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

Abstract

The invention 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] This invention relates generally to the field of optoelectronic devices, and more particularly to a surface-emitting laser module with integrated superlens, which enables miniaturization, planarization and integration of semiconductor laser modules. Background Technology

[0002] Semiconductor lasers, due to their advantages such as small size, high efficiency, low power consumption, long lifespan, and low cost, have been widely used in many fields, including communications, medical, display, and materials processing. However, laser chips themselves are generally difficult to use alone; they need to be combined with various optical components, such as lenses, prisms, diffraction elements, and polarization elements, to form a laser module, so that the emitted 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 those of the laser chip itself. This makes it difficult to further reduce the size and price of the entire semiconductor laser module, which limits the more integrated and lower-cost applications of semiconductor laser 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 application requirements and the diffraction limit and cannot be reduced. For example, the divergence angle and far-field resolution of the beam are determined by the near-field area. Therefore, further miniaturization of laser modules can only rely on reducing the propagation length. Currently, the propagation length required for laser modules is mainly used for beam expansion and shaping of semiconductor laser spots. This is because the emission aperture of semiconductor laser chips is generally much smaller than the emission aperture required for the application. For example, the beam aperture of a dot-matrix laser module used for face recognition is about 2 millimeters, while the near-field spot of a single vertical-cavity surface-emitting laser (VCSEL) is about 10 micrometers, requiring a large propagation distance to complete beam expansion. Figure 1A This is a schematic diagram of a traditional semiconductor laser module. (Example:) Figure 1A As shown, multiple vertical-cavity surface-emitting lasers (VCSELs) 101 can be arranged in an array to provide a beam of sufficiently high power. Above the multiple VCSELs 101 are multiple optical elements, 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, a propagation length of more than 3 mm is required to provide an output spot size of approximately 2 mm × 2 mm, resulting in a large overall size of the laser module. Figure 1BThis diagram illustrates the structure of a semiconductor laser module including a newly developed metalens (also known as a metasurface) 103. A metalens is a planar optical technology that can replace traditional passive optical elements such as concave and convex lenses, reducing thickness to the wavelength order. However, this still has limited impact on reducing the size of existing laser modules because a relatively 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 output beam aperture. For example... Figure 1B As shown, when using the same array of vertical cavity surface-emitting lasers 101, in order to provide an output spot of approximately 2 mm × 2 mm, the beam propagation length for beam expansion is still about 3 mm, so the reduction in the overall size of the laser module is very limited.

[0004] Furthermore, integrating a superlens directly onto the emitting surface of a vertical-cavity surface-emitting laser (VCSEL) does not improve the size of the laser module because the emitting area of ​​a single VCSEL 101 is too small, and the emitted beam is far from meeting the requirements of practical applications, still requiring a large beam expansion distance. Therefore, the fundamental obstacle to the miniaturization of laser modules is still the lack of high-performance semiconductor lasers with near-field spot sizes that can match the required emitting aperture. Summary of the Invention

[0005] This invention provides a miniaturized module integrating a superlens surface-emitting laser (SSE) that solves one or more of the aforementioned technical problems. This invention directly integrates a superlens onto the output surface of a photonic crystal SSE or a topological cavity surface-emitting laser (PCFSE). Both photonic crystal SSEs and PCFSEs can provide large-area single-mode lasers, achieving millimeter-scale apertures and watt-scale output power. The superlens allows for the manipulation of the output light field in arbitrary degrees of freedom, such as phase, polarization, and emission angle, to achieve the desired output beam. Therefore, this invention provides a possibility for simplifying and miniaturizing laser modules. The superlens can be directly integrated into the output surface of the photonic crystal SSE or PCFSE. For example, micro / nano structures can be directly etched into the semiconductor layer of the output surface to form a superlens, or an additional superlens layer can be deposited on the output surface of the photonic crystal SSE or PCFSE, and micro / nano structures can be etched into this superlens layer to form a superlens. Alternatively, micro / nano structures can be directly deposited, grown, or epitaxially grown on the output surface of the SSE to form a superlens. This invention can provide a high-performance semiconductor laser with a near-field spot size that matches the required emission aperture, and realize the planarization and integration of the entire semiconductor laser light source, reducing its volume by more than an order of magnitude compared to existing semiconductor laser modules.

