Achromatic superlens determination method, achromatic superlens and application assembly thereof

Abstract

The present disclosure provides an achromatic superlens determination method, an achromatic superlens and an application assembly thereof, applied to the field of lenses. The achromatic superlens comprises a metasurface. The method comprises: acquiring a microstructure parameter library, the microstructure parameter library comprising at least one piece of microstructure unit information; establishing a forward propagation model on the basis of the microstructure parameter library, and using the forward propagation model to simulate a process of incident light passing through a superlens to obtain a propagation result, the propagation result comprising an electric field component of at least one incident light at a first specified position; determining phase surface arrangement of a metasurface on the basis of the propagation result and a preset evaluation rule; and matching the phase surface arrangement with each group of microstructure unit information in the microstructure parameter library, and determining structure information of a microstructure unit correspondingly used at each position on the metasurface. In this way, a phase surface is optimized on the basis of the propagation result and the evaluation rule, and the design goal guidance for the microstructure units on the metasurface is given in combination with the microstructure unit information.

Description

Method for determining achromatic metalens, achromatic metalens and its application components

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to the Chinese patent application filed with the China Patent Office on August 1, 2023, with application number 202310955862.9, the entire contents of which are incorporated by reference into this application. Technical Field

[0003] The present disclosure relates to the field of lenses, and in particular to a method for determining an achromatic metalens, an achromatic metalens, and an application component thereof. Background Art

[0004] Metasurfaces, a new type of artificial material, enable efficient manipulation of various light parameters (such as frequency, amplitude, phase, and polarization) at subwavelength scales through the arrangement of microstructures on a substrate. Lenses designed using metasurface materials, known as superlenses, are thinner and lighter than traditional optical lenses. Multiple lenses can be simplified into a single layer or base layer of metasurface structure, facilitating the integration and miniaturization of imaging lens systems.

[0005] However, metalenses produce large chromatic aberrations, which affect their effectiveness. To address this issue, the related art provides a method for correcting metalense chromatic aberrations by using microstructure group delay to compensate for the chromatic aberration of the metasurface. However, for high numerical aperture achromatic metalenses, a higher group delay is required to achieve chromatic aberration compensation. Higher group delays correspond to microstructures with higher aspect ratios and more complex appearances, making the preparation of high numerical aperture achromatic metalenses more difficult.

[0006] Summary of the Invention

[0007] The present disclosure provides a method for determining an achromatic metalens, an achromatic metalens, and an application component thereof, to at least solve the above technical problems existing in the prior art.

[0008] In a first aspect, an embodiment of the present disclosure provides a method for determining an achromatic metalens, wherein the metalens includes a metasurface; the method includes:

[0009] Acquire a microstructure parameter library, wherein the microstructure parameter library includes: at least one microstructure unit information;

[0010] Establishing a forward propagation model based on the microstructure parameter library, and using the forward propagation model to simulate the process of incident light passing through the metalens to obtain a propagation result; the propagation result includes: at least one electric field component of the incident light at a first specified position;

[0011] Determining a phase plane arrangement of the metasurface according to the propagation results and a preset evaluation rule;

[0012] The phase plane arrangement is matched with each group of microstructure unit information in the microstructure parameter library to determine the structural information of the microstructure unit corresponding to each position on the metasurface.

[0013] In one example, each of the microstructure unit information includes:

[0014] Structural information of microstructure units;

[0015] Phase and transmittance of microstructure units under different wavelengths of incidence;

[0016] The structural information includes the size and shape of the microstructure unit.

[0017] In one embodiment, the forward propagation model is established according to the microstructure parameter library, and the forward propagation model is used to simulate the process of incident light passing through the metalens to obtain the propagation result, including:

[0018] Establishing the scattering field distribution of each microstructure unit under different incident light wavelengths according to the phase and transmittance of each microstructure unit in the microstructure parameter library;

[0019] Establishing the forward propagation model according to the scattering field distribution of each microstructure unit under different incident light wavelengths;

[0020] The Green's function method is adopted and the forward propagation model is used to simulate the process of incident light passing through the metalens, and at least one electric field component of the incident light at a first specified position is obtained as the propagation result.

[0021] In one example, determining the phase plane arrangement of the metasurface according to the propagation result and a preset evaluation rule includes:

[0022] Taking minimization of a preset first evaluation function as a goal, a phase plane corresponding to the minimum of the first evaluation function is determined according to the propagation result; the phase plane includes: a phase value required for each coordinate.

[0023] In one example, the first evaluation function is constructed according to the following information:

[0024] Preset focal length;

[0025] The wavelength of the incident light is λ i The electric field component at a specific location when

[0026] Among them, λ i is the wavelength of the i-th incident light.

