an exemplary embodiment, the top layer of the surface emitting laser is a semiconductor layer, an insulating layer or a metal layer.

[0009] In an exemplary embodiment, an upper surface of a top layer of the surface emitting laser is used as a light exiting surface of the surface emitting laser, and the superlens includes a nanorod structure formed above the top layer.

[0010] In an exemplary embodiment, the nanopillar structure is formed in a superlens layer located above the top layer of the surface emitting laser, the superlens layer is etched partially or entirely through the thickness to form the nanopillar structure, or the nanopillar structure is formed by depositing, growing or epitaxially growing the nanopillar structure directly on the top layer of the surface emitting laser.

[0011] In an exemplary embodiment, the nanorod structure includes a semiconductor material, an insulator material or a metal material.

[0012] In an exemplary embodiment, the nanorod structure includes one or more of amorphous silicon, titanium dioxide, silicon nitride, and silicon oxide.

[0013] In an exemplary embodiment, the metalens includes rectangular or elliptical nanorod structures arranged in a triangular lattice or a tetragonal lattice, and each nanorod structure has a height h, a length l, a width s, and a rotation angle θ.

[0014] In an exemplary embodiment, one or more of the height h, length l, width s, and rotation angle θ of the nanorod structure is modulated to adjust the phase, intensity and / or direction of the laser light emitted from the surface emitting laser module.

[0015] According to an exemplary embodiment, an electronic device is provided, comprising the above-mentioned surface emitting laser module.

[0016] The above and other features and advantages of the present invention will become apparent from the following description of exemplary embodiments with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1A The present invention is a schematic diagram of the structure of an existing semiconductor laser module.

[0018] Figure 1B It is a schematic diagram of the structure of another existing semiconductor laser module.

[0019] Figure 2 It is a schematic structural diagram of a semiconductor laser module according to an exemplary embodiment of the utility model.

[0020] Figure 3 It is a schematic diagram of the layered structure of a semiconductor laser module according to an exemplary embodiment of the utility model.

[0021] Figure 4 It is a schematic diagram of the layered structure of a semiconductor laser module according to another exemplary embodiment of the utility model.

[0022] Figure 5 is a schematic diagram of a nanocolumn structure forming a superlens according to an exemplary embodiment of the present utility model.

[0023] Figure 6 It is a curve showing the relationship between the parameters of the nanocolumn structure of the superlens and the regulation of the phase, wavelength and transmittance of the outgoing light beam.

[0024] Figure 7 This is an electron micrograph of the nanopillar structure that forms the superlens.

[0025] Figure 8 The semiconductor laser module of the utility model is used to realize the point cloud structure and the simulation pattern and experimental photograph of the far-field pattern. DETAILED DESCRIPTION

[0026] Exemplary embodiments of the present invention will be described below with reference to the accompanying drawings. Note that the accompanying drawings may not be drawn to scale.

[0027] Figure 2 Schematic diagram of the structure of a semiconductor laser module according to an exemplary embodiment of the present utility model. Figure 2 As shown, the semiconductor laser module includes a surface emitting laser 210, which can be a photonic crystal surface emitting laser (PCSEL) or a topological cavity surface emitting laser (TCSEL), and its specific structure will be discussed in detail below. The surface emitting laser 210 has a light emitting surface, Figure 2The upper surface in the middle is the metalens 201 integrated at the light-emitting surface of the surface-emitting laser 210. Compared with the traditional vertical cavity surface-emitting laser (VCSEL), the photonic crystal surface-emitting laser (PCSEL) and the topological cavity surface-emitting laser (TCSEL) can provide a larger light-emitting surface, for example, a millimeter-level aperture. Therefore, integrating the metalens 201 on a single surface-emitting laser 210 can manipulate the output light field in any degree of freedom and provide a good coherent light source. Figure 2 In the embodiment, for example, a PCSEL or TCSEL laser with a size of about 1 mm×1 mm is selected to achieve Figure 1A and Figure 1B The laser module based on the VCSEL array shown in the figure has a comparable output beam aperture, and the thickness of the laser module can be reduced to about 0.3 mm. Therefore, the volume of the entire laser module can be reduced by more than an order of magnitude, realizing the planarization and integration of the entire semiconductor laser light source.

