Light field distribution testing method and device for multi-wavelength optical diffraction metasurface chips

Abstract

The present application relates to a method and apparatus for testing the light field distribution of a multi-wavelength optical diffraction metasurface chip, and relates to the technical field of optical testing. The light field distribution testing method comprises: receiving lasers of multiple wavelengths; processing the lasers of multiple wavelengths to obtain a light field distribution for testing; loading the light field distribution for testing onto a metasurface chip to obtain a diffracted light field distribution after passing through the metasurface chip; measuring the diffracted light field distribution to obtain light field information at the focal plane of the measurement position; and adjusting the measurement position to obtain a mapping relationship between the light field information and the measurement position. The light field distribution testing method provided in this application can improve the efficiency of metasurface chip testing.

Description

Technical Field

[0001] The present application relates to the technical field of optical testing, and in particular to a method and device for testing the light field distribution of a multi-wavelength optical diffraction metasurface chip. Background Art

[0002] Optical neural networks are photonic chips that use photons as information carriers, while metasurface chips are optical chips that utilize metasurface structures to flexibly and effectively control properties such as light diffraction. The combination of metasurface chips and optical diffraction neural networks has become a key component in achieving high-degree-of-freedom cascaded diffraction neural networks within optical neural networks. Achieving these functions requires precise testing of the metasurface chip.

[0003] Currently, general metasurface chip testing devices use a fixed-wavelength laser to generate a single specific wavelength, combined with CCD (charge-coupled device) imaging to form a static optical path. The output light field is then modulated, diffracted over a specific distance, and the results are output to complete the test.

[0004] However, the inventors of this application discovered that, during the testing process, the method of using a single specific wavelength and a fixed optical path with a determined diffraction distance for functional demonstration cannot achieve universal and precise characterization of metasurfaces of multiple wavelengths, thereby reducing the testing efficiency of metasurface chips.

[0005] The contents of the background technology section are merely technologies known to the public and do not necessarily represent the existing technologies in this field. Summary of the Invention

[0006] The present application provides a light field distribution testing method and device for a multi-wavelength optical diffraction metasurface chip, which is used to solve the problem of low testing efficiency of metasurface chips.

[0007] According to one aspect of the present application, the present application provides a light field distribution testing method for a multi-wavelength optical diffraction metasurface chip, including: receiving lasers of multiple bands; processing lasers of multiple bands to obtain the light field distribution used for testing; loading the light field distribution used for testing onto the metasurface chip to obtain the diffraction light field distribution after passing through the metasurface chip; measuring the diffraction light field distribution to obtain light field information of the focal plane at the measurement position; adjusting the measurement position to obtain a mapping relationship between the light field information and the measurement position.

[0008] According to some embodiments of the present application, processing lasers of multiple wavelength bands to obtain a light field distribution used for testing includes: preprocessing lasers of multiple wavelength bands to obtain an initial laser; secondary processing the initial laser to obtain a target laser; splitting the target laser to obtain a first laser and a second laser; measuring the first laser to obtain parameter information of the first laser; and when confirming that the parameter information is the same as a preset experimental value, modulating the second laser to obtain the light field distribution used for testing.

[0009] According to some embodiments of the present application, pre-processing the laser beams of multiple wavelength bands to obtain the initial laser beam includes: filtering the laser beams of multiple wavelength bands based on a preset wavelength value to obtain the initial laser beam.

[0010] According to some embodiments of the present application, secondary processing of the initial laser to obtain the target laser includes: adjusting the spot size and divergence angle of the initial laser to obtain the target laser.

[0011] According to some embodiments of the present application, the parameter information includes wavelength parameters, and measuring the first laser to obtain the parameter information of the first laser includes: decomposing the first laser to obtain discrete wavelength components; and measuring the discrete wavelength components to obtain the wavelength parameters of the first laser.

[0012] According to some embodiments of the present application, the parameter information includes a half-width parameter, and measuring the first laser to obtain the parameter information of the first laser includes: separating adjacent wavelengths of the first laser to obtain discrete monochromatic spectral lines; and measuring the discrete monochromatic spectral lines to obtain the half-width parameter of the first laser.

