Modulated angular energy distribution metasurface construction method, system, chip and preparation method

Abstract

The present invention discloses a metasurface construction method, system and chip preparation method for modulating angular energy distribution, including: constructing a change curve diagram of the phase and transmittance of the target metasurface with the radius or deflection angle of the target nanounit according to the target wavelength, the target VCSEL chip structure, the target chip substrate material, the target nanostructure material and the target nanounit structure through the time domain finite difference method; obtaining the lattice constant that maintains the target transmittance within the target range according to the change curve diagram; dividing the target metasurface according to the lattice constant; obtaining the corresponding target phase distribution according to the target angular energy distribution corresponding to the unit cell in each metasurface unit cell set; searching the change curve diagram according to each target phase distribution to construct the corresponding metasurface target nanounit set; constructing the target metasurface according to the target nanounit set and the metasurface unit cell set. Through FDTD simulation, a metasurface structure that can achieve the target angular energy distribution is constructed.

Description

Technical Field

[0001] The present invention relates to the field of optical chips, and in particular to a method and system for constructing a metasurface with modulated angular energy distribution, and a method for preparing a chip. Background Art

[0002] Traditional mainstream linear light sources include light source chips, beam shaping lenses, chip packaging substrates, and fixed structures. During production, the light source chip needs to be fixed on the packaging substrate, and then the lenses required for light source shaping are connected and fixed to the packaging substrate and the fixed structure one by one. The entire process is complex and time-consuming, and requires the participation of multiple different automated equipment. Metasurface is a two-dimensional surface material structure composed of nanostructures arranged at subwavelength intervals, and its target nanounit is composed of metal or all-dielectric materials. It uses the optical response of the unit structure to change the local light wave distribution on a subwavelength scale. Light passing through the metasurface can produce phase mutations, and this property can be used to control the amplitude, phase, and polarization state of the light field. Metasurfaces have the advantages of miniaturized planar components and have the prospect of replacing traditional refractive optical components. However, there is a lack of corresponding technical solutions for how to achieve the required energy distribution by constructing a metasurface. Summary of the invention

[0003] In order to solve the technical problem that there is a lack of technical solutions for constructing a metasurface to achieve the required energy distribution in the prior art, the present invention provides a metasurface construction method, system and chip preparation method for modulating angular energy distribution. The specific technical solutions are as follows:

[0004] On the one hand, a method for constructing a metasurface with modulated angular energy distribution is provided, comprising:

[0005] Obtaining a target wavelength of a target VCSEL chip, a target VCSEL chip structure, a target chip substrate material, a target nanounit structural material, and a target nanounit structure; the target nanounit is disposed on a target metasurface;

[0006] According to the target wavelength, the target VCSEL chip structure, the target chip substrate material, the target nanostructure material, and the target nanounit structure, a curve diagram of the phase and transmittance of the target metasurface changing with the radius or deflection angle of the target nanounit is constructed by a time-domain finite difference method;

[0007] According to the change curve, obtaining a lattice constant that maintains a target transmittance within a target range;

[0008] Dividing the target metasurface according to the lattice constant to obtain a metasurface unit cell set; a target energy distribution acquisition module, according to the target angular energy distribution corresponding to each unit cell in the metasurface unit cell set, to obtain a corresponding target phase distribution;

[0009] Searching the variation curve diagram according to the target phase distribution corresponding to the supersurface lattice in each of the supersurface unit cell sets to construct a corresponding supersurface target nanounit set;

[0010] The target supersurface is constructed according to the target nanounit set and the supersurface unit cell set.

[0011] Preferably, the target phase distribution satisfies Among them, φ is the phase difference, f is the equivalent focal length of the field of view angle of the VCSEL chip using the target metasurface, x is the long axis direction coordinate of the unit cell at the field of view angle, y is the short axis direction coordinate of the unit cell at the field of view angle, and λ is the target wavelength.

[0012] Preferably, the target phase distribution satisfies Among them, φ is the phase difference, f is the equivalent focal length of the field of view angle of the VCSEL chip using the target metasurface, x is the long axis direction coordinate of the unit cell at the field of view angle, y is the short axis direction coordinate of the unit cell at the field of view angle, and λ is the target wavelength.

[0013] Preferably, the target nanometer unit structure is a cylinder or a cube; and the height of the target nanometer unit is smaller than the target wavelength.

[0014] Preferably, after being modulated by the target metasurface, the light of the target VCSEL chip is modulated into a line light source.

[0015] In another aspect, a metasurface construction system for modulating angular energy distribution is provided, comprising:

[0016] A target parameter acquisition module is used to acquire a target wavelength of a target VCSEL chip, a target VCSEL chip structure, a target chip substrate material, a target nano-unit structural material, and a target nano-unit structure of a target nano-unit; the target nano-unit is arranged on a target metasurface;

[0017] A phase relationship acquisition module is used to construct a curve diagram of the phase and transmittance of the target metasurface as a function of the radius or deflection angle of the target nanounit by using a finite difference time domain method according to the target wavelength, the target VCSEL chip structure, the target chip substrate material, the target nanostructure material, and the target nanounit structure;

[0018] A lattice constant generating module, used for obtaining a lattice constant that maintains a target transmittance within a target range according to the change curve diagram;

[0019] A metasurface unit cell set acquisition module, used to divide the target metasurface according to the lattice constant to acquire a metasurface unit cell set; a target energy distribution acquisition module, used to acquire a corresponding target phase distribution according to a target angular energy distribution corresponding to each unit cell in the metasurface unit cell set;

[0020] A target nanometer unit set acquisition module is used to find the change curve diagram according to the target phase distribution corresponding to the supersurface lattice in each of the supersurface unit cell sets, so as to construct a corresponding supersurface target nanometer unit set;

[0021] The target supersurface construction module is used to construct the target supersurface according to the target nanounit set and the supersurface unit cell set.