[0028] Figure 3 FIG. 1 is a schematic diagram of a layered structure of a semiconductor laser module according to an exemplary embodiment of the present utility model. Figure 3 As shown, the semiconductor laser module may include a bottom electrode layer 212, a first semiconductor layer 214, an active layer 216, a second semiconductor layer 218 and a top electrode layer 220, which constitute Figure 2The surface emitting laser 210 shown. The first semiconductor layer 214 and the second semiconductor layer 218 may have different conductivity types, for example, the first semiconductor layer 214 may be an N-type doped semiconductor layer, and the second semiconductor layer 218 may be a P-type doped semiconductor layer, or vice versa, so as to respectively inject N-type carriers and P-type carriers into the active layer 216. For a photonic crystal surface emitting laser (PCSEL), the active layer 216 includes a photonic crystal layer formed therein or near it (for example, at the upper surface or the lower surface), which includes a semiconductor material and a spatial periodic structure formed by materials with different refractive indices, such as air, in the semiconductor material, wherein the air holes are arranged in a spatial periodic manner, so that the refractive index of light is periodically distributed, and an energy band structure is generated when light propagates therein, and the photon frequency in the band gap is prohibited from propagating, and this characteristic is used to prepare a high-efficiency zero-threshold semiconductor laser. For the topological cavity surface emitting laser (TCSEL), the active layer 216 similarly also includes a photonic crystal layer formed therein or near it (for example, at the upper surface or the lower surface), wherein the photonic crystal supercell structure is further modulated in two independent dimensions to produce a vortex-type structural change around the cavity center of the photonic crystal cavity, thereby opening the Dirac point in the energy band when the photonic crystal supercell is in the equilibrium position, and therefore it can also be called a topological photonic crystal layer. The specific structure and principle of the topological cavity surface emitting laser (TCSEL) can be found in the applicant's prior invention patent CN201911035379.9, which will not be described in detail here. For simplicity here, in Figure 3 Only the active layer 216 is shown, and a separate photonic crystal layer or a topological photonic crystal layer is not shown, but it should be understood that a photonic crystal layer or a topological photonic crystal layer is formed in or near the active layer 216 .

[0029] Continue to refer to Figure 3 , the bottom electrode layer 212 and the top electrode layer 220 may be formed of a conductive metal material. In order to facilitate laser emission, the top electrode layer 220 may be formed in a ring shape; in other embodiments, the top electrode layer 220 may also be formed in a porous structure or a mesh structure. Alternatively, when the top electrode layer 220 is formed of a transparent conductive material such as IZO or ITO, the top electrode layer 220 may also be formed as a complete layer. For another example, the top electrode layer 220 may also include a very thin metal layer so that the laser can be emitted through the top electrode layer 220.

[0030] It should be understood that Figure 3Only the basic layer structures of the photonic crystal surface emitting laser (PCSEL) and the topological cavity surface emitting laser (TCSEL) are shown, and they may also include various additional layers, such as Bragg reflection layers, buffer layers, protective layers, etc. The utility model is not limited to photonic crystal surface emitting lasers (PCSEL) and topological cavity surface emitting lasers (TCSEL) of specific structures, but photonic crystal surface emitting lasers (PCSEL) and topological cavity surface emitting lasers (TCSEL) of various structures can be used as the surface emitting laser 210 in the semiconductor laser module of the utility model. It should be understood that various existing or future developed topological cavity surface emitting lasers (TCSEL) and topological cavity surface emitting lasers (TCSEL) can be applied to the miniaturized module of the integrated superlens surface emitting laser of the present application as long as they can provide a near-field spot size that meets the application requirements.

[0031] exist Figure 3 In the illustrated embodiment, since the top electrode layer 220 is formed in a ring shape, the second semiconductor layer 218 can be regarded as the top layer of the surface emitting laser 210, and its upper surface is used as the light emitting surface of the surface emitting laser 210. The superlens 201 can be integrated in the upper surface of the second semiconductor layer 218, including a nano-pillar structure formed in the surface, which will be described in detail below. In other embodiments, the top layer of the surface emitting laser 210, that is, the layer constituting the light emitting surface, can be other layers, such as other semiconductor layers, or can be an insulating protective layer, a metal layer used as a top electrode, etc. In this case, the superlens 201 can be integrated in the upper surface of such a conductor layer, insulating protective layer or top electrode metal layer. For example, the top layer of the surface emitting laser 210 can be directly etched to form the nano-pillar structure of the superlens 201, and only a portion of the depth of the top layer can be etched, or the entire depth of the top layer can be etched without affecting the original function of the top layer.