[0013] According to some embodiments of the present application, loading the light field distribution used for testing onto the metasurface chip to obtain the diffraction light field distribution after passing through the metasurface chip includes: adjusting the shape of the light field distribution used for testing to obtain the target light field distribution; loading the target light field distribution onto the metasurface chip to obtain the diffraction light field distribution.

[0014] According to some embodiments of the present application, adjusting the measurement position to obtain a mapping relationship between light field information and the measurement position includes: adjusting the distance between the metasurface chip and the light field distribution used for testing to obtain a mapping relationship between the light field information and the measurement position when the distance between the metasurface chip and the light field distribution used for testing changes and the distance between the measurement position and the metasurface chip remains unchanged; and adjusting the distance between the metasurface chip and the measurement position to obtain a mapping relationship between the light field information and the measurement position when the distance between the metasurface chip and the light field distribution used for testing remains unchanged.

[0015] According to another aspect of the present application, the present application provides a light field distribution testing device for a multi-wavelength optical diffraction metasurface chip, including a receiving module, a processing module, a conveying module, a testing module and a computing module, wherein the receiving module receives lasers of multiple bands; the processing module processes lasers of multiple bands to obtain the light field distribution used for testing; the conveying module loads the light field distribution used for testing onto the metasurface chip to obtain the diffraction light field distribution after passing through the metasurface chip; the testing module measures the diffraction light field distribution to obtain the light field information of the focal plane where the measurement position is located; and the computing module adjusts the measurement position to obtain the mapping relationship between the light field information and the measurement position.

[0016] According to some embodiments of the present application, the processing module includes a filtering unit, a collimating and expanding unit, a beam splitting unit, a detection unit and a modulation unit. The filtering unit filters lasers of multiple bands based on a preset wavelength value to obtain an initial laser; the collimating and expanding unit adjusts the spot size and divergence angle of the initial laser to obtain a target laser; the beam splitting unit splits the target laser to obtain a first laser and a second laser; the detection unit measures the wavelength and half-width parameters of the first laser; and the modulation unit modulates the phase of the second laser to obtain the light field distribution used for testing.

[0017] According to another aspect of the present application, an electronic device is provided. The electronic device includes: one or more processors; and a storage device for storing one or more programs. When the one or more programs are executed by the one or more processors, the one or more processors are enabled to implement the light field distribution testing method described above.

[0018] According to another aspect of the present application, a non-volatile computer-readable storage medium is provided, wherein a computer program is stored on the storage medium, and when the computer program is executed by a processor, the light field distribution test method described above can be implemented.

[0019] According to another aspect of the present application, a computer program product is provided. The computer program product includes: a computer program stored on a computer-readable storage medium; the computer program includes program instructions, which, when executed by a computer, cause the computer to perform the light field distribution testing method described above.

[0020] Beneficial technical effects:

[0021] This application receives lasers of multiple wavelengths, processes lasers of multiple wavelengths based on different preset requirements, and obtains lasers of different specific wavelengths, thus breaking through the limitations of traditional single wavelength testing. This application can generate a dynamically adjustable light field distribution for testing based on lasers of different specific wavelengths, load the light field distribution used for testing onto a metasurface chip, obtain the diffracted light field distribution after passing through the metasurface chip, measure the diffracted light field distribution in real time, obtain the light field information of the focal plane where the measurement position is located, and establish a mapping relationship between the light field information and the measurement position by adjusting the measurement position. This can quantitatively characterize the light field distortion law under different propagation distances, and provide an experimental basis for optimizing the hierarchical spacing of optical neural networks. This application also conducts all-round testing of the loaded wavelength, output light field distribution, and diffracted light field distribution of the metasurface, thereby realizing the detection of multiple wavelengths, arbitrary image input, and precise diffraction distance, accurately characterizing the function of the metasurface, and thus improving the testing efficiency of the metasurface chip. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0023] Figure 1 A schematic diagram showing a flow chart of a light field distribution testing method according to an embodiment of the present application;