[0022] Preferably, the target phase distribution satisfies Among them, φ is the phase difference, f is the equivalent focal length of the field of view angle of the VCSEL chip using the target metasurface, x is the long axis direction coordinate of the unit cell at the field of view angle, y is the short axis direction coordinate of the unit cell at the field of view angle, and λ is the target wavelength.

[0023] Preferably, the target phase distribution satisfies Among them, φ is the phase difference, f is the equivalent focal length of the field of view angle of the VCSEL chip using the target metasurface, x is the long axis direction coordinate of the unit cell at the field of view angle, y is the short axis direction coordinate of the unit cell at the field of view angle, and λ is the target wavelength.

[0024] Preferably, the target nanometer unit structure is a cylinder or a cube, and the height of the target nanometer unit is smaller than the target wavelength.

[0025] In another aspect, a method for preparing a chip for modulating angular energy distribution is provided, comprising:

[0026] Etching is performed on the VCSEL epitaxial wafer to obtain a mesa structure;

[0027] performing wet oxidation on the mesa structure to form oxidation holes;

[0028] growing SiO2 on the mesa structure;

[0029] Sequentially evaporating the P and N surface electrodes of the mesa structure by electron beam evaporation;

[0030] Performing high temperature annealing on the mesa structure to form an ohmic contact to form a VCSEL laser;

[0031] A layer of super-surface dielectric material film is grown on the emission hole of the VCSEL laser; the material of the super-surface dielectric material film is single crystal silicon.

[0032] The metasurface dielectric film is processed into a metasurface structure array capable of forming a linear outgoing laser beam by an etching process on the VCSEL laser, and the metasurface structure is constructed according to the metasurface construction method for modulating angular energy distribution.

[0033] A chip for modulating angular energy distribution comprises an N electrode, a GaAs substrate, a buffer layer, an NDBR layer, a quantum well active layer, an oxide layer, a PDBR layer, a contact layer, and a P electrode arranged in sequence; wherein the N electrode is placed under the GaAs substrate and in contact with the GaAs substrate, and the P electrode is placed on the contact layer and in contact with the contact layer; the NDBR layer is composed of a distributed Bragg reflector made of AlGaAs with different components and adopts n-type doping; the PDBR layer is composed of a distributed Bragg reflector made of AlGaAs with different components and adopts p-type doping, and is characterized in that:

[0034] It also includes a super surface structure, which is constructed according to the super surface construction method for modulating angular energy distribution.

[0035] The present invention includes at least one of the following technical effects: This embodiment constructs a metasurface structure that can achieve target angular energy distribution through FDTD simulation, and integrates the phase structure metasurface with the vertical cavity surface emitting laser (VCSEL). The light source will become a chip-level product and no longer needs to be produced in the form of an integrated module. Compared with the existing technical solutions, it can greatly simplify the production process and size structure of the light source module. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0037] Figure 1 A schematic diagram of a process of constructing a metasurface for modulating angular energy distribution according to the present invention;

[0038] Figure 2 Schematic diagram of the structure of the VCSEL chip involved in the present invention;

[0039] Figure 3 A schematic diagram of a super surface of a VCSEL chip involved in the present invention;

[0040] Figure 4A schematic diagram showing the changes in transmittance and phase of a VCSEL chip with a designed wavelength of 940 nm, a substrate material of SiO2, a nanostructure material of single crystal silicon Si, and a cylindrical nanostructure as a function of the radius or deflection angle of a target nanounit;

[0041] Figure 5 It is a schematic diagram of the relationship between phase and angular energy distribution of the present invention;

[0042] Figure 6 This is a schematic diagram of the line laser effect of the present invention;

[0043] Figure 7 The figure is a schematic flow chart of a method for preparing a chip for modulating angular energy distribution according to the present invention;

[0044] Figure 8 Schematic diagram of structural changes in the manufacturing process of the chip preparation method for modulating angular energy distribution of the present invention. DETAILED DESCRIPTION

[0045] In the following description, specific details such as specific system structures, technologies, etc. are provided for the purpose of illustration rather than limitation, so as to provide a thorough understanding of the embodiments of the present application. However, it should be clear to those skilled in the art that the present application may also be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted to prevent unnecessary details from obstructing the description of the present application.

[0046] It should be understood that when used in this specification and the appended claims, the term "comprising" indicates the presence of the described features, integers, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or collections.

[0047] In order to simplify the drawings, only the parts related to the present invention are schematically shown in each figure, and they do not represent the actual structure of the product. In addition, in order to simplify the drawings and facilitate understanding, in some figures, only one of the parts with the same structure or function is schematically drawn or marked. In this article, "one" not only means "only one", but also means "more than one".