[0032] Figure 4 FIG. 1 is a schematic diagram of a layered structure of a semiconductor laser module according to another exemplary embodiment of the present invention. Figure 4 In the embodiment shown, the structure of the surface emitting laser 210 is similar to Figure 3 The embodiments shown are substantially the same, including a bottom electrode layer 212, a first semiconductor layer 214, an active layer 216, a second semiconductor layer 218, and a top electrode layer 220, and repeated descriptions of these layers will be omitted herein. Figure 4 The semiconductor laser module further includes a top layer ( Figure 4 In the figure, the super lens layer 202 is formed on the second semiconductor layer 218, wherein the nano-pillar structure of the super lens 201 is formed on the upper surface of the super lens layer 202. Here, the super lens layer 202 can also be regarded as a part of the super lens 201. Figure 4It is shown that only a portion of the thickness of the super lens layer 202 is etched to form the nano column structure, but in other embodiments, the entire thickness of the super lens layer 202 can also be etched to form the nano column structure, that is, the super lens layer 202 and the nano column structure are the same layer. Figure 4 In the illustrated embodiment, the superlens layer 202 is directly deposited on the top layer of the surface emitting laser 210; in other embodiments, a transparent intermediate layer may also exist between the superlens layer 202 and the top layer of the surface emitting laser 210. Here, integrating the superlens 201 into the light-emitting surface of the surface emitting laser means that the two are in direct or indirect contact, but there is no interval or gap for beam expansion as in the prior art. The superlens layer 202 may include semiconductor materials, insulator materials, or metal materials, examples of which include but are not limited to one or more of amorphous silicon, titanium dioxide, silicon nitride, and silicon oxide. In one embodiment, in order to form a good interface with the second semiconductor layer 218 below to reduce reflection, the superlens layer 202 may include a silicon material, such as commonly used amorphous silicon.

[0033] Apart from Figure 4 In addition to first forming the superlens layer 202 and then etching out the nanocolumn structure to form the superlens 201, in other embodiments, the nanocolumn structure can also be directly deposited, grown, or epitaxially grown on the light-emitting surface of the surface-emitting laser 210. For example, a sacrificial layer such as a photoresist layer can be formed on the light-emitting surface of the surface-emitting laser 210, and an opening of a desired pattern can be formed therein by a photolithography or etching process to expose the light-emitting surface below, and then the nanocolumn structure is deposited, grown, or epitaxially grown, and finally the sacrificial layer such as the photoresist layer is removed to leave the superlens 201 formed by the nanocolumn structure.

[0034] In some exemplary embodiments, the superlens 201 can be directly formed on the top layer of the surface emitting laser 210 or the upper surface of the superlens layer 202 located thereon by an etching process. Therefore, the step of forming the superlens 201 can be integrated in the process of forming the surface emitting laser 210, and finally a single surface emitting laser 210 is cut out. In this way, the surface emitting laser 210 and the superlens 201 integrated thereon can be formed in a self-aligned manner. In other embodiments, after the surface emitting laser 210 is manufactured and a single surface emitting laser 210 is cut out, the top layer of the surface emitting laser 210 can be etched, or a superlens layer can be deposited and etched thereon to prepare the superlens 201. The utility model avoids bonding the pre-prepared superlens to the surface emitting laser 210 in a patch manner, which is simpler in process, and the patch bonding method will have additional packaging alignment costs, unnecessary waste of volume and substrate materials, and reflection problems at the interface.

[0035] Refer to above Figure 3 and Figure 4 In the various embodiments described, a protective layer may also be formed on the superlens 201 to protect the nanorod structure of the superlens 201. Such a protective layer may be formed of a transparent material, and its refractive index is different from the refractive index of the material forming the superlens 201, for example, it may be significantly greater than or less than the refractive index of the material forming the superlens 201.