[0024] Figure 2 Another schematic diagram showing a flow chart of the light field distribution testing method according to an embodiment of the present application;

[0025] Figure 3 Another schematic diagram showing a flow chart of the light field distribution testing method according to an embodiment of the present application;

[0026] Figure 4 Another schematic diagram showing a flow chart of the light field distribution testing method according to an embodiment of the present application;

[0027] Figure 5 Another schematic diagram showing a flow chart of the light field distribution testing method according to an embodiment of the present application;

[0028] Figure 6 Another schematic diagram showing a flow chart of the light field distribution testing method according to an embodiment of the present application;

[0029] Figure 7 Another schematic diagram showing a flow chart of the light field distribution testing method according to an embodiment of the present application;

[0030] Figure 8 Another schematic diagram showing a flow chart of the light field distribution testing method according to an embodiment of the present application;

[0031] Figure 9 A schematic structural diagram of a light field distribution testing device according to an embodiment of the present application is shown;

[0032] Figure 10 A schematic diagram showing the structure of a processing module according to an embodiment of the present application is shown;

[0033] Figure 11 A schematic diagram of the optical path of the light field distribution testing device according to an embodiment of the present application is shown.

[0034] Description of reference numerals:

[0035] Light field distribution testing device 10;

[0036] Receiving module 11;

[0037] Processing module 12; filtering unit 121; collimating and beam expanding unit 122; beam splitting unit 123; detection unit 124; modulation unit 125;

[0038] Conveying module 13; ‌4f system 131; first lens 1311; second lens 1312;

[0039] Testing module 14; objective lens 141; tube lens 142;

[0040] Computing module 15 ; detector 151 ; first translation stage 152 ; second translation stage 153 . DETAILED DESCRIPTION

[0041] Example embodiments will now be described more fully with reference to the accompanying drawings. However, example embodiments can be embodied in many forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete and will fully convey the concepts of the example embodiments to those skilled in the art. Like reference numerals in the drawings represent like or similar parts, and thus repetitive description thereof will be omitted.

[0042] The described features, structures or characteristics may be combined in any suitable manner in one or more embodiments. In the following description, many specific details are provided to provide a full understanding of the embodiments of the present disclosure. However, those skilled in the art will appreciate that the technical solutions of the present disclosure may be practiced without one or more of these specific details, or other methods, components, materials, devices, etc. may be employed. In these cases, well-known structures, methods, devices, implementations, materials or operations will not be shown or described in detail.

[0043] Furthermore, the terms "include," "comprise," and "have," and any variations thereof, are intended to cover non-exclusive inclusions. For example, a process, method, system, product, or apparatus comprising a series of steps or elements is not limited to the listed steps or elements, but may optionally include steps or elements not listed, or may optionally include other steps or elements inherent to the process, method, product, or apparatus.

[0044] The terms "first", "second" and the like in the specification, claims and drawings of this application are used to distinguish different objects rather than to describe a specific order.

[0045] The following is a clear and complete description of the technical solution of this application in conjunction with the drawings in the embodiments of this application. Obviously, the embodiments described are part of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without making any creative efforts are within the scope of protection of this application.

[0046] According to one aspect of the present application, the present application provides a light field distribution testing method for a multi-wavelength optical diffraction metasurface chip. Figure 1 A flow chart of the light field distribution test method according to an embodiment of the present application is shown. Figure 1 As shown, the light field distribution testing method includes steps S100-S500.

[0047] Exemplarily, the light field distribution testing method may be performed by a light field distribution testing device having computing capabilities.

[0048] According to an example embodiment, in step S100 , a light field distribution testing apparatus receives laser light of multiple wavelength bands.

[0049] Lasers with multiple wavelengths can be generated by a laser. For example, the lasers with multiple wavelengths can include visible light or near-infrared wavelengths. The specific lasers with multiple wavelengths can be adaptively selected based on experimental needs.

[0050] Illustratively, the laser may be a wide-band laser or a laser with multiple fixed wavelengths to generate lasers in multiple bands, which is not limited in this application.