[0027] In one embodiment, matching the phase plane arrangement with each set of microstructure unit information in the microstructure parameter library to determine the structural information of the microstructure unit corresponding to each position on the metasurface includes:

[0028] Matching the phase value required for each coordinate in the phase plane with the information of each microstructure unit in the microstructure parameter library, with the goal of minimizing a preset second evaluation function, determining the phase and transmittance of the microstructure unit corresponding to each coordinate on the metasurface when the second evaluation function is minimized;

[0029] According to the phase and transmittance of the microstructure unit corresponding to each coordinate on the metasurface, the structural information of the microstructure unit corresponding to each coordinate on the metasurface is determined.

[0030] In one example, the second evaluation function is constructed according to the following information:

[0031] The wavelength of the incident light is λ t The phase required at each coordinate on the metasurface when

[0032] The wavelength of the incident light is λ t The phase of the microstructure unit in the microstructure parameter library when

[0033] The wavelength of the incident light is λ t The transmittance of the microstructure unit in the microstructure parameter library;

[0034] A proportionality factor, which is used to adjust the importance of phase and transmittance in the matching process;

[0035] Among them, λ t for any wavelength.

[0036] In a second aspect, an embodiment of the present disclosure provides an achromatic metalens, wherein the metasurface is designed according to the structural information of the microstructure unit corresponding to each position on the metasurface determined by the method described in the first aspect to obtain the achromatic metalens with a high numerical aperture.

[0037] In a third aspect, an embodiment of the present disclosure provides a projection display device based on a superlens, the device comprising: an achromatic superlens and an optical waveguide structure as described in the second aspect; light is transmitted / reflected through the achromatic superlens to the optical waveguide structure, and is output in the optical waveguide structure according to a total reflection angle; the projection light output through the optical waveguide structure is coupled out to the human eye for imaging.

[0038] In one example, the optical waveguide structure includes a light incoupling device, an optical waveguide substrate, and a light outcoupling device, wherein the light incoupling device and the light outcoupling device are respectively located on opposite sides of the optical waveguide substrate;

[0039] The transmitted / reflected light is transmitted to the light coupling device, which couples the transmitted / reflected light into the optical waveguide substrate and outputs it to the light coupling device at a total reflection angle in the optical waveguide substrate. The light coupling device couples the transmitted / reflected light out to the human eye for imaging.

[0040] In one example, the optical waveguide substrate includes a first surface and a second surface opposite to each other, the second surface being the surface through which the light after transmission / reflection enters; the light coupling device is located on the first surface, or the light coupling device is located on the second surface.

[0041] In a fourth aspect, an embodiment of the present disclosure provides a wearable device, comprising: a shell; and a superlens-based projection display device as described in the third aspect, wherein the superlens-based projection display device is arranged in the shell.

[0042] In one embodiment, the wearable device further includes an eye tracking device, which includes an eye tracking light source, a sensor, and an information processing system, wherein the eye tracking light source projects light to the human eye, the sensor receives the light reflected by the human eye, and the information processing system processes the information in the sensor and performs corresponding human-computer interaction actions.

[0043] In a fifth aspect, an embodiment of the present disclosure provides an electronic device, comprising: at least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores instructions executable by the at least one processor, and the instructions are executed by the at least one processor to enable the at least one processor to perform the method for determining the achromatic metalens described in the first aspect.

[0044] The disclosed embodiments provide a method for determining an achromatic metalens, an achromatic metalens, and an application component thereof, wherein the metalens includes a metasurface; the method includes: obtaining a microstructure parameter library, the microstructure parameter library including: information of at least one microstructure unit; establishing a forward propagation model based on the microstructure parameter library, using the forward propagation model to simulate the process of incident light passing through the metalens to obtain a propagation result; the propagation result includes: an electric field component of at least one incident light at a first specified position; determining a phase plane arrangement of the metasurface based on the propagation result and a preset evaluation rule; matching the phase plane arrangement with each group of microstructure unit information in the microstructure parameter library to determine the size and shape of the microstructure unit corresponding to each position on the metasurface. In this way, the phase plane is optimized based on the propagation result and the evaluation rule, and combined with the microstructure unit information, a design target guidance for the microstructure unit on the metasurface is provided.

[0045] It should be understood that the contents described in this section are not intended to identify the key or important features of the embodiments of the present disclosure, nor are they intended to limit the scope of the present disclosure. Other features of the present disclosure will become readily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] FIG1 is a schematic flow chart of a method for determining an achromatic metalens according to an embodiment of the present disclosure;

[0047] FIG2 is a schematic structural diagram of an achromatic metalens provided in an embodiment of the present disclosure;

[0048] FIG3 is a schematic structural diagram of a microstructure unit of a metasurface provided by an embodiment of the present disclosure;

[0049] FIG4 is a schematic diagram of an optimized phase plane provided by an embodiment of the present disclosure;

[0050] FIG5 is a schematic diagram of the focusing result of the achromatic metalens provided by an embodiment of the present disclosure;

[0051] FIG6 is a schematic flow chart of a method for designing an achromatic metalens according to an embodiment of the present disclosure;