[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, the surface-emitting laser having a light-emitting surface; and a superlens integrated on the light-emitting surface of the surface-emitting laser.

[0007] In one exemplary embodiment, the upper surface of the top layer of the surface-emitting laser is used as the light-emitting surface of the surface-emitting laser, and the superlens includes a nanopillar structure formed in the upper surface of the top layer.

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

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

[0010] In one exemplary embodiment, the nanopillar structure is formed in a superlens layer located above the top layer of the surface-emitting laser, the superlens layer being etched to a portion or the entire thickness to form the nanopillar structure, or the nanopillar structure is formed by depositing, growing, or epitaxially growing nanopillar structures directly on the top layer of the surface-emitting laser.

[0011] In one exemplary embodiment, the nanopillar structure includes a semiconductor material, an insulating material, or a metallic material.

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

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

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

[0015] According to an exemplary embodiment, an electronic device is provided, including the above-described 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 taken in conjunction with the accompanying drawings. Attached Figure Description

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

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

[0019] Figure 2 This is a schematic diagram of the structure of a semiconductor laser module according to an exemplary embodiment of the present invention.

[0020] Figure 3 This is a schematic diagram of the layered structure of a semiconductor laser module according to an exemplary embodiment of the present invention.

[0021] Figure 4 This is a schematic diagram of the layered structure of a semiconductor laser module according to another exemplary embodiment of the present invention.

[0022] Figure 5 This is a schematic diagram of a nanopillar structure for forming a superlens according to an exemplary embodiment of the present invention.

[0023] Figure 6 This is a curve showing the relationship between the parameters of the nanopillar structure of the superlens and the control of the phase, wavelength, and transmittance of the emitted beam.

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

[0025] Figure 8 These are simulated patterns and experimental photographs of point cloud structures and far-field patterns realized using the semiconductor laser module of this invention. Detailed Implementation

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

[0027] Figure 2 This is a schematic diagram of the structure of a semiconductor laser module according to an exemplary embodiment of the present invention. 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). Its specific structure will be discussed in detail below. The surface-emitting laser 210 has a light-emitting surface. Figure 2The superlens 201 is integrated on the upper surface of the surface-emitting laser 210, forming its upper surface. Compared to conventional vertical-cavity surface-emitting lasers (VCSELs), photonic crystal surface-emitting lasers (PCSELs) and topological cavity surface-emitting lasers (TCSELs) can provide larger emission surfaces, such as those reaching millimeter-scale apertures. Therefore, integrating the superlens 201 onto a single surface-emitting laser 210 allows for manipulation of the emitted light field in any degree of freedom and provides a well-coherent light source. Figure 2 In some embodiments, for example, using a PCSEL or TCSEL laser with a size of approximately 1mm × 1mm, it is possible to achieve [the desired effect]. Figure 1A and Figure 1B The laser module based on the VCSEL array shown has a similar output beam aperture, while 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 source.

[0028] Figure 3 This is a schematic diagram of the layered structure of a semiconductor laser module according to an exemplary embodiment of the present invention. 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 is shown. The first semiconductor layer 214 and the second semiconductor layer 218 can have different conductivity types. For example, the first semiconductor layer 214 can be an N-type doped semiconductor layer, and the second semiconductor layer 218 can be a P-type doped semiconductor layer, or vice versa, thereby injecting N-type carriers and P-type carriers into the active layer 216, respectively. For a photonic crystal surface-emitting laser (PCSEL), the active layer 216 includes a photonic crystal layer formed therein or in its vicinity (e.g., at the upper or lower surface), which includes a semiconductor material and a spatially periodic structure formed in the semiconductor material by materials of different refractive indices, such as air, wherein the air holes are arranged spatially periodically, resulting in a periodic distribution of the optical refractive index. When light propagates therein, an energy band structure is generated, and the photon frequency in the band gap is blocked from propagating. This characteristic is used to fabricate a high-efficiency zero-threshold semiconductor laser. For a topological cavity surface-emitting laser (TCSEL), the active layer 216 similarly includes a photonic crystal layer formed therein or nearby (e.g., at the upper or lower surface). The photonic crystal supercell structure is further modulated in two independent dimensions to generate a vortex-like structural change around the cavity center of the photonic crystal cavity, thereby opening the Dirac point in the energy band of the photonic crystal supercell at its equilibrium position. 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, and will not be described in detail here. For simplicity, here... Figure 3 Only the active layer 216 is shown; a separate photonic crystal layer or topological photonic crystal layer is not shown, but it should be understood that a photonic crystal layer or 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 can be formed of a conductive metal material. To facilitate laser emission, the top electrode layer 220 can be formed in a ring shape; in other embodiments, the top electrode layer 220 can also be formed as 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 can also be formed as a single, continuous layer. Furthermore, the top electrode layer 220 can also include a very thin metal layer, allowing the laser to pass through the top electrode layer 220 for emission.