[0048] It should be further understood that the term “and / or” used in the specification and appended claims refers to any combination and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0049] In addition, in the description of the present application, the terms "first", "second", etc. are only used to distinguish the description and cannot be understood as indicating or implying relative importance.

[0050] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the specific implementation methods of the present invention will be described below with reference to the accompanying drawings. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings and other implementation methods can be obtained based on these drawings without creative work.

[0051] Embodiment 1:

[0052] This embodiment provides a method for constructing a metasurface that modulates angular energy distribution, such as Figure 1 As shown, including:

[0053] S7-1: Acquire a target wavelength of a target VCSEL chip, a target VCSEL chip structure, a target chip substrate material, a target nanocell structural material, and a target nanocell structure of a target nanocell; the target nanocell is disposed on a target metasurface;

[0054] S7-2: According to the target wavelength, the target VCSEL chip structure, the target chip substrate material, the target nanostructure material, and the target nanounit structure, a curve diagram of the phase and transmittance of the target metasurface changing with the radius of the target nanounit is constructed by using a finite difference time domain method;

[0055] S7-3: according to the change curve, obtaining a lattice constant for maintaining a target transmittance within a target range;

[0056] S7-4: Dividing the target hypersurface according to the lattice constant, and obtaining a hypersurface unit cell set;

[0057] S7-5: acquiring a corresponding target phase distribution according to a target angular energy distribution corresponding to each unit cell in the metasurface unit cell set;

[0058] S7-6: searching the change curve diagram according to the target phase distribution corresponding to the supersurface lattice in each of the supersurface unit cell sets to construct a corresponding supersurface target nanounit set;

[0059] S7-7: Construct the target supersurface according to the target nanounit set and the supersurface unit cell set.

[0060] Traditional mainstream linear light sources include light source chips, beam shaping lenses, chip packaging substrates, and fixed structures. During production, the light source chip needs to be fixed on the packaging substrate, and then the lenses required for light source shaping are connected and fixed to the packaging substrate and the fixed structure one by one. The entire process is complex and time-consuming, and requires the participation of multiple different automated equipment. Metasurfaces are two-dimensional surface material structures arranged in nanostructures at subwavelength intervals, and their target nanounits are composed of metal or all-dielectric materials. It uses the optical response of the unit structure to change the local light wave distribution on a subwavelength scale. Light passing through the metasurface can produce phase mutations, and this property can be used to control the amplitude, phase, and polarization state of the light field. Metasurfaces have the advantages of miniaturized planar elements and have the prospect of replacing traditional refractive optical elements.

[0061] By integrating the phase structure metasurface with the vertical cavity surface emitting laser (VCSEL), the line laser light source will become a chip-level product and no longer need to be produced in the form of an integrated module. Compared with the existing technical solutions, it can greatly simplify the production process and size structure of the line structure light source module. However, in the traditional technical solutions, the application of metasurfaces is mostly applied to changes in the wavelength of light itself, but does not involve changes in the energy distribution of the light beam. Therefore, in this embodiment, a method for constructing a metasurface that can modulate the angular energy distribution is proposed to construct a metasurface that can meet the target angular energy requirements.

[0062] Specifically, firstly, the target wavelength of the target VCSEL chip, the target VCSEL chip structure, the target chip substrate material, the target nano-unit structural material and the target nano-unit structure of the target nano-unit are obtained.

[0063] Generally speaking, if Figure 2 , 3 As shown in FIG. 1 , the structure of the target VCSEL chip is as follows: from bottom to top, N electrode, GaAs substrate, buffer layer, NDBR (distributed Bragg reflector composed of AlGaAs with different components, n-type doping), quantum well active layer (MQW), oxide layer (oxide), PDBR (distributed Bragg reflector composed of AlGaAs with different components, p-type doping), contact layer, and P electrode. The N electrode is placed under the GaAs substrate and contacts the GaAs substrate, and the P electrode is placed on the contact layer and contacts the contact layer. The silicon dioxide passivation layer covers the part of the device (except the electrode) that contacts the air.

[0064] When the device is in operation, current is injected from the P-side annular electrode and flows out from the N-side electrode. The holes injected from the P electrode and the electrons injected from the N electrode reach the quantum well active layer area and undergo stimulated recombination in the quantum well active layer to generate light. The light oscillates between the NDBR and the PDBR and finally exits from the PDBR (lower reflectivity) side.

[0065] In the specific setting of the metasurface, the metasurface layer is made in the light-emitting hole (upper distributed Bragg reflector structure), and the spatial angular energy distribution of a multi-modal mixed light beam will become a specified line laser beam after passing through the metasurface layer. At the same time, the metasurface layer can also be set on a GaAs substrate. When the metasurface layer is set on a GaAs substrate, the NDBR reflectivity in the structure of the VCSEL decreases, and the PDBR reflectivity increases. Finally, the PDBR reflectivity is close to 100%, and the NDBR reflectivity is lower than the PDBR. At this time, the light generated by the quantum well active layer of the device in the working state will oscillate between the NDBR and the PDBR, and finally emit on the NDBR (lower reflectivity) side.

[0066] Generally speaking, the metasurface layer is made in the light-emitting hole. The metasurface is close to the light-emitting surface, and an additional substrate layer is required to achieve the technical effect. Therefore, the metasurface layer is generally set on a GaAs substrate to improve efficiency and save costs.