[0052] FIG7 is a schematic structural diagram of a device for determining an achromatic metalens provided in an embodiment of the present disclosure;

[0053] FIG8 is a schematic structural diagram of an electronic device provided by an embodiment of the present disclosure;

[0054] FIG9 is a schematic structural diagram of a projection display device (light is transmitted through an achromatic superlens to an optical waveguide structure) provided in an embodiment of the present disclosure;

[0055] FIG10 is a schematic structural diagram of a projection display device (light is reflected to an optical waveguide structure by an achromatic superlens) provided in an embodiment of the present disclosure;

[0056] FIG11 is a schematic structural diagram of an optical waveguide structure (the light coupling device is located on the second surface) provided in an embodiment of the present disclosure;

[0057] FIG12 is a schematic structural diagram of an optical waveguide structure (the light coupling device is located on the first surface) provided in an embodiment of the present disclosure;

[0058] FIG13 is a schematic diagram of the structure of an eye tracking device provided by an embodiment of the present disclosure;

[0059] FIG14 is a schematic diagram of the structure of the sensor in the eye tracking device provided in an embodiment of the present disclosure. DETAILED DESCRIPTION

[0060] To make the purposes, features, and advantages of the present disclosure more apparent and understandable, the technical solutions in the embodiments of the present disclosure will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present disclosure, not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present disclosure without creative work shall fall within the scope of protection of the present disclosure.

[0061] In the following description, reference is made to “some embodiments”, which describes a subset of all possible embodiments, but it will be understood that “some embodiments” may be the same subset or different subsets of all possible embodiments and may be combined with each other without conflict.

[0062] In the following description, the terms "first\second" are merely used to distinguish similar objects and do not represent a specific ordering of the objects. It is understandable that "first\second" can be interchanged with a specific order or sequence where permitted, so that the embodiments of the present disclosure described herein can be implemented in an order other than that illustrated or described herein.

[0063] Unless otherwise defined, all technical and scientific terms used in this disclosure have the same meaning as commonly understood by those skilled in the art in the art of this disclosure. The terms used in this disclosure are only for the purpose of describing the embodiments of this disclosure and are not intended to limit this disclosure.

[0064] It should be understood that in the various embodiments of the present disclosure, the size of the serial number of each implementation process does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present disclosure.

[0065] The present disclosure provides a method for determining an achromatic metalens, wherein the metalens includes a metasurface. As shown in FIG1 , the method includes:

[0066] Step 101: Acquire a microstructure parameter library, wherein the microstructure parameter library includes: information of at least one microstructure unit;

[0067] Step 102: establishing a forward propagation model based on the microstructure parameter library, and using the forward propagation model to simulate the process of incident light passing through the metalens to obtain a propagation result; the propagation result includes: at least one electric field component of the incident light at a first specified position;

[0068] Step 103: determining the phase plane arrangement of the metasurface according to the propagation result and a preset evaluation rule;

[0069] Step 104: Match the phase plane arrangement with each group of microstructure unit information in the microstructure parameter library to determine the structural information of the microstructure unit corresponding to each position on the metasurface.

[0070] Specifically, the metalens is also called a metasurface lens, and the metalens can specifically be an achromatic metasurface lens with a high numerical aperture.

[0071] As shown in FIG2 , a schematic diagram of the structure of an achromatic metalens provided in an embodiment of the present disclosure is shown. The metasurface of the achromatic metalens includes:

[0072] A substrate that can transmit light in wavelengths including visible light and infrared light;

[0073] A microstructure unit array is placed on one side of the substrate.

[0074] The microstructure units are arranged in an array in a certain pattern. The microstructure units can be nanopillar structures, such as circular nanopillars, hollow nanopillars, and other structures, or other structures obtained through topological optimization, neural networks, and the structural dimensions of the microstructure units are not limited.

[0075] The material of the substrate may be any one or more of silicon dioxide, aluminum oxide, and calcium fluoride.

[0076] The material of the microstructure unit of the nanocolumn structure may be any one or more of titanium oxide, gallium nitride, amorphous silicon, and polycrystalline silicon.

[0077] In some embodiments, each of the microstructure unit information may include:

[0078] Structural information of microstructure units;

[0079] Phase and transmittance of microstructure units under different wavelengths of incidence;

[0080] The structural information includes the size and shape of the microstructure unit.

[0081] Specifically, by changing the size and shape of the microstructure unit, a parameter library of phase distribution, transmittance and structural parameters under different wavelengths of incidence is obtained.

[0082] As shown in Figure 3, it is a structural schematic diagram of a microstructure unit of a metasurface provided in an embodiment of the present disclosure; the microstructure unit 2 can be a hollow nanocolumn having inner diameter (Rin) and outer diameter (Rout) parameters; the microstructure unit 2 is arranged on a substrate 1.

[0083] If the microstructure unit 2 is a circular nanocolumn, the microstructure unit 2 has an Rout parameter.