[0036] It should be understood that throughout this application, the nanocolumn structure of the superlens 201 also covers the formation of nanopores, and the nanopores can be regarded as nanocolumns formed by air or vacuum. For example, the superlens layer 202 can be formed first, and then the nanopore structure can be etched therein. The modulation principle of the nanopore on light is the same as that of the nanocolumn, which will not be repeated here. Therefore, when a nanocolumn is mentioned in this application, it can also include a nanopore.

[0037] Figure 5 FIG. 2 is a schematic diagram of a nanorod structure forming a superlens 201 according to an exemplary embodiment of the present invention. Figure 5 As shown, the superlens 201 may include a rectangular nanorod structure, but the nanorod structure may also have other shapes, such as but not limited to an elliptical shape. A plurality of nanorod structures may be arranged periodically, such as in a two-dimensional triangular lattice (e.g. Figure 5 The nanorod structure may have a height h, a length l, and a width s (as shown in the left figure of FIG. 1 ) or a tetragonal lattice (not shown) arranged periodically, with an arrangement period of P. Each nanorod structure may have a height h, a length l, and a width s (as shown in FIG. Figure 5 The nanopillar structure may have a rotation angle θ (not shown), which is the rotation angle of the nanopillar structure relative to a predetermined reference direction in the two-dimensional plane of the arrangement. One or more of the height h, length l, width s, and rotation angle θ of the nanopillar structure may be modulated to adjust the phase, intensity, and / or direction of the laser emitted from the surface emitting laser module. Figure 5 Taking the rectangular nanocolumn structure shown in the figure as an example, the material is amorphous silicon, the refractive index is 3.34, and it is located on the second semiconductor layer 218 formed by InP. When a beam of light is incident on the nanocolumn structure along the z direction, the outgoing light field With the incident light field The relationship can be expressed as:

[0038]

[0039] where t l and t s is the transmission coefficient of light polarized along the l direction and along the s direction is the rotation matrix, θ is the angle between the slow axis of the nanorod and the predetermined x-axis direction. inUnder certain conditions, by selecting the parameters l, s and θ, the nanorod can convert any incident light field E to in Modulated to an output light field E with arbitrary phase and polarization out The photonic crystal surface emitting laser (PCSEL) and the topological cavity surface emitting laser (TCSEL) used as the surface emitting laser 210 are both single-mode lasers with a certain incident phase and polarization, so the combination of the superlens 201 and the surface emitting laser 210 can emit an output light beam with arbitrary phase and polarization.

[0040] Taking the topological cavity surface emitting laser (TCSEL) as an example, the light beam emitted after passing through the resonant cavity is a radially polarized vector beam. In order to obtain a higher quality dot cloud and a clearer hologram in the application, the polarization of the light beam must be adjusted to be consistent. Taking the modulation into circularly polarized light as an example, a series of combinations of side lengths l and s need to be selected so that The angle between the rotation angle θ of the nanorod and the polarization direction is selected as π / 4, so that the rectangular nanorod acts as a quarter wave plate, which can adjust the linear polarization of the vector beam to circular polarization. The phase ranges from 0 to 2π, allowing circularly polarized light to have any output phase.

[0041] In order to ensure that there is no high-order reflection, the arrangement period P of the nanorod structure should be less than where n InP is the refractive index of InP, the period P is selected to be, for example, 558 nm, the height h of the nanocolumn is 1.5 μm, the length of the short side s of the rectangle is in the range of 100 nm to 300 nm, and the length of the long side l is in the range of 300 nm to 400 nm. Then, according to the Fourier iteration algorithm, the emission phase at different positions is designed. The corresponding relationship between the rectangular parameters, the emission intensity, and the emission phase is as follows: Figure 6 As shown, it can be seen that its transmittance is substantially over 80%, surpassing the 73% transmittance of the InP substrate itself into the air, which means that the surface integration of the superlens 201 also plays the role of an anti-reflection film.