[0067] Then, after obtaining the change curve of the phase and transmittance of the corresponding target supersurface with the radius or deflection angle of the target nanounit, the lattice units are divided according to the change curve, and the phase distribution corresponding to the angular energy distribution corresponding to the position of each unit cell is determined to determine the phase distribution to be achieved by the nanounit at that location, and the radius of the nanounit is determined according to the change curve, thereby constructing the entire supersurface structure.

[0068] This embodiment uses FDTD simulation to construct a metasurface structure that can achieve the target angular energy distribution, and integrates the phase structure metasurface with the vertical cavity surface emitting laser (VCSEL). The light source will become a chip-level product and no longer needs to be produced in the form of an integrated module. Compared with the existing technical solutions, it can greatly simplify the production process and size structure of the light source module.

[0069] Preferably, the target nanometer unit structure is a cylinder or a cube; and the height of the target nanometer unit is smaller than the target wavelength.

[0070] In terms of the structure and material of the specific target nanounit, the metasurface layer can be etched into nanocolumns on the DBR layer as the target nanounit, or can be etched into small holes on the metasurface dielectric material as the target nanounit. The target nanounit is generally set to be a cube or a cylinder, and its height is at the subwavelength level, that is, less than the wavelength of the VCSEL output laser. In terms of the shape of the specific target nanounit, if the design application does not consider the control of the polarization state of the output light, a cylinder can be selected as the target nanounit.

[0071] The nanostructure layout of the super surface layer can be fixed pitch with variable size or fixed size with variable pitch. Generally speaking, fixed pitch with variable size is adopted for the convenience of production and calculation. The height of all target nano units is consistent, and the constituent materials can be metal or all-dielectric materials, such as single crystal silicon.

[0072] After obtaining the target wavelength of the target VCSEL chip, the target VCSEL chip structure, the target chip substrate material, the target nanounit structure material, and the target nanounit structure, a relationship diagram between each lattice constant, the radius of the target nanounit structure, and the transmittance can be constructed, where the lattice constant refers to the side length of each unit cell on the metasurface, and each target nanounit structure is set in the center of the corresponding unit cell, such as Figure 3 As shown. According to the relationship diagram, the lattice constant that can maintain a high transmittance within the phase coverage range of 2π can be obtained. In general, the lattice constant with a transmittance of more than 0.85 is selected to divide the metasurface. Then, taking the unit cell as the unit, the target energy distribution corresponding to each unit cell is obtained, and the required target phase distribution is obtained according to the energy distribution. When the phase distribution is known, the size of the required target nanounit structure can be obtained by reversely searching the aforementioned relationship table, and then the target metasurface is constructed according to the target nanounit set and the metasurface unit cell set composed of each target nanounit, so as to obtain the required metasurface structure.

[0073] Preferably, the target phase distribution satisfies Among them, φ is the phase difference, f is the equivalent focal length of the field of view angle of the VCSEL chip using the target metasurface, x is the long axis direction coordinate of the unit cell at the field of view angle, y is the short axis direction coordinate of the unit cell at the field of view angle, and λ is the target wavelength.

[0074] Or: The target phase distribution satisfies Among them, φ is the phase difference, f is the equivalent focal length of the field of view angle of the VCSEL chip using the target metasurface, x is the long axis direction coordinate of the unit cell at the field of view angle, y is the short axis direction coordinate of the unit cell at the field of view angle, and λ is the target wavelength.

[0075] like Figure 6 As shown, in the specific modulation process, since the energy distribution modulated to the target is essentially to modulate the field of view, that is, FOV, of the target VCSEL chip. More specifically, when the long axis of the field of view needs to be modulated, Formula 1 is used:

[0076]

[0077] If the short axis of the field of view needs to be modulated, use Formula 2:

[0078]

[0079] Preferably, after being modulated by the target metasurface, the light of the target VCSEL chip is modulated into a line light source.

[0080] Generally speaking, after the metasurface is modulated, a linear light source should be obtained. Common specifications include 120×1 and 80×2. Under this light source, the divergence angle of the light source in the short axis direction is negligible relative to the long axis. In practice, it is often only necessary to control the divergence angle of the light source in the long axis direction. Therefore, more phase control is often performed on the long axis, and the short axis direction is almost unchanged. That is, the corresponding metasurface is generally constructed through formula 1, and then the corresponding emission angle is generated.

[0081] Taking a VCSEL chip with a design wavelength of 940nm, a substrate material of SiO2, a nanostructure material of single crystal silicon Si, and a cylindrical nanostructure as an example, in the design process, because different lattice constants correspond to different change curves, multiple different lattice constants are set, and the phase and transmittance of the target metasurface are constructed with the radius of the target nanounit by the time-domain finite difference method, and the lattice constant whose transmittance is always greater than 0.85 in the range of 0 to 2π is selected as the lattice constant of the target metasurface, such as Figure 4 As shown, the lattice constant is then used to discretize and uniformly set the target nano-units of the metasurface, and the corresponding change curve is selected as a reference for the radius of the cylinder in each subsequent unit cell. Then, according to the angular energy corresponding to each unit cell, the corresponding phase distribution is obtained, as shown in Figure 5As shown, based on the phase distribution, through the aforementioned formula 1, when the equivalent focal length, the position of the unit cell, and the wavelength are known, the phase difference that needs to be supplemented by the unit cell at that location can be easily calculated, and by referring to the change curve, through the relationship between the phase distribution and the cylindrical target nanounit, the radius of the required target nanounit can be deduced, and then the required nano-supersurface structure can be obtained.