[0084] By designing a variety of Rin parameters, Rout parameters, or microstructure units with different Rout parameters, and measuring the phase and transmittance of the microstructure units under different wavelengths of incidence, a microstructure parameter library is obtained. Any existing phase and transmittance measurement method can be used here, and there is no limitation on the measurement method.

[0085] The phase and transmittance of microstructure units with different structures at different wavelengths are also different. Changing the Rout parameter causes the phase and transmittance of each microstructure unit to change.

[0086] In some embodiments, establishing a forward propagation model based on the microstructure parameter library and using the forward propagation model to simulate the process of incident light passing through the metalens to obtain a propagation result includes:

[0087] Establishing the scattering field distribution of each microstructure unit under different incident light wavelengths according to the phase and transmittance of each microstructure unit in the microstructure parameter library;

[0088] Establishing the forward propagation model according to the scattering field distribution of each microstructure unit under different incident light wavelengths;

[0089] The Green's function method is adopted and the forward propagation model is used to simulate the process of incident light passing through the metalens, and at least one electric field component of the incident light at a first specified position is obtained as the propagation result.

[0090] Specifically, according to the phase and transmittance of each microstructure unit in the microstructure parameter library, the scattering field distribution of each microstructure unit under different incident light wavelengths is established, which is recorded as s(x i ,y i ,z i ,λ i ); where λ i is the wavelength of the i-th incident light; that is, s is the wavelength of the incident light λ i When the coordinates on the hypersurface are (x i ,y i ,z i ) at the scattered field distribution; here, the way to establish the scattered field distribution can adopt any existing one, and there is no limitation on the specific method adopted.

[0091] According to the scattering field distribution of each microstructure unit under different incident light wavelengths, the forward propagation model is established, as shown in formula (1): E(x o ,y o ,z o ,λ i )=∫∫s(x i ,y i ,z i ,λi )G(x i ,y i ,z i ,x o ,y o ,z o ,λ i )dx i dy i (1)

[0092] Where E is the wavelength of the incident light λ i , the first specified position (x o ,y o ,z o ) at the electric field component;

[0093] λ i is the wavelength of the i-th incident light; the specific value is determined according to the actual situation;

[0094] s is the wavelength of incident light λ i When the coordinates on the hypersurface are (x i ,y i ,z i ) at the scattered field distribution;

[0095] G is the Hankel function, which is related to the wavelength λ of the incident light i , the coordinates of the first specified position (x o ,y o ,z o ) and the coordinates on the hypersurface (x i ,y i ,z i ) are all relevant.

[0096] Here, the Green's function method is used to calculate the forward propagation model and obtain the intensity distribution at the first specified position when the incident light passes through the metalens. This process can also be calculated using the FDTD algorithm and vector angular spectrum analysis method, which will not be detailed here.

[0097] Assume that the method provided in the embodiment of the present disclosure is used to implement a design method for a high numerical aperture achromatic metalens, whose operating band is 400nm to 700nm, the metalens diameter is 200μm, and the focal length is 100μm. The structure of the achromatic metalens is shown in Figure 2. Here, for the metalens required above, the process of incident light passing through the metalens is simulated and the above formula (1) is used for calculation.

[0098] In some embodiments, determining the phase plane arrangement of the metasurface according to the propagation result and a preset evaluation rule includes:

[0099] Taking the minimum of the preset first evaluation function as the goal, the phase plane corresponding to the minimum of the first evaluation function is determined according to the propagation result; the phase plane includes: each coordinate (x i ,y i )The desired phase value.

[0100] The first evaluation function is constructed according to the following information:

[0101] Preset focal length;

[0102] The wavelength of the incident light is λ i The electric field component at a specific location when .

[0103] Specifically, a first evaluation function is provided, as shown in the following formula (2):

[0104] Among them, f design is the pre-set focal length;

[0105] N is the total number of incident light wavelengths;

[0106] λ i is the wavelength of the i-th incident light, and its specific value is determined according to the actual situation; for example, λ i For example, it can be 450nm, 532nm, 632nm;

[0107] E represents the wavelength of the incident light, λ i When the specific position (0,0,z o )'s electric field component.

[0108] Here, (0,0,z o ) specifically refers to the center point when the x and y coordinate values ​​are 0. By determining the z o , determine the z-axis coordinate as z o When each (x i ,y i ) to obtain the phase value required by the first evaluation function, and obtain the phase surface corresponding to the minimum of the first evaluation function, which is recorded as

[0109] As shown in FIG4 , a schematic diagram of a phase plane distribution obtained by an optimization method provided in an embodiment of the present disclosure is shown; by optimizing the phase arrangement, the phase plane distribution shown in FIG4 can be obtained and denoted as For example, i In the range of 450-632 nm, specifically, it can be 450 nm, 532 nm and 632 nm.