[0042] Figure 72 is an electron micrograph of a nanocolumn structure forming a superlens 201. This example is a nanocolumn structure obtained by electron beam exposure and dry etching process after amorphous silicon is deposited on an InP substrate (e.g., the second semiconductor layer 218). The selection of amorphous silicon to form a superlens is based on a comprehensive consideration of processing difficulty and modulation efficiency. However, in other embodiments, other materials may be used or the nanocolumn structure may be formed by etching directly on the top layer of the surface emitting laser 210 (e.g., the InP semiconductor layer or the top electrode metal layer). The processing accuracy mainly depends on the etching accuracy. When the superlens 201 is formed in the top electrode metal layer formed as a continuous layer, the top electrode metal layer simultaneously plays the role of modulating the light beam and introducing the current, making the current injection more uniform. However, due to the high light absorption rate of the metal, the transmittance of the outgoing light beam will be affected to a certain extent.

[0043] The semiconductor laser module of the utility model has a very broad application prospect. In an exemplary application scenario, when the semiconductor laser module adopts a TCSEL laser, thanks to the polarization single-mode characteristics of the TCSEL and the polarization control ability of the superlens, the TCSEL laser integrated with the superlens can achieve output with arbitrarily determined polarization, which has great advantages over the multi-mode or polarization-degenerate single-mode VCSEL laser. For example, the TCSEL laser integrated with the superlens can output both the common linearly polarized Gaussian beam and the circularly polarized laser that is generally difficult to achieve on-chip. A more general polarized beam is a cylindrical vector vortex beam (CVVB), which is a cylindrical beam with inconsistent phase and polarization distribution in space, and can be expressed in the form of a Jones vector using two parameters l and m, that is,

[0044]

[0045] This type of light beam has unique optical properties and has potential application prospects in the fields of optical communications, optical trapping, quantum information, etc. In fact, the light beam emitted by the TCSEL laser itself can be regarded as a cylindrical vector vortex beam with l=0, m=1, and the superlens has the ability to adjust arbitrary polarization and phase. Therefore, the TCSEL laser integrated with the superlens can also emit a light beam with arbitrary (l, m). The simplest regulation is to convert the hollow light beam into a high-base mode beam of (l=0, m=0) (which has the widest application scenario). It is only necessary to adjust the polarization of each position to the same direction, and the phase remains unchanged. At this time, the divergence angle is reduced to half of the original, and the laser brightness is increased to 4 times the original. Its M2 factor (that is, the laser beam quality factor) is close to 1, which verifies the single-mode resonance characteristics of the TCSEL laser. At this time, the micro-nano processing pattern of the superlens is as follows: Figure 7 As shown in the middle pattern.

[0046] For the semiconductor laser module of the present application that directly integrates a superlens on a PCSEL or TCSEL laser, in addition to polarization control, the inventors have also studied and demonstrated its applications in structured light control, holographic patterns, etc. A known pattern is projected onto a target object, and the three-dimensional information of the object is obtained by measuring the deformation of the pattern. This technology is called structured light technology and has been widely used in fields such as face recognition and three-dimensional mapping. A common type of structured light is a dense dot matrix, such as the face ID commonly used on mobile phones. At present, the structured light generation module on consumer electronic devices is usually composed of components such as a VCSEL laser array, a lens group, a diffractive optical element, etc., such as Figure 1A As shown in the figure, the laser is collimated and expanded by the lens group and then split by the DOE to form a dot cloud. Depending on the different demand scenarios, the divergence angle of a single emission point is approximately between 0.1° and 1°. To achieve such a small divergence angle, the light exit hole size is usually around 2 mm. In this structure, various optical components need to be strictly aligned and occupy a large volume. To address this problem, Metalenz has launched the Orion product based on the metasurface, such as Figure 1B As shown in the figure, thanks to the arbitrary phase design capability of the metasurface, a layer of metasurface can simultaneously complete the functions of collimation and dot-matrix emission, replacing the bulky lens group and DOE in the traditional module. Although the Orion module has a simpler structure than the traditional module, its volume has not been significantly reduced. This is because the light output aperture of the VCSEL is too small, and a large space is still required between the VCSEL and the metasurface to allow the light beam emitted by the VCSEL to complete beam expansion in order to achieve a small divergence angle for a single emission point. The PCSEL and TCSEL themselves have the characteristics of large light output area and small divergence angle, so after etching the superlens, the steps of beam expansion and collimation can be avoided, and the structured light emission can be completed directly, as shown in the figure. Figure 2 The advantages of the PCSEL and TCSEL laser modules with integrated superlens in the utility model in the dot matrix projector will be specifically described below from five aspects: volume, packaging, dot matrix quality, polarization, and wavelength.