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

[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 considered as the top layer of the surface-emitting laser 210, with its upper surface serving as the light-emitting surface of the surface-emitting laser 210. The superlens 201 can be integrated into the upper surface of the second semiconductor layer 218, including a nanopillar structure formed on this surface, which will be described in detail below. In other embodiments, the top layer of the surface-emitting laser 210, i.e., the layer constituting the light-emitting surface, can be other layers, such as other semiconductor layers, or it can be an insulating protective layer, a metal layer serving as the top electrode, etc. In this case, the superlens 201 can be integrated into 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 nanopillar structure of the superlens 201. 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 its original function.

[0032] Figure 4 This is a schematic diagram of the 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 essentially 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. Repeated descriptions of these layers will be omitted here. See also... Figure 4 The semiconductor laser module also includes a top layer formed on the surface-emitting laser 210. Figure 4 The superlens layer 202 is located on the second semiconductor layer 218, wherein the nanopillar structure of the superlens 201 is formed in the upper surface of the superlens layer 202. Here, the superlens layer 202 can also be considered as part of the superlens 201. Although Figure 4The illustration shows only a portion of the thickness of the superlens layer 202 etched to form the nanopillar structure. However, in other embodiments, the entire thickness of the superlens layer 202 may be etched to form the nanopillar structure, meaning the superlens layer 202 and the nanopillar structure are the same layer. Figure 4 In the illustrated embodiment, the superlens layer 202 is deposited directly on the top layer of the surface-emitting laser 210; in other embodiments, a transparent interlayer may 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 are no gaps or openings for beam expansion as in the prior art. The superlens layer 202 may include semiconductor materials, insulating materials, or metallic 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 underlying second semiconductor layer 218 to reduce reflection, the superlens layer 202 may include silicon material, such as commonly used amorphous silicon.

[0033] Apart from Figure 4 In addition to forming a superlens layer 202 first and then etching out nanopillar structures to form a superlens 201, in other embodiments, nanopillar structures can also be deposited, grown, or epitaxially grown directly 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 openings with a desired pattern can be formed therein by photolithography or etching processes to expose the underlying light-emitting surface. Then, nanopillar structures can be deposited, grown, or epitaxially grown, and finally the sacrificial layer, such as the photoresist layer, can be removed, leaving the superlens 201 formed by the nanopillar structures.

[0034] In some exemplary embodiments, the superlens 201 can be directly formed on the top layer of the surface-emitting laser 210 or on the upper surface of the superlens layer 202 thereon via an etching process. Therefore, the step of forming the superlens 201 can be integrated into the process of forming the surface-emitting laser 210, and then the individual surface-emitting lasers 210 can be 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, the top layer of the surface-emitting laser 210 can be etched after the surface-emitting laser 210 has been manufactured and the individual surface-emitting lasers 210 have been cut out, or a superlens layer can be deposited and etched thereon to prepare the superlens 201. This invention avoids the need to attach a pre-prepared superlens to the surface-emitting laser 210 via a patch method, which is simpler in terms of process. Furthermore, patch bonding incurs additional packaging alignment costs, unnecessary waste in terms of volume and substrate material, and interface reflection problems.

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

[0036] It should be understood that throughout this application, the nanopillar structure of the superlens 201 also encompasses the formation of nanopores, which can be considered as nanopillars formed in air or a vacuum. For example, the superlens layer 202 can be formed first, and then a nanopore structure can be etched within it. The light modulation principle of the nanopore is the same as that of the nanopillar, and will not be elaborated here. Therefore, when nanopillars are mentioned in this application, they may also include nanopores.