[0110] In some embodiments, matching the phase plane arrangement with each set of microstructure unit information in the microstructure parameter library to determine the structural information of the microstructure unit corresponding to each position on the metasurface includes:

[0111] Matching the phase value required for each coordinate in the phase plane with the information of each microstructure unit in the microstructure parameter library, with the goal of minimizing a preset second evaluation function, determining the phase and transmittance of the microstructure unit corresponding to each coordinate on the metasurface when the second evaluation function is minimized;

[0112] According to the phase and transmittance of the microstructure unit corresponding to each coordinate on the metasurface, the structural information of the microstructure unit corresponding to each coordinate on the metasurface is determined.

[0113] The second evaluation function is constructed according to the following information:

[0114] The wavelength of the incident light is λ t The phase required at each coordinate on the metasurface when

[0115] The wavelength of the incident light is λ t The phase of the microstructure unit in the microstructure parameter library when

[0116] The wavelength of the incident light is λ t The transmittance of the microstructure unit in the microstructure parameter library;

[0117] A proportionality factor, which is used to adjust the importance of phase and transmittance in the matching process;

[0118] Among them, λ t for any wavelength.

[0119] Here, the coordinates of the phase plane are actually the coordinates of the metasurface, and the phase required at each coordinate on the metasurface is the phase required at each coordinate on the phase plane.

[0120] Specifically, the obtained phase surface distribution is matched with the phase in the microstructure parameter library so that each position on the metasurface has the closest At the same time, in order to have a higher transmittance, matching is performed according to the following formula (3):

[0121] Where, Indicates that the wavelength of the incident light is λ t When the super surface (x i ,y i ) required phase;

[0122] n is the total number of incident light wavelengths;

[0123] Indicates that the wavelength of the incident light is λ t When , the phase of a microstructure unit in the microstructure parameter library;

[0124] T real (λ t ) indicates that the wavelength of the incident light is λ t When , the transmittance of a certain microstructure unit in the microstructure parameter library;

[0125] α and β are proportional coefficients, which are used to adjust the importance of phase and transmittance in the matching process. The higher the proportional coefficient, the more attention is paid to the influence of this parameter. There is no limit on the values ​​of α and β, which are determined according to actual needs.

[0126] According to the above process, the corresponding metasurface structure of the achromatic metalens can be obtained, thereby realizing achromatic focusing of multiple wavelengths.

[0127] In some embodiments, the method further comprises:

[0128] According to the determined structural information (size and shape) of the microstructure unit corresponding to each position on the metasurface, the metasurface is designed to obtain an achromatic metasurface lens with a high numerical aperture.

[0129] The method provided by the disclosed embodiments utilizes an optimization algorithm to optimize the phase surface design, obtaining the optimal achromatic metalens phase surface. Based on the optimization results, feedback is provided on the phase of the desired microstructure unit, and the parameters of the microstructure unit are then optimized in a targeted manner. By topologically optimizing the phase surface, the numerical aperture limitation of the achromatic metalens achieved by using dispersion compensation is avoided, enabling high numerical aperture achromatic focusing. This achromatic lens can be used in consumer electronics imaging lenses, reducing the thickness and weight of the lens.

[0130] FIG5 is a schematic diagram of the focusing results of an achromatic metalens provided by an embodiment of the present disclosure. As shown in FIG5 , under incident wavelengths of 450 nm, 532 nm, and 632 nm, the achromatic metalens has almost identical focal lengths of 99 μm, 100.2 μm, and 101.2 μm, respectively, which can meet the achromatic requirements.

[0131] FIG6 is a flow chart of a method for designing an achromatic metalens according to an embodiment of the present disclosure. As shown in FIG6 , the method includes:

[0132] Step 701: Change the size and shape of the microstructure unit to obtain the phase and transmittance of each microstructure unit under incident light waves of different wavelengths; and construct a microstructure parameter library based on the size, shape, phase and transmittance of each microstructure unit;

[0133] Step 702: Use the microstructure parameter library to establish a forward propagation model to simulate the process of incident light passing through the metalens to obtain simulation results;

[0134] Step 703: Analyze the simulation results according to the evaluation function and perform iterative optimization;

[0135] Here, the evaluation function may adopt the above formula 2. The specific method is referred to the corresponding description in the method of FIG1 , which will not be repeated here.

[0136] Here, the method may further include:

[0137] If the current microstructure parameter library cannot achieve good results, the microstructure unit size and shape can be further optimized based on the required phase delay to supplement the microstructure parameter library. This step is optional and should be performed based on actual conditions.

[0138] Step 704: Obtain a metalens that meets achromatic performance.

[0139] Specifically, an achromatic metalens is constructed based on the obtained optimal solution of microstructure size, shape, and arrangement. For details, please refer to the description of the method shown in FIG1 , which will not be repeated here.