[0047] Volume: As Figure 2 As shown in Figure 1, the PCSEL or TCSEL laser module with integrated superlens has achieved the ultimate in miniaturization. The entire module only requires a semiconductor chip about 100 microns thick, and the chip area is determined by the diffraction limit required by the application. Figure 1A , Figure 1B and Figure 2Compared with traditional modules, the longitudinal thickness of the laser module of the utility model is reduced by about an order of magnitude, and the lateral area is also reduced to about a quarter. The reduction in thickness is due to the large-area single-mode resonant cavity of PCSEL and TCSEL itself. The divergence angle of the emitted laser itself is below 1°, which saves the space for laser beam expansion. The integration of the superlens on the laser's emission surface also reduces the thickness of the optical element to a minimum. The reduction in lateral area is due to the effective coverage of the light beam by the superlens and the high-quality light beams of the PCSEL and TCSEL lasers themselves, which minimizes the lateral light output area to the greatest extent, reaching the limit of the lateral size of the semiconductor laser light source. The reduction of about 40 times in volume will also bring about a significant reduction in weight.

[0048] Packaging: The traditional dot cloud transmitter consists of VCSEL laser array, lens group and DOE and other optical components, such as Figure 1A As shown, in order to ensure the collimation of the light beam and the uniformity of the lattice, strict alignment is required between each optical element and the laser, which has high requirements for packaging. The PCSEL / TCSEL laser module with integrated super lens of the present application is integrated with a single chip, which eliminates the steps of assembling different optical elements and has lower cost. At the same time, traditional packaging methods such as glue bonding will also face problems such as aging of fixtures, poor temperature stability, and interface reflection, while the PCSEL / TCSEL laser module with directly integrated super lens of the present application has a relatively longer life, better stability and better light extraction efficiency.

[0049] Dot quality: The dot distribution based on the VCSEL laser array always inevitably has traces of copying and splicing, which will cause uneven distortion or overlap of the point cloud image at the splicing edge, increasing the difficulty of subsequent algorithm processing. The dot matrix emitted by the PCSEL / TCSEL laser module with integrated superlens of the present application is generated by a beam of collimated light, which can emit a more uniform dot matrix. One of the major advantages of superlens as a diffractive optical element is that it has a smaller modulation unit, so it can have a larger field of view (FOV) than the traditional diffractive optical element DOE. For example, referring to the disclosure of invention patent CN201910430957.2, the metasurface is optimized by the inner point method to complete the uniform dot matrix emission of ±60°. The larger structured light field of view means a wider detection range, which is extremely beneficial for 3D perception. Its principle can also be applied to the metasurface structure of the present application.

[0050] Polarization: Most of the VCSEL laser arrays currently used are multi-mode VCSEL lasers without polarization selectivity, and the far-field emitted by them is also light with uncertain polarization, while PCSEL / TCSEL lasers have a certain single-mode polarization state, and thus the far-field of the PCSEL / TCSEL laser module integrated with a superlens also has a certain polarization. If linearly polarized light or circularly polarized light in a specific direction is emitted, stray light of other polarizations can be filtered out at the receiving end, or polarization information of the detected object can be obtained.

[0051] Wavelength: The PCSEL / TCSEL laser module with integrated superlens of the present application can realize output light of specific wavelength, for example, it can easily realize 1550nm wavelength laser, which has three advantages over the 940nm wavelength which is currently the most widely used in the field of 3D sensing: First, it is safer for human eyes. Compared with 940nm, the human eye safety threshold of 1550nm continuous wave is increased by one to two orders of magnitude, and the pulse peak power threshold is increased by five orders of magnitude. Therefore, higher power output laser can be used with a longer detection distance; second, the 1550nm stray light in the natural environment is relatively weak, and there is a higher contrast during detection, making structured light detection more accurate; third, 1550nm has a higher transmittance for the current mainstream OLED screen, so it has a strong application prospect in exploring the direction of under-screen structured light. Because VCSEL is difficult to achieve long wavelength, the current 1550nm 3D sensing devices mostly use side-emitting DFB (distributed feedback) lasers as light sources. The edge-emitting module is more complex than the surface-emitting module, and the DFB laser emits an elliptical beam, which requires a cylindrical lens for modulation and collimation. Compared with this, the advantages of the PCSEL / TCSEL laser module with an integrated superlens in this application are more obvious.