[0037] Figure 5 This is a schematic diagram of the nanopillar structure for forming a superlens 201 according to an exemplary embodiment of the present invention. Figure 5 As shown, the superlens 201 may include rectangular nanopillar structures, but the nanopillar structures may also have other shapes, such as, but not limited to, elliptical. Multiple nanopillar structures may be arranged periodically, for example, in a two-dimensional triangular lattice (e.g., Figure 5 The nanopillars are arranged periodically in a tetragonal lattice (not shown) or a periodic arrangement with a period of P. Each nanopillar structure can have a height h, a length l, and a width s (as shown in the left figure). Figure 5 As shown in the right figure), it can also 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 can 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 nanopillar structure shown as an example, its material is amorphous silicon with a refractive index of 3.34. It is located on the second semiconductor layer 218 formed by InP. When a beam of light is incident on the nanopillar structure along the z-direction, its outgoing light field... With the incident light field The relationship can be represented as:

[0038]

[0039] Where t l and t s The transmittance coefficients of light polarized along the l-direction and along the s-direction. Let be the rotation matrix, and θ be the angle between the slow axis of the nanopillar and the predetermined x-axis direction. In the incident light field E... in Given a specific condition, by selecting parameters l, s, and θ, this nanopillar can absorb any incident light field E under near-lossless conditions.in The emitted light field E is modulated into an 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 definite incident phase and polarization. Therefore, combining the superlens 201 with the surface-emitting laser 210 can produce an outgoing beam with arbitrary phase and polarization.

[0040] Taking a topological cavity surface-emitting laser (TCSEL) as an example, the beam emitted after passing through the resonant cavity is a radially polarized vector beam. To obtain higher quality lattice clouds and clearer holograms in applications, the polarization of the beam must first be aligned. For example, modulating it into circularly polarized light requires selecting a series of combinations of side lengths l and s, such that... By selecting a rotation angle θ of the nanopillar and an angle of π / 4 between it and the polarization direction, the rectangular nanopillar acts as a quarter-wave plate, which can adjust the linearly polarized light at various positions of the vector beam to circularly polarized light. Simultaneously... The phase spanning from 0 to 2π allows circularly polarized light to have any output phase.

[0041] To ensure the absence of higher-order reflections, the arrangement period P of the nanopillar structure should be less than [value missing]. Where n InP Given the refractive index of InP, a period P of, for example, 558 nm is chosen, and the height h of the nanopillar is 1.5 μm. The length of the short side s of its rectangle ranges from 100 nm to 300 nm, and the length of the long side l ranges from 300 nm to 400 nm. Then, the exit phase at different positions is designed according to the Fourier iterative algorithm. The correspondence between the rectangle parameters, exit intensity, and exit phase is as follows: Figure 6 As shown, its transmittance is basically over 80%, exceeding the 73% transmittance of the InP substrate itself to air, which means that the surface integration of the superlens 201 also acts as an anti-reflection film.

[0042] Figure 7This is an electron micrograph of the nanopillar structure forming the superlens 201. This example shows a nanopillar structure obtained by electron beam lithography and dry etching after depositing amorphous silicon on an InP substrate (e.g., the second semiconductor layer 218). Amorphous silicon was chosen to form the superlens due to a combination of processing difficulty and modulation efficiency considerations. However, in other embodiments, other materials can be used, or the nanopillar structure can be formed directly by etching 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, which is formed as a continuous layer, the top electrode metal layer simultaneously modulates the beam and guides the current, making the current injection more uniform. However, due to the high light absorption rate of the metal, it can affect the transmittance of the emitted beam to some extent.

[0043] The semiconductor laser module of this invention has very broad application prospects. In an exemplary application scenario, when the semiconductor laser module uses a TCSEL laser, thanks to the single-mode polarization property of TCSEL and the polarization control capability of the superlens, the TCSEL laser with integrated superlens can achieve output with arbitrary polarization, which has a significant advantage compared to multimode or polarization-degenerate single-mode VCSEL lasers. For example, the TCSEL laser with integrated superlens can output both common linearly polarized Gaussian beams and circularly polarized lasers, which are generally difficult to implement 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 represented by two parameters l and m in the form of a Jones vector, i.e.