[0140] FIG7 is a schematic diagram of the structure of a device for determining an achromatic metalens provided in an embodiment of the present disclosure. As shown in FIG7 , the metalens includes a metasurface, and the device includes:

[0141] An acquisition module, configured to acquire a microstructure parameter library, wherein the microstructure parameter library includes: information of at least one microstructure unit;

[0142] a processing module, configured to establish a forward propagation model based on the microstructure parameter library, and use the forward propagation model to simulate a process of incident light passing through the metalens to obtain a propagation result; the propagation result includes: at least one electric field component of the incident light at a first specified position;

[0143] an optimization module, configured to determine a phase plane arrangement of the metasurface based on the propagation results and preset evaluation rules;

[0144] A determination module is used to match the phase plane arrangement with each group of microstructure unit information in the microstructure parameter library to determine the structural information of the microstructure unit corresponding to each position on the metasurface.

[0145] It is understood that when implementing the corresponding achromatic metalens determination method, the achromatic metalens determination device provided in the above-described embodiments can, as needed, assign the above-described processing to different program modules to complete all or part of the above-described processing. Furthermore, the device provided in the above-described embodiments and the corresponding method embodiments are based on the same concept. The specific implementation process is detailed in the method embodiments and will not be further described here.

[0146] The embodiments of the present disclosure provide a computer-readable storage medium storing executable instructions. The executable instructions, when executed by a processor, trigger the processor to execute the method for determining an achromatic metalens provided in the embodiments of the present disclosure.

[0147] In some embodiments, the computer-readable storage medium may be a ferroelectric random access memory (FRAM), a read-only memory (ROM), a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), an electrically erasable programmable read-only memory (EEPROM), a flash memory, a magnetic surface memory, an optical disk, or a CD-ROM; or various devices including one or any combination of the above memories.

[0148] In some embodiments, executable instructions may be in the form of a program, software, software module, script, or code, written in any form of programming language (including compiled or interpreted languages, or declarative or procedural languages), and which may be deployed in any form, including as a stand-alone program or as a module, model, subroutine, or other unit suitable for use in a computing environment.

[0149] By way of example, executable instructions may be deployed to be executed on one computing device, or on multiple computing devices at one site, or on multiple computing devices distributed across multiple sites and interconnected by a communication network.

[0150] An embodiment of the present disclosure provides a computer program product, which includes a computer program / instructions. When the computer program / instructions are executed by a processor, the method for determining the achromatic metalens described in the present disclosure is implemented.

[0151] FIG8 is a schematic diagram of the structure of an electronic device provided in an embodiment of the present disclosure. As shown in FIG8 , the electronic device 90 includes: a processor 901 and a memory 902 for storing a computer program that can be run on the processor; the processor 901 is configured to execute the method for determining an achromatic metalens provided in an embodiment of the present disclosure when running the computer program.

[0152] In actual application, the electronic device 90 may further include: at least one network interface 903. The various components in the electronic device 90 are coupled together via a bus system 904. It will be understood that the bus system 904 is used to implement connection and communication between these components. In addition to the data bus, the bus system 904 also includes a power bus, a control bus, and a status signal bus. However, for the sake of clarity, various buses are labeled as the bus system 904 in Figure 8. The number of processors 901 can be at least one. The network interface 903 is used for wired or wireless communication between the electronic device 90 and other devices.

[0153] The memory 902 in the embodiment of the present disclosure is used to store various types of data to support the operation of the electronic device 90 .

[0154] The methods disclosed in the above embodiments of the present disclosure can be applied to or implemented by processor 901. Processor 901 may be an integrated circuit chip with signal processing capabilities. During implementation, each step of the above method can be completed by hardware integrated logic circuits in processor 901 or by software instructions. The above processor 901 may be a general-purpose processor, a digital signal processor (DSP), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. Processor 901 can implement or execute the various methods, steps, and logic block diagrams disclosed in the embodiments of the present disclosure. A general-purpose processor may be a microprocessor or any conventional processor. The steps of the methods disclosed in conjunction with the embodiments of the present disclosure can be directly implemented as being executed by a hardware decoding processor, or can be executed by a combination of hardware and software modules in the decoding processor. The software module can be located in a storage medium located in memory 902. Processor 901 reads information in memory 902 and, in conjunction with its hardware, completes the steps of the above method.

[0155] In some embodiments, the electronic device 90 can be implemented by one or more application-specific integrated circuits (ASICs), DSPs, programmable logic devices (PLDs), complex programmable logic devices (CPLDs), field-programmable gate arrays (FPGAs), general-purpose processors, controllers, microcontrollers (MCUs), microprocessors, or other electronic components to execute the aforementioned method.

[0156] 9 and 10 , embodiments of the present disclosure further provide a metalens-based projection display device, wherein the device includes: an achromatic metalens 3 obtained by processing using any of the above methods and an optical waveguide structure 4. Light is transmitted / reflected through the achromatic metalens 3 to the optical waveguide structure 4, and is output from the optical waveguide structure 4 at a total internal reflection angle. The projected light output from the optical waveguide structure 4 is coupled out to the human eye for imaging.