[0082] Embodiment 2:

[0083] This embodiment provides a metasurface construction system for modulating angular energy distribution, including:

[0084] A target parameter acquisition module is used to acquire a target wavelength of a target VCSEL chip, a target VCSEL chip structure, a target chip substrate material, a target nano-unit structural material, and a target nano-unit structure of a target nano-unit; the target nano-unit is arranged on a target metasurface;

[0085] A phase relationship acquisition module, used to construct a curve diagram of the phase and transmittance of the target metasurface versus the radius of the target nanounit by using a finite difference time domain method according to the target wavelength, the target VCSEL chip structure, the target chip substrate material, the target nanostructure material, and the target nanounit structure;

[0086] A lattice constant generating module, used for obtaining a lattice constant that maintains a target transmittance within a target range according to the change curve diagram;

[0087] A supersurface unit cell set acquisition module, used for dividing the target supersurface according to the lattice constant to acquire a supersurface unit cell set;

[0088] A target energy distribution acquisition module, which acquires a corresponding target phase distribution according to a target angular energy distribution corresponding to each unit cell in the metasurface unit cell set;

[0089] A target nanometer unit set acquisition module is used to find the change curve diagram according to the target phase distribution corresponding to the supersurface lattice in each of the supersurface unit cell sets, so as to construct a corresponding supersurface target nanometer unit set;

[0090] The target supersurface construction module is used to construct the target supersurface according to the target nanounit set and the supersurface unit cell set.

[0091] Traditional mainstream linear light sources include light source chips, beam shaping lenses, chip packaging substrates, and fixed structures. During production, the light source chip needs to be fixed on the packaging substrate, and then the lenses required for light source shaping are connected and fixed to the packaging substrate and the fixed structure one by one. The entire process is complex and time-consuming, and requires the participation of multiple different automated equipment. Metasurfaces are two-dimensional surface material structures arranged in nanostructures at subwavelength intervals, and their target nanounits are composed of metal or all-dielectric materials. It uses the optical response of the unit structure to change the local light wave distribution on a subwavelength scale. Light passing through the metasurface can produce phase mutations, and this property can be used to control the amplitude, phase, and polarization state of the light field. Metasurfaces have the advantages of miniaturized planar elements and have the prospect of replacing traditional refractive optical elements.

[0092] By integrating a phase structure metasurface with a vertical cavity surface emitting laser (VCSEL), a linear laser light source will become a chip-level product and no longer need to be produced in the form of an integrated module. Compared with the prior art solutions, it can greatly simplify the production process and size structure of the linear light source module. However, in traditional technical solutions, the application of metasurfaces is mostly applied to changes in the wavelength of light itself, but does not involve changes in the energy distribution of the light beam. Therefore, in this embodiment, a method for constructing a metasurface that can modulate angular energy distribution is proposed to construct a metasurface that can meet the target angular energy requirements.

[0093] Specifically, firstly, the target wavelength of the target VCSEL chip, the target VCSEL chip structure, the target chip substrate material, the target nano-unit structural material and the target nano-unit structure of the target nano-unit are obtained.

[0094] Generally speaking, if Figure 2 , 3 As shown in FIG. 1 , the structure of the target VCSEL chip is as follows: from bottom to top, N electrode, GaAs substrate, buffer layer, NDBR (distributed Bragg reflector composed of AlGaAs with different components, n-type doping), quantum well active layer (MQW), oxide layer (oxide), PDBR (distributed Bragg reflector composed of AlGaAs with different components, p-type doping), contact layer, and P electrode. The N electrode is placed under the GaAs substrate and contacts the GaAs substrate, and the P electrode is placed on the contact layer and contacts the contact layer. The silicon dioxide passivation layer covers the part of the device (except the electrode) that contacts the air.

[0095] When the device is in operation, current is injected from the P-side annular electrode and flows out from the N-side electrode. The holes injected from the P electrode and the electrons injected from the N electrode reach the quantum well active layer area and undergo stimulated recombination in the quantum well active layer to generate light. The light oscillates between the NDBR and the PDBR and finally exits from the PDBR (lower reflectivity) side.

[0096] In the specific setting of the metasurface, the metasurface layer is made in the light-emitting hole (upper distributed Bragg reflector structure), and the spatial angular energy distribution of a multi-modal mixed light beam will become a specified line laser beam after passing through the metasurface layer. At the same time, the metasurface layer can also be set on a GaAs substrate. When the metasurface layer is set on a GaAs substrate, the NDBR reflectivity in the structure of the VCSEL decreases, and the PDBR reflectivity increases. Finally, the PDBR reflectivity is close to 100%, and the NDBR reflectivity is lower than the PDBR. At this time, the light generated by the quantum well active layer of the device in the working state will oscillate between the NDBR and the PDBR, and finally emit on the NDBR (lower reflectivity) side.