[0044]

[0045] Such beams possess unique optical properties and hold potential applications in fields such as optical communication, optical trapping, and quantum information. In fact, the beam emitted by a TCSEL laser can be considered a cylindrical vector vortex beam with l=0 and m=1. Since a superlens possesses arbitrary polarization and phase adjustment capabilities, a TCSEL laser integrating a superlens can also emit a beam with arbitrary (l,m) polarization. The simplest manipulation involves converting the hollow beam into a Gaussian mode beam (l=0, m=0) (which has the widest range of applications). This requires adjusting the polarization at each position to the same direction while maintaining the phase. At this point, the divergence angle decreases to half its original value, the laser brightness increases fourfold, and its M² factor (i.e., the laser beam quality factor) approaches 1, verifying the single-mode resonance characteristics of the TCSEL laser. The micro / nano-fabricated pattern of the superlens at this time is as follows: Figure 7 The middle pattern is shown.

[0046] For the semiconductor laser module with a superlens directly integrated on a PCSEL or TCSEL laser as described in this application, in addition to polarization control, the inventors have also researched and demonstrated its applications in structured light control, holographic patterns, and other areas. Projecting a known pattern onto a target object and obtaining the object's three-dimensional information by measuring the pattern's deformation is called structured light technology, which has been widely used in fields such as facial recognition and 3D mapping. A common type of structured light is a dense dot matrix, such as the face ID commonly used in mobile phones. Currently, structured light generation modules in consumer electronic devices typically consist of VCSEL laser arrays, lens groups, diffractive optical elements, etc. Figure 1A As shown, the laser beam is collimated and expanded by a lens group, then split by a DOE to form a lattice cloud. Depending on the specific requirements, the divergence angle of a single exit point is approximately between 0.1° and 1°. To achieve such a small divergence angle, the exit aperture size is typically around 2 mm. In this structure, various optical components require precise alignment and occupy a relatively large volume. To address this issue, Metalenz has launched the Orion product based on metasurfaces, such as... Figure 1B As shown, thanks to the arbitrary phase design capability of metasurfaces, a single metasurface layer can simultaneously perform collimation and lattice emission functions, replacing the bulky lens group and DOE in traditional modules. Although the Orion module has a simpler structure than traditional modules, its size is not significantly reduced. This is because the output aperture of the VCSEL is too small, and a large space is still needed between the VCSEL and the metasurface for the beam emitted by the VCSEL to expand and achieve a small divergence angle at a single emission point. PCSELs and TCSELs, on the other hand, inherently possess large output areas and small divergence angles, thus eliminating the need for beam expansion and collimation steps after etching the metalens, directly achieving structured light emission, such as... Figure 2 As shown below, the advantages of the integrated superlens PCSEL and TCSEL laser modules of this invention in dot projectors will be explained in detail from five aspects: volume, packaging, dot matrix quality, polarization, and wavelength.

[0047] Volume: such as Figure 2 As shown, PCSEL or TCSEL laser modules with integrated superlenses have achieved the ultimate in miniaturization. The entire module requires only a single semiconductor chip approximately 100 micrometers thick, the area of ​​which is determined by the diffraction limit required for the application. (Refer to...) Figure 1A , Figure 1B and Figure 2Compared to traditional modules, the laser module of this invention reduces its longitudinal thickness by approximately an order of magnitude and its lateral area to about a quarter of its original size. The reduction in thickness is attributed to the large-area single-mode resonant cavities of the PCSEL and TCSEL, which have an emission laser divergence angle of less than 1°, eliminating the need for laser beam expansion. Integrating the superlens onto the laser's emission surface also minimizes the thickness of the optical components. The reduction in lateral area is due to the effective beam coverage by the superlens and the high-quality beams of the PCSEL and TCSEL lasers themselves, maximizing the reduction in lateral emission area and reaching the limit of the lateral dimensions of semiconductor laser sources. This approximately 40-fold reduction in volume also results in a significant weight reduction.