[0051] Through the above-mentioned embodiments, this application uses broadband lasers or combined multi-wavelength lasers to generate visible or near-infrared light, covering the typical operating range of metasurface chips. This enables this application to support cross-wavelength light field distribution testing, thereby expanding the test band range.

[0052] Figure 2 Another schematic diagram showing a flow chart of the light field distribution testing method according to an embodiment of the present application; Figure 3Another schematic diagram showing a flow chart of the light field distribution testing method according to an embodiment of the present application; Figure 4 Another schematic diagram showing a flow chart of the light field distribution testing method according to an embodiment of the present application; Figure 5 Another schematic diagram showing a flow chart of the light field distribution testing method according to an embodiment of the present application; Figure 6 Another flow chart of the light field distribution testing method according to an embodiment of the present application is shown.

[0053] According to an example embodiment, in step S200 , the light field distribution testing apparatus processes laser light of multiple wavelength bands to obtain a light field distribution used for testing.

[0054] For example, a light field distribution test device processes lasers of multiple wavelengths through multiple stages to produce a target laser. The target laser is then split into a first laser and a second laser. The light field distribution test device measures the parameters of the first laser to determine whether the wavelength of the selected laser matches the preset experimental value. If so, the second laser is modulated. This modulation of the second laser produces the light field distribution used in the test.

[0055] Alternatively, as Figure 2 As shown, step S200 may further include steps S210-S250.

[0056] In step S210 , the light field distribution testing apparatus pre-processes lasers of multiple wavelength bands to obtain initial lasers.

[0057] For example, the pre-processing may be a filtering operation to select the initial laser light of a specific wavelength required for the experiment.

[0058] In step S220 , the light field distribution testing device processes the initial laser light a second time to obtain the target laser light.

[0059] For example, the secondary processing is a collimation and beam expansion operation to adjust the parameters of the initial laser required for the experiment to produce the target laser.

[0060] In step S230 , the light field distribution testing device splits the target laser to obtain a first laser and a second laser.

[0061] For example, the light field distribution test device uses a beam splitter to split the target laser beam. The beam splitter transmits the horizontally polarized component of the target laser directly, preserving the original beam directionality, to produce the first laser beam. The vertically polarized component of the target laser beam is then reflected to another optical path, producing the second laser beam.

[0062] It should be noted that when the target laser is incident perpendicularly to the dichroic prism, the first laser is transmitted laser light and the second laser light is reflected laser light. When the target laser is incident at an acute angle to the dichroic prism, the second laser light is transmitted laser light and the first laser light is reflected laser light.

[0063] In step S240 , the light field distribution testing device measures the first laser to obtain parameter information of the first laser.

[0064] For example, the parameter information includes at least a wavelength parameter and a half-width parameter, and the first laser can be detected by a spectrum detector to obtain the parameter information.

[0065] In step S250 , when the light field distribution testing device confirms that the parameter information is the same as the preset experimental value, it modulates the second laser to obtain the light field distribution used for testing.

[0066] For example, the wavelength parameter in the preset experimental value may be 532±0.2 nm, and the half-width parameter may be ≤0.5 nm. The light field distribution test device modulates the second laser through an SLM (Spatial Light Modulator).

[0067] For example, the light field distribution test device can also adjust the angle between the incident and output light paths according to the light field distribution device used for different loading tests through a DMD (Digital Micro-mirror Device).

[0068] For example, if we load an 8-bit depth grayscale image, the grayscale matrix to be loaded contains 256 values (0-255). The distribution of these values corresponds to the intensity distribution of the grayscale image, which in turn corresponds to the phase modulation values (0-2π) of the liquid crystal cell on the phase-mode SLM. The required intensity value is determined by the correspondence between the values loaded on the SLM and the reflected light intensity.