[0097] Generally speaking, since the metasurface layer is made in the light-emitting hole, the metasurface is far away from the light-emitting area, and an additional substrate layer is required to achieve the technical effect. Therefore, the metasurface layer is generally set on a GaAs substrate to improve efficiency and save costs.

[0098] Then, after obtaining the change curve of the phase and transmittance of the corresponding target supersurface with the radius of the target nanounit, the lattice units are divided according to the change curve, and the phase distribution corresponding to the angular energy distribution corresponding to the position of each unit cell is determined to determine the phase distribution to be achieved by the nanounit at that location, and the radius of the nanounit is determined according to the change curve, thereby constructing the entire supersurface structure.

[0099] This embodiment uses FDTD simulation to construct a metasurface structure that can achieve the target angular energy distribution, and integrates the phase structure metasurface with the vertical cavity surface emitting laser (VCSEL). The light source will become a chip-level product and no longer needs to be produced in the form of an integrated module. Compared with the existing technical solutions, it can greatly simplify the production process and size structure of the light source module.

[0100] Preferably, the target nanometer unit structure is a cylinder or a cube; and the height of the target nanometer unit is smaller than the target wavelength.

[0101] In terms of the structure and material of the specific target nano-unit, the metasurface layer can be etched into nano-columns on the DBR layer as the target nano-unit, or can be etched into small holes on the metasurface dielectric material as the target nano-unit. The target nano-unit is generally set to be a cube or a cylinder, and its height is at the sub-wavelength level, that is, less than the wavelength of the VCSEL output laser. In terms of the shape of the specific target nano-unit, if the design application does not consider the control of the polarization state of the output light, a cylinder can be selected as the target nano-unit.

[0102] The nanostructure layout of the super surface layer can be fixed pitch with variable size or fixed size with variable pitch. Generally speaking, fixed pitch with variable size is adopted for the convenience of production and calculation. The height of all target nano units is consistent, and the constituent materials can be metal or all-dielectric materials, such as single crystal silicon.

[0103] After obtaining the target wavelength of the target VCSEL chip, the target VCSEL chip structure, the target chip substrate material, the target nanounit structure material, and the target nanounit structure, a relationship diagram between each lattice constant, the radius of the target nanounit structure, and the transmittance can be constructed, where the lattice constant refers to the side length of each unit cell on the metasurface, and each target nanounit structure is set in the center of the corresponding unit cell, such as Figure 3 As shown. According to the relationship diagram, the lattice constant that can maintain a high transmittance within the phase coverage range of 2π can be obtained. In general, the lattice constant with a transmittance of more than 0.85 is selected to divide the metasurface. Then, taking the unit cell as the unit, the target energy distribution corresponding to each unit cell is obtained, and the required target phase distribution is obtained according to the energy distribution. When the phase distribution is known, the size of the required target nanounit structure can be obtained by reversely searching the aforementioned relationship table, and then the target metasurface is constructed according to the target nanounit set and the metasurface unit cell set composed of each target nanounit, so as to obtain the required metasurface structure.

[0104] Preferably, the target phase distribution satisfies Among them, φ is the phase difference, f is the equivalent focal length of the field of view angle of the VCSEL chip using the target metasurface, x is the long axis direction coordinate of the unit cell at the field of view angle, y is the short axis direction coordinate of the unit cell at the field of view angle, and λ is the target wavelength.

[0105] Or: The target phase distribution satisfies Among them, φ is the phase difference, f is the equivalent focal length of the field of view angle of the VCSEL chip using the target metasurface, x is the long axis direction coordinate of the unit cell at the field of view angle, y is the short axis direction coordinate of the unit cell at the field of view angle, and λ is the target wavelength.

[0106] like Figure 6 As shown, in the specific modulation process, since the energy distribution modulated to the target is essentially to modulate the field of view, that is, FOV, of the target VCSEL chip. More specifically, when the long axis of the field of view needs to be modulated, Formula 1 is used:

[0107]

[0108] If the short axis of the field of view needs to be modulated, use Formula 2:

[0109]

[0110] Preferably, after being modulated by the target metasurface, the light of the target VCSEL chip is modulated into a line light source.

[0111] Generally speaking, after the metasurface is modulated, a linear light source is obtained. Common specifications include 120×1 and 80×2. Under this light source, the divergence angle of the light source in the short axis direction is negligible relative to the long axis. In practice, it is often only necessary to control the divergence angle of the light source in the long axis direction. Therefore, more phase control is often performed on the long axis, and the short axis direction is almost unchanged. That is, the corresponding metasurface is generally constructed through formula 1 to generate the corresponding emission angle.

[0112] Taking a VCSEL chip with a design wavelength of 940nm, a substrate material of SiO2, a nanostructure material of single crystal silicon Si, and a cylindrical nanostructure as an example, in the design process, because different lattice constants correspond to different change curves, multiple different lattice constants are set, and the phase and transmittance of the target metasurface are constructed by the time-domain finite difference method. The change curve of the radius of the target nanounit is as follows: Figure 4 As shown, the lattice constant whose transmittance is always greater than 0.85 in the range of 0 to 2π is selected as the lattice constant of the target metasurface. Then, the target nanounits of the metasurface are discretized and uniformly set with the lattice constant, and the corresponding change curve is selected as the reference for the radius of the cylinder in each subsequent unit cell. Then, according to the angular energy corresponding to each unit cell, the corresponding phase distribution is obtained, as shown in Figure 5 As shown, based on the phase distribution, through the aforementioned formula 1, when the equivalent focal length, the position of the unit cell, and the wavelength are known, the phase difference that needs to be supplemented by the unit cell at that location can be easily calculated, and by referring to the change curve, through the relationship between the phase distribution and the cylindrical target nanounit, the radius of the required target nanounit can be deduced, and then the required nano-supersurface structure can be obtained.