[0052] The dot matrix structured light is only a representative application case of the PCSEL / TCSEL laser module with integrated superlens in this application. In addition, it can realize a variety of far-field functions, including light deflection, uniform plane light emission, holographic images, etc. The array of PCSEL / TCSEL laser modules with integrated superlens can realize functions such as all-solid-state laser radar by making the laser beam directly obliquely emitted. Its phase design is also very simple. When the deflection angle is When , the phase distribution on the laser surface is Where x is its lateral position, y is its longitudinal position, and λ is its wavelength.

[0053] The PCSEL / TCSEL laser module with integrated superlens of the present application can also efficiently realize a variety of holographic images. There are two requirements for achieving clear holographic patterns. One is to have a sufficiently large coherent light area, and the other is to have precise phase control. These are all possessed by the PCSEL / TCSEL laser module with integrated superlens of the present application, and are also difficult to achieve with traditional VCSEL laser arrays. In addition, the superlens has a variety of control and multiplexing methods for polarization, which can realize different holographic patterns emitted in different polarization directions, etc. These functions can also be directly applied to the PCSEL / TCSEL laser module with integrated superlens of the present application. In addition to far-field emission, for near-field designs, such as focusing, near-field holography, etc., the same is true, and only different designs are required for the phase.

[0054] Figure 8 It is a simulated pattern and experimental photograph of the point cloud structure and far-field pattern realized by the semiconductor laser module of the utility model. Among them, small figures a and b are computer-simulated point cloud distributions, which are 8×16 and 48×48 points respectively. The divergence angle of a single point is about 0.3°, and the field angle is 60°. Small figure c is a holographic image of a computer-simulated numeric keyboard. Small figures d, e and f are photos of experimental results corresponding to small figures a, b and c, respectively, where the brighter points are zero-order diffraction spots, which can be solved by optimizing the design and processing. It can be seen that the PCSEL / TCSEL laser module with integrated superlens of the present application can achieve good quality dot cloud projection and holographic images.

[0055] In general, the surface-emitting semiconductor laser module realized by integrating the superlens on the surface of the PCSEL / TCSEL laser in this application has the following two advantages: First, it is small in size, which is more than an order of magnitude smaller than the traditional VCSEL light source module, which is beneficial for cost reduction and high-integration applications; second, it is powerful and can emit with arbitrary polarization and arbitrary phase in an area of ​​1mm×1mm or larger, and can efficiently complete arbitrary structured light emission, deflection, holography and other functions. Based on these advantages, the device has potential application prospects in the fields of optical sensing, laser processing, optical display, etc. In particular, the Dirac vortex topological cavity in the TCSEL laser can provide a stable mode selection mechanism, and the superlens can provide comprehensive optical modulation functions in an integrated manner. Therefore, there is reason to believe that the laser module composed of the two will be an ideal semiconductor laser light source solution with very important and broad application prospects.

[0056] An exemplary embodiment of the present invention also provides an electronic device including the above-mentioned PCSEL / TCSEL laser module with integrated superlens, which can be any electronic device using a laser light source, such as but not limited to portable electronic devices such as smart phones, tablet computers, notebook computers, smart watches, wearable electronic devices, etc., or can include vehicle-mounted electronic devices, smart home electronic devices, security electronic devices, display / projection devices, etc. In these electronic devices, the PCSEL / TCSEL laser module with integrated superlens of the present invention can be used as a light source to achieve corresponding functions, such as but not limited to face recognition, object detection, projection display, etc.