[0048] Packaging: Traditional dot matrix cloud emitters consist of optical components such as VCSEL laser arrays, lens groups, and DOEs, such as... Figure 1A As shown, to ensure beam collimation and lattice uniformity, strict alignment is required between various optical components and the laser, placing high demands on packaging. However, the PCSEL / TCSEL laser module with integrated superlens of this application is a single-chip integrated module, eliminating the need to assemble different optical components and resulting in lower costs. Furthermore, traditional packaging methods such as adhesive bonding face problems such as aging of the fixing device, poor temperature stability, and interface reflection. In contrast, the PCSEL / TCSEL laser module with directly integrated superlens of this application offers a relatively longer lifespan, better stability, and higher light output efficiency.

[0049] Lattice Quality: The lattice distribution of VCSEL laser arrays inevitably contains traces of duplication and splicing, which leads to uneven distortion or overlap at the splicing edges of the point cloud image, increasing the difficulty of subsequent algorithm processing. In contrast, the lattice emitted by the PCSEL / TCSEL laser module with integrated superlens in this application is generated by a collimated beam, resulting in a more uniform lattice. A major advantage of superlenses as diffractive optical elements is their smaller modulation units, thus allowing for a larger field of view (FOV) compared to traditional DOE diffractive optical elements. For example, referring to the disclosure of invention patent CN201910430957.2, the metasurface achieves a uniform lattice emission of ±60° through interior point optimization. A larger structured light field of view means a wider detection range, which is extremely beneficial for 3D perception. This principle can also be applied to the metasurface structure of this application.

[0050] Polarization: Most VCSEL laser arrays currently in use are non-polarization-selective multimode VCSEL lasers, and their emitted far-field light has uncertain polarization. In contrast, PCSEL / TCSEL lasers have definite single-mode polarization states, and therefore, the far-field of PCSEL / TCSEL laser modules with integrated superlenses also has definite polarization. If linearly polarized or circularly polarized light is emitted in a specific direction, stray light of other polarizations can be filtered out at the receiving end, or the polarization information of the object being detected can be obtained.

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

[0052] Structured light lattice is just one representative application of the PCSEL / TCSEL laser module with integrated superlens described in this application. Besides this, it can achieve a variety of far-field functions, including light deflection, uniform planar light emission, and holographic imaging. Enabling direct oblique emission of the laser beam allows the array of the PCSEL / TCSEL laser module with integrated superlens to achieve functions such as all-solid-state lidar. Its phase design is also very simple; when the deflection angle is... At that time, the phase distribution on the laser surface is... Where x is its horizontal position, y is its vertical position, and λ is the wavelength.

[0053] The PCSEL / TCSEL laser module with integrated superlens of this application can also efficiently realize various holographic images. Achieving a clear holographic pattern requires two things: a sufficiently large coherent light area and precise phase control. Both of these are possessed by the PCSEL / TCSEL laser module with integrated superlens of this application, and are difficult to achieve with traditional VCSEL laser arrays. Furthermore, superlenses offer various methods for controlling and multiplexing polarization, enabling the emission of different holographic patterns with different polarization directions. These functions can also be directly applied to the PCSEL / TCSEL laser module with integrated superlens of this application. Besides far-field emission, the same principle applies to near-field designs, such as focusing and near-field holography; only different phase designs are needed.

[0054] Figure 8 These are simulated patterns and experimental photographs of point cloud structures and far-field patterns realized using the semiconductor laser module of this invention. In the figures, insets a and b are computer-simulated point cloud distributions, with 8×16 and 48×48 points respectively, a divergence angle of approximately 0.3° for a single point, and a field of view of 60°. Inset c is a computer-simulated holographic image of a digital keyboard. Insets d, e, and f are experimental result photographs corresponding to insets a, b, and c, where the brighter points are zero-order diffraction spots, which can be addressed through optimized design and fabrication. It can be seen that the PCSEL / TCSEL laser module with integrated superlens of this application can achieve high-quality point cloud projection and holographic images.