[0157] In one embodiment, the optical waveguide structure 4 includes a light incoupling device 41, a light waveguide substrate 42, and a light outcoupling device 43. The light incoupling device 41 and the light outcoupling device 43 are respectively located on opposite sides of the light waveguide substrate 42.

[0158] The transmitted / reflected light is transmitted to the light coupling device 41, which couples the transmitted / reflected light into the optical waveguide substrate 42, and performs total reflection in the optical waveguide substrate 42 to output the light to the light coupling device 43, which couples the transmitted / reflected light out to the human eye for imaging.

[0159] The light coupling device 41 is composed of a metalens or a group of metalens. The light coupling device 41 can adjust the angle of the transmitted / reflected light so that the transmitted / reflected light can be input into the optical waveguide substrate 42 according to the critical angle and propagate forward along the total internal reflection in the optical waveguide substrate 42. The angle modulation of the projected light (e.g., the transmitted / reflected light) by the light coupling device 41 satisfies the following formula (4):

[0160] in, is the angle of the projection light emitted through the light coupling device 41 , n1 is the refractive index of the projection light in air, and n2 is the refractive index of the projection light in the optical waveguide substrate 42 .

[0161] An optical waveguide substrate is typically made of a material with a high refractive index, such as glass or plastic, and features a central core surrounded by an outer layer. When light enters the waveguide substrate, it is reflected at the interface between the core and the outer layer due to total internal reflection, thereby propagating along the waveguide substrate. By controlling the angle and position of the incident light, total internal reflection can be achieved within the waveguide substrate, thereby controlling the light's propagation path and the resulting display position.

[0162] Both the light coupling device and the light coupling device adopt an achromatic design, which can eliminate the chromatic aberration of the projection light.

[0163] Optical waveguide substrates play a crucial role in AR glasses, guiding light from displays or projectors to the metalens or reflectors near the eyes, enabling observation of virtual images. By properly designing the optical waveguide structure and controlling the incident angle of light, a high-quality augmented reality experience can be achieved.

[0164] In one embodiment, the optical waveguide substrate 42 includes a first surface 401 and a second surface 402 opposite to each other. The second surface 402 is the surface where the light enters after transmission / reflection. The light coupling device 41 is located on the first surface 401 or on the second surface 402.

[0165] FIG11 is a schematic structural diagram of an optical waveguide structure (the light coupling device 41 is located on the second surface 402 ) provided in an embodiment of the present disclosure. As shown in FIG11 , the light coupling device is located on the second surface.

[0166] FIG12 is a schematic structural diagram of an optical waveguide structure (the light coupling device 41 is located on the first surface 401 ) provided in an embodiment of the present disclosure; as shown in FIG12 , the light coupling device is located on the first surface 401 .

[0167] An embodiment of the present disclosure also provides a wearable device, which includes a shell; and a superlens-based projection display device as described in any one of the above embodiments, wherein the superlens-based projection display device is arranged in the shell.

[0168] Referring to Figure 13, the wearable device also includes an eye tracking device, which includes an eye tracking light source, a sensor and an information processing system. The eye tracking light source projects light to the human eye, the sensor receives the light reflected by the human eye, and the information processing system processes the information in the sensor and performs corresponding human-computer interaction actions, thereby increasing the intelligence of the AR glasses.

[0169] Referring to Figure 14, the sensor of the eye tracking device of the embodiment of the present disclosure uses semiconductor technology to integrate the metalens and sensor chip into one device, which greatly improves the integration and processing degree of the device, improves the wearability of AR glasses, and reduces costs.

[0170] Wearable devices include head-mounted display devices, such as AR glasses or AR helmets. In this case, the projection display device can form an AR projection light machine, for example. Of course, the wearable device can also be a VR product, etc., which is not limited in the embodiments of the present application.

[0171] In addition, the projection display device provided in the embodiments of the present disclosure can also be used in other types of projection devices such as home projectors and car projectors, etc., which is not limited in the embodiments of the present disclosure.

[0172] It should be understood that the various forms of the processes shown above can be used to reorder, add, or delete steps. For example, the steps described in this disclosure can be performed in parallel, sequentially, or in a different order, as long as the desired results of the technical solutions disclosed in this disclosure can be achieved. This is not limited herein.

[0173] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. Throughout the present disclosure, "plurality" means two or more, unless otherwise specifically defined.

[0174] The above description is merely a specific embodiment of the present disclosure, but the scope of protection of the present disclosure is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this disclosure should be included in the scope of protection of the present disclosure. Therefore, the scope of protection of the present disclosure should be based on the scope of protection of the claims.

Claims

1. A method for determining an achromatic metalens, wherein: The metalens comprises a metasurface; the method comprises: Acquire a microstructure parameter library, wherein the microstructure parameter library includes: at least one microstructure unit information; A forward propagation model is established according to the microstructure parameter library, and the forward propagation model is used to simulate the process of incident light passing through the metalens to obtain a propagation result; the propagation result includes: at least one electric field component of the incident light at a first specified position; Determining a phase plane arrangement of the metasurface according to the propagation result and a preset evaluation rule; The phase plane arrangement is matched with each group of microstructure unit information in the microstructure parameter library to determine the structural information of the microstructure unit corresponding to each position on the metasurface.