[0113] Embodiment 3:

[0114] This embodiment provides a method for preparing a chip for modulating angular energy distribution, such as Figure 7 , 8 As shown, including:

[0115] S1: Etching on the VCSEL epitaxial wafer to obtain a mesa structure;

[0116] S2: wet oxidizing the mesa structure to form oxidation holes;

[0117] S3: growing SiO2 on the mesa structure;

[0118] S4: sequentially evaporating the P and N surface electrodes of the mesa structure by electron beam evaporation;

[0119] S5: performing high temperature annealing on the mesa structure to form an ohmic contact to form a VCSEL laser;

[0120] S6: growing a layer of super-surface dielectric material thin film on the emission hole of the VCSEL laser; the material of the super-surface dielectric material thin film is single crystal silicon;

[0121] S7: Processing the metasurface dielectric film on the VCSEL laser into a metasurface structure array capable of forming a linear outgoing laser beam through an etching process, wherein the metasurface structure is constructed according to a metasurface construction method for modulating angular energy distribution described in Example 1.

[0122] In this embodiment, by integrating the phase structure metasurface with the vertical cavity surface emitting laser (VCSEL), the line laser light source will become a chip-level product, and no longer needs to be produced in the form of an integrated module. Specifically, the structure of the target VCSEL chip is: from bottom to top, N electrode, GaAs substrate, buffer layer, NDBR (distributed Bragg reflector composed of AlGaAs with different components, n-type doping), quantum well active layer (MQW), oxide layer (oxide), PDBR (distributed Bragg reflector composed of AlGaAs with different components, p-type doping), contact layer, P electrode. The N electrode is placed under the GaAs substrate and contacts the GaAs substrate, and the P electrode is placed on the contact layer and contacts the contact layer. The silicon dioxide passivation layer covers the part of the device (except the electrode) that contacts the air.

[0123] When the device is in working state, the current is injected from the P-side annular electrode and flows out from the N-side electrode. The holes injected by the P electrode and the electrons injected by the N electrode reach the quantum well active layer area and undergo stimulated recombination in the quantum well active layer to generate light. The light oscillates between the NDBR and the PDBR, and finally emerges on the PDBR (lower reflectivity) side. The metasurface layer is made in the light exit hole (upper distributed Bragg reflector structure), and the spatial angular energy distribution of a multi-modal mixed light beam after passing through the metasurface layer will become a specified line laser beam. At the same time, the metasurface layer can also be set on the GaAs substrate. When the metasurface layer is set on the GaAs substrate, the NDBR reflectivity in the structure of the VCSEL decreases, the PDBR reflectivity increases, and the final PDBR reflectivity is close to 100%, and the NDBR reflectivity is lower than the PDBR. At this time, the light generated by the quantum well active layer of the device in the working state will oscillate between the NDBR and the PDBR, and finally emerge on the NDBR (lower reflectivity) side.

[0124] This embodiment integrates the phase structure metasurface with the vertical cavity surface emitting laser (VCSEL), and the light source will become a chip-level product, and no longer needs to be produced in the form of an integrated module. Compared with the existing technical solutions, it can greatly simplify the production process and size structure of the light source module.

[0125] Embodiment 4:

[0126] This embodiment provides a chip for modulating angular energy distribution, comprising an N electrode, a GaAs substrate, a buffer layer, an NDBR layer, a quantum well active layer, an oxide layer, a PDBR layer, a contact layer, and a P electrode arranged in sequence; wherein the N electrode is placed under the GaAs substrate and in contact with the GaAs substrate, and the P electrode is placed on the contact layer and in contact with the contact layer; the NDBR layer is composed of a distributed Bragg reflector composed of AlGaAs with different components and adopts n-type doping; the PDBR layer is composed of a distributed Bragg reflector composed of AlGaAs with different components and adopts p-type doping, and is characterized in that:

[0127] It also includes a super surface structure, which is constructed according to the super surface construction method for modulating angular energy distribution.

[0128] Although the preferred embodiments of the present invention have been described, those skilled in the art may make other changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

[0129] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A method for constructing a metasurface with modulated angular energy distribution, characterized in that: include: Obtaining a target wavelength of a target VCSEL chip, a target VCSEL chip structure, a target chip substrate material, a target nanounit structural material, and a target nanounit structure of a target nanounit; The target nanounit is disposed on a target supersurface; According to the target wavelength, the target VCSEL chip structure, the target chip substrate material, the target nanounit structure material, and the target nanounit structure, a curve diagram of the phase and transmittance of the target metasurface changing with the radius of the target nanounit is constructed by a time-domain finite difference method; According to the change curve, obtaining a lattice constant that maintains a target transmittance within a target range; Divide the target metasurface according to the lattice constant to obtain a metasurface unit cell set; According to the target angular energy distribution corresponding to each unit cell in the metasurface unit cell set, a corresponding target phase distribution is obtained; Searching the variation curve diagram according to the target phase distribution corresponding to the supersurface lattice in each of the supersurface unit cell sets to construct a corresponding supersurface target nanounit set; The target supersurface is constructed according to the target nanounit set and the supersurface unit cell set.