[0055] In summary, the surface-emitting semiconductor laser module implemented by integrating a superlens onto the surface of a PCSEL / TCSEL laser has two main advantages: First, it is small in size, more than an order of magnitude smaller than traditional VCSEL light source modules, which is beneficial for cost reduction and high integration applications. Second, it is powerful in function, capable of emitting light with arbitrary polarization and phase in an area of ​​1mm×1mm or larger, thus efficiently performing functions such as arbitrary structured light emission, deflection, and holography. Based on these advantages, this device has potential applications in optical sensing, laser processing, and optical display. In particular, the Dirac vortex topology 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, it is reasonable to believe that the laser module formed by combining these 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 aforementioned PCSEL / TCSEL laser module with integrated superlens. This electronic device can be any electronic device using a laser light source, such as, but not limited to, portable electronic devices like smartphones, tablets, laptops, smartwatches, wearable electronic devices, etc., or it can include in-vehicle 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 explicitly requires otherwise, throughout the specification and claims, the words “comprising,” “including,” “comprise,” “including,” etc., shall be interpreted in an inclusive sense, rather than an exclusive or exhaustive sense. That is, they mean “including but not limited to.” The term “connection” as commonly used herein refers to two or more elements that can be directly connected or connected via one or more intermediate elements. Furthermore, when used in this application, the terms “this,” “above,” “below,” and similar terms shall refer to the entire application and not any particular part thereof. Where the context permits, the term “or” refers to a list of two or more items, encompassing all of the following interpretations: 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 otherwise understood in the context in which they are used, the conditional language used herein, such as “can,” “may,” “possibly,” “can,” “for example,” “likely,” “such as,” etc., is generally intended to express that certain embodiments include certain features, elements, and / or states, while other embodiments do not. Therefore, such conditional language is not generally 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 a decision, with or without author input or prompts, that determines whether such features, elements, and / or states are included in or will be performed in any particular embodiment.

[0059] While certain embodiments have been described, these embodiments are presented by way of example only and are not intended to limit the scope of this disclosure. In fact, the novel facilities, methods, and systems described herein can be embodied in a variety of other forms; furthermore, various omissions, substitutions, and changes can be made to the form of the methods and systems described herein without departing from the spirit of this 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 some blocks may be deleted, moved, added, subdivided, combined, and / or modified. Each of these blocks can be implemented in a variety of different ways. Any suitable combination of elements and actions of the various embodiments described above can be combined to provide further embodiments. The appended claims and their equivalents are intended to cover these forms or modifications that fall within the scope and spirit of this disclosure.

[0060] The above description has been given for purposes of illustration and description. Furthermore, this description is not intended to limit the embodiments of the invention to the forms disclosed herein. Although numerous exemplary aspects and embodiments have been discussed above, those skilled in the art will recognize certain variations, modifications, alterations, additions, and sub-combinations therein.

Claims

1. A surface-emitting laser module with integrated superlens, 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; as well as A superlens integrated on the light-emitting surface of the surface-emitting laser.

2. The surface-emitting laser module as described in claim 1, wherein, The upper surface of the top layer of the surface-emitting laser is used as the light-emitting surface of the surface-emitting laser. The superlens includes a nanopillar structure formed in the upper surface of the top layer.

3. The surface-emitting laser module as described in claim 2, wherein, 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 as described in claim 1, wherein, The upper surface of the top layer of the surface-emitting laser is used as the light-emitting surface of the surface-emitting laser. The superlens includes a nanopillar structure formed above the top layer.

5. The surface-emitting laser module as described in claim 4, wherein, The nanopillar structure is formed in a superlens layer located above the top layer of the surface-emitting laser, the superlens layer being etched partially or entirely to form the nanopillar structure, or The nanopillar structure is formed by depositing, growing, or epitaxially growing nanopillar structures directly on the top layer of the surface-emitting laser.

6. The surface-emitting laser module as described in claim 4, wherein, The nanopillar structure includes semiconductor materials, insulating materials, or metallic materials.

7. The surface-emitting laser module as described in claim 4, wherein, The nanopillar 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 2-7, wherein, The superlens comprises rectangular or elliptical nanopillar structures arranged in a triangular or tetragonal lattice, and each nanopillar structure has a height h, a length l, a width s, and a rotation angle θ.

9. The surface-emitting laser module as described in claim 8, wherein, One or more of the height h, length l, width s, and rotation angle θ of the nanopillar structure are modulated to adjust the phase, intensity, and / or direction of the laser emitted from the surface-emitting laser module.

10. An electronic device comprising a surface-emitting laser module as described in any one of claims 1-9.

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