2. The method according to claim 1, wherein: Each of the microstructure unit information includes: Structural information of microstructure units; Phase and transmittance of microstructure units under different wavelengths of incidence; The structural information includes: the size and shape of the microstructure unit.

3. The method according to claim 1, wherein: The forward propagation model is established according to the microstructure parameter library, and the forward propagation model is used to simulate the process of incident light passing through the super lens to obtain the propagation result, including: According to the phase and transmittance of each microstructure unit in the microstructure parameter library, a scattering field distribution of each microstructure unit under different incident light wavelengths is established; Establishing the forward propagation model according to the scattering field distribution of each microstructure unit under different incident light wavelengths; The Green's function method is adopted and the forward propagation model is used to simulate the process of incident light passing through the metalens, and at least one electric field component of the incident light at a first specified position is obtained as the propagation result.

4. The method according to claim 1, wherein: Determining the phase plane arrangement of the metasurface according to the propagation result and a preset evaluation rule includes: Taking the minimum of the preset first evaluation function as the goal, the phase plane corresponding to the minimum of the first evaluation function is determined according to the propagation result; the phase plane includes: the phase value required for each coordinate.

5. The method according to claim 4, wherein: The first evaluation function is constructed according to the following information: Preset focal length; The wavelength of incident light is λ i The electric field component at a specific location when Among them, λ i is the wavelength of the i-th incident light.

6. The method according to claim 1, wherein: The matching of the phase plane arrangement with each group of microstructure unit information in the microstructure parameter library to determine the structural information of the microstructure unit corresponding to each position on the metasurface includes: Matching the phase value required for each coordinate in the phase plane with the information of each microstructure unit in the microstructure parameter library, with the goal of minimizing a preset second evaluation function, determining the phase and transmittance of the microstructure unit corresponding to each coordinate on the metasurface when the second evaluation function is minimized; According to the phase and transmittance of the microstructure unit corresponding to each coordinate on the metasurface, the structural information of the microstructure unit corresponding to each coordinate on the metasurface is determined.

7. The method according to claim 6, wherein: The second evaluation function is constructed according to the following information: The wavelength of incident light is λ t The phase required at each coordinate on the metasurface when The wavelength of incident light is λ t The phase of the microstructure unit in the microstructure parameter library when The wavelength of incident light is λ t The transmittance of the microstructure unit in the microstructure parameter library; A proportionality coefficient, which is used to adjust the importance of phase and transmittance in the matching process; Among them, λ t for any wavelength.

8. An achromatic metalens, wherein: According to the structural information of the microstructure unit corresponding to each position on the metasurface determined by the method according to any one of claims 1 to 7, the metasurface is designed to obtain the achromatic metalens with a high numerical aperture.

9. A projection display device based on a superlens, wherein: The device comprises: the achromatic superlens and optical waveguide structure as claimed in claim 8; The light is transmitted / reflected to the optical waveguide structure through the achromatic superlens, and is output in the optical waveguide structure according to the total reflection angle; the projection light output through the optical waveguide structure is coupled out to the human eye for imaging.

10. The projection display device based on a superlens according to claim 9, wherein: The optical waveguide structure comprises an optical coupling device, an optical waveguide substrate and an optical coupling device, wherein the optical coupling device and the optical coupling device are respectively located on two opposite sides of the optical waveguide substrate; The transmitted / reflected light is transmitted to the light coupling device, and the light coupling device couples the transmitted / reflected light into the optical waveguide substrate, and performs total reflection angle output in the optical waveguide substrate to the light coupling device, and the light coupling device couples the transmitted / reflected light out to the human eye for imaging.

11. The projection display device based on a superlens according to claim 10, wherein: The optical waveguide substrate comprises a first surface and a second surface opposite to each other, wherein the second surface is the surface where the light after transmission / reflection enters; the light coupling device is located on the first surface, or the light coupling device is located on the second surface.

12. A wearable device, wherein: include: case; as well as The superlens-based projection display device as described in any one of claims 9 to 11, wherein the superlens-based projection display device is arranged in the housing.

13. The wearable device according to claim 12, wherein: Also includes: An eye tracking device, comprising an eye tracking light source, a sensor and an information processing system, wherein the eye tracking light source projects light to the human eye, the sensor receives the light reflected by the human eye, and the information processing system processes the information in the sensor and performs corresponding human-computer interaction actions.

14. An electronic device, wherein: include: at least one processor; as well as a memory communicatively connected to the at least one processor; wherein, The memory stores instructions that can be executed by the at least one processor, and the instructions are executed by the at least one processor to enable the at least one processor to perform the method according to any one of claims 1 to 7.

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