2. The method for constructing a metasurface with modulated angular energy distribution according to claim 1, characterized in that: The target phase distribution satisfies Among them, φ is the phase difference, f is the equivalent focal length of the field of view angle of the VCSEL chip using the target metasurface, x is the long axis direction coordinate of the unit cell at the field of view angle, y is the short axis direction coordinate of the unit cell at the field of view angle, and λ is the target wavelength.

3. The method for constructing a metasurface with modulated angular energy distribution according to claim 1, characterized in that: The target phase distribution satisfies Among them, φ is the phase difference, f is the equivalent focal length of the field of view angle of the VCSEL chip using the target metasurface, x is the long axis direction coordinate of the unit cell at the field of view angle, y is the short axis direction coordinate of the unit cell at the field of view angle, and λ is the target wavelength.

4. The method for constructing a metasurface with modulated angular energy distribution according to claim 1, characterized in that: The target nano-unit structure is a cylinder or a cube; the height of the target nano-unit is smaller than the target wavelength; after being modulated by the target metasurface, the light of the target VCSEL chip is modulated into a line light source.

5. A metasurface construction system for modulating angular energy distribution, characterized in that: include: A target parameter acquisition module is used to acquire a target wavelength of a target VCSEL chip, a target VCSEL chip structure, a target chip substrate material, a target nano-unit structural material, and a target nano-unit structure of a target nano-unit; the target nano-unit is arranged on a target metasurface; A phase relationship acquisition module, used to construct a curve diagram of the phase and transmittance of the target metasurface varying with the radius of the target nanounit by using a finite difference time domain method according to the target wavelength, the target VCSEL chip structure, the target chip substrate material, the target nanounit structure material, and the target nanounit structure; A lattice constant generating module, used for obtaining a lattice constant for maintaining a target transmittance within a target range according to the change curve diagram; A supersurface unit cell set acquisition module, used for dividing the target supersurface according to the lattice constant to acquire a supersurface unit cell set; A target energy distribution acquisition module, which acquires a corresponding target phase distribution according to a target angular energy distribution corresponding to each unit cell in the metasurface unit cell set; A target nanometer unit set acquisition module is used to find the change curve diagram according to the target phase distribution corresponding to the supersurface lattice in each of the supersurface unit cell sets, so as to construct a corresponding supersurface target nanometer unit set; The target supersurface construction module is used to construct the target supersurface according to the target nanounit set and the supersurface unit cell set.

6. The metasurface construction system for modulating angular energy distribution according to claim 5, characterized in that: The target phase distribution satisfies Among them, φ is the phase difference, f is the equivalent focal length of the field of view angle of the VCSEL chip using the target metasurface, x is the long axis direction coordinate of the unit cell at the field of view angle, y is the short axis direction coordinate of the unit cell at the field of view angle, and λ is the target wavelength.

7. The metasurface construction system for modulating angular energy distribution according to claim 5, characterized in that: The target phase distribution satisfies Among them, φ is the phase difference, f is the equivalent focal length of the field of view angle of the VCSEL chip using the target metasurface, x is the long axis direction coordinate of the unit cell at the field of view angle, y is the short axis direction coordinate of the unit cell at the field of view angle, and λ is the target wavelength.

8. The metasurface construction system for modulating angular energy distribution according to claim 5, characterized in that: The target nanometer unit structure is a cylinder or a cube, and the height of the target nanometer unit is smaller than the target wavelength.

9. A method for preparing a chip for modulating angular energy distribution, characterized in that: include: Etching is performed on the VCSEL epitaxial wafer to obtain a mesa structure; performing wet oxidation on the mesa structure to form oxidation holes; growing SiO2 on the mesa structure; Sequentially evaporating the P and N surface electrodes of the mesa structure by electron beam evaporation; Performing high temperature annealing on the mesa structure to form an ohmic contact to form a VCSEL laser; Growing a layer of super-surface dielectric material film on the emission hole of the VCSEL laser; the material of the super-surface dielectric material film is single crystal silicon; A metasurface dielectric material film is processed into a metasurface structure array that can form a linear outgoing laser beam on the VCSEL laser through an etching process, and the metasurface structure is constructed according to the metasurface construction method for modulating angular energy distribution according to any one of claims 1-4.

10. A chip for modulating angular energy distribution, comprising an N electrode, a GaAs substrate, a buffer layer, an NDBR layer, a quantum well active layer, an oxide layer, a PDBR layer, a contact layer, and a P electrode arranged in sequence; wherein: The N electrode is placed under the GaAs substrate and in contact with the GaAs substrate, and the P electrode is placed on the contact layer and in contact with the contact layer; the NDBR layer is composed of AlGaAs with different components to form a distributed Bragg reflector, using n-type doping; the PDBR layer is composed of AlGaAs with different components to form a distributed Bragg reflector, using p-type doping, characterized in that: It also includes a supersurface structure, which is constructed according to the supersurface construction method for modulating angular energy distribution according to any one of claims 1-4.

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