[0057] Unless the context clearly requires otherwise, throughout the specification and claims, the words "comprise", "comprising", "including", "comprising", etc. should be interpreted in an inclusive sense, rather than an exclusive or exhaustive sense. That is, the meaning is "including but not limited to". The word "connected" as generally used herein refers to two or more elements that can be directly connected or connected through one or more intermediate elements. As generally used herein, the word "connected" refers to two or more elements that can be directly connected or connected through one or more intermediate elements. In addition, when used in this application, the words "herein", "above", "below" and words of similar meanings should refer to the entirety of this application rather than to any particular part of this application. Where the context permits, the word "or" refers to a list of two or more items, which covers all of the following interpretations of the word: any item in the list, all items in the list, and any combination of items in the list.

[0058] Furthermore, unless otherwise specifically stated or understood in the context of use, conditional language used herein, such as "can," "may," "might," "could," "for example," "for example," "such as," and the like, is generally intended to convey that certain embodiments include, while other embodiments do not include, certain features, elements, and / or states. Thus, such conditional language is generally not intended to imply that one or more embodiments require features, elements, and / or states in any way, or that one or more embodiments must include logic for making decisions, with or without author input or prompting, that such features, elements, and / or states are included or will be performed in any particular embodiment.

[0059] Although certain embodiments have been described, these embodiments are presented only by way of example and are not intended to limit the scope of the present disclosure. In fact, the novel facilities, methods, and systems described herein may be embodied in various other forms; in addition, various omissions, substitutions, and changes may be made to the forms of the methods and systems described herein without departing from the spirit of the present disclosure. For example, although blocks are presented in a given arrangement, alternative embodiments may perform functions similar to different components and / or circuit topologies, and may delete, move, add, subdivide, combine, and / or modify some blocks. Each of these blocks may be implemented in a variety of different ways. Any suitable combination of the elements and actions of the various embodiments described above may be combined to provide further embodiments. The attached claims and their equivalents are intended to cover these forms or modifications that fall within the scope and spirit of the present disclosure.

[0060] The above description has been given for the purpose of illustration and description. In addition, this description is not intended to limit the embodiments of the utility model to the forms disclosed herein. Although multiple example aspects and embodiments have been discussed above, those skilled in the art will recognize certain variations, modifications, changes, additions and sub-combinations thereof.

Claims

1. A surface emitting laser module with integrated superlens, characterized in that include: A surface emitting laser, including a photonic crystal surface emitting laser or a topological cavity surface emitting laser, wherein the surface emitting laser has a light emitting surface; as well as A metalens is integrated at the light exiting surface of the surface emitting laser.

2. The surface emitting laser module according to claim 1, characterized in that: The upper surface of the top layer of the surface emitting laser is used as a light emitting surface of the surface emitting laser, The superlens includes a nano-pillar structure formed in an upper surface of the top layer.

3. The surface emitting laser module according to claim 2, characterized in that: The top layer of the surface emitting laser is a semiconductor layer, an insulating layer or a metal layer.

4. The surface emitting laser module according to claim 1, characterized in that: The upper surface of the top layer of the surface emitting laser is used as a light emitting surface of the surface emitting laser, The metalens includes a nano-pillar structure formed above the top layer.

5. The surface emitting laser module according to claim 4, characterized in that: The nano-pillar structure is formed in a super-lens layer located above the top layer of the surface emitting laser, and the super-lens layer is etched through part or all of its thickness to form the nano-pillar structure, or The nano-rod structure is formed by directly depositing, growing or epitaxially growing the nano-rod structure on the top layer of the surface emitting laser.

6. The surface emitting laser module according to claim 4, characterized in that: The nanorod structure includes semiconductor material, insulator material or metal material.

7. The surface emitting laser module according to claim 4, characterized in that: The nanorod structure includes one or more of amorphous silicon, titanium dioxide, silicon nitride, and silicon oxide.

8. The surface emitting laser module according to any one of claims 2 to 7, characterized in that: The superlens includes rectangular or elliptical nanorod structures arranged in a triangular lattice or a tetragonal lattice, and each nanorod structure has a height h, a length l, a width s, and a rotation angle θ.

9. The surface emitting laser module according to claim 8, characterized in that: One or more of the height h, length l, width s, and rotation angle θ of the nanorod structure are modulated to adjust the phase, intensity, and / or direction of the laser light emitted from the surface emitting laser module.

10. An electronic device, characterized in that A surface emitting laser module comprising any one of claims 1-9.

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