[0069] Two polarization modulation elements (polarizers) can be added to the incident and outgoing light paths of the SLM, respectively, so that the polarization direction of the incident light is perpendicular to the outgoing direction after reflection from the SLM, and the polarization direction of the incident light forms a certain angle with the long axis of the liquid crystal molecules in the SLM. A 0-255 identical digital matrix is loaded onto the SLM. By collecting the intensity of the light reflected from the SLM, a correspondence between the loaded value and the intensity is obtained. The light intensity distribution of the image to be tested is modified according to this correspondence to obtain the distribution matrix to be loaded on the SLM. By loading the obtained distribution matrix onto the SLM, the light intensity distribution of the desired image can be obtained, which is the light field distribution.

[0070] Through the above embodiments, the present application can obtain an initial laser by pre-processing lasers of multiple wavelengths, and obtain a target laser by secondary processing the initial laser. The present application can obtain parameter information of the target laser by measuring the target laser, and modulate the target laser based on the parameter information of the target laser being the same as the preset experimental value to obtain the light field distribution used for testing. In this way, an accurate light field distribution used for testing can be obtained, which can easily improve the test accuracy of the metasurface chip.

[0071] Alternatively, as Figure 3 As shown, step S210 may further include step S211.

[0072] In step S211 , the light field distribution testing device filters lasers of multiple wavelength bands based on a preset wavelength value to obtain initial lasers.

[0073] For example, the light field distribution test device can filter lasers of multiple wavelengths using filters. The preset wavelength value can be any value in the visible light or near-infrared band. Filters include, but are not limited to, liquid crystal tunable filters, acousto-optic tunable filters, or optical filters.

[0074] In the case of an acousto-optic tunable filter (AOTF), the optical field distribution test device inputs the target wavelength parameters through an electronically controlled drive module. The AOTF selects a specific wavelength band based on acousto-optic diffraction, suppresses non-target wavelength components, and outputs an initial laser of a single wavelength.

[0075] In the case of a liquid crystal tunable filter, the light field distribution test device inputs the target wavelength parameters through the electronically controlled drive module. The liquid crystal tunable filter selects a specific wavelength band based on the birefringence effect of liquid crystal, suppresses non-target wavelength components, and outputs an initial laser of a single wavelength.

[0076] In the case of an optical filter, the light field distribution test device inputs the target wavelength parameters through the electronically controlled drive module. The optical filter selectively transmits specific wavelengths based on physical coating, selects a specific wavelength band, suppresses non-target wavelength components, and outputs a single wavelength initial laser.

[0077] Through the above-mentioned embodiments, the present application can meet the sensitivity requirements of metasurface chips to incident wavelengths through wavelength screening. This application can achieve rapid multi-wavelength switching through electronically controlled filtering, adapt to complex testing scenarios, and ensure long-term stability in high-power, multimodal environments through the coordinated design of optical filtering and electronic control.

[0078] Alternatively, as Figure 4 As shown, step S220 includes step S221.

[0079] In step S221 , the light field distribution testing device adjusts the spot size and divergence angle of the initial laser to obtain the target laser.

[0080] For example, the light field distribution test device expands and collimates the initial laser beam through a beam expansion system, which includes but is not limited to a wide-band beam expander and a lens assembly.

[0081] When the beam expansion system is a beam expander, a reflective beam expander is further selected, and a concave primary mirror and a convex secondary mirror are selected for off-axis reflection. The concave primary mirror focuses the incident light beam, and the convex secondary mirror re-collimates and enlarges the spot diameter.

[0082] For example, the curvature radius of the concave primary mirror is R1=200mm, the curvature radius of the convex secondary mirror is R2=1000mm, the beam expansion ratio is M=R2 / R1=5, and the concave primary mirror and the convex secondary mirror can expand the diameter of the initial laser from 2mm to 10mm, and control the divergence angle from 1mrad to 0.2mrad, and output the target laser.

[0083] When the beam expansion system is a lens group, a coaxially placed negative lens and a positive lens can be selected. The negative lens diverges the incident light beam, and the positive lens re-collimates and enlarges the spot diameter. By adjusting the distance between the two lenses, the spot diameter and divergence angle of the initial laser can be changed.

[0084] For example, the focal length of the negative lens is f1 = -25 mm, the focal length of the positive lens is f2 = 100 mm, and the distance is d = f2 - f1. The diameter of the initial laser beam is expanded from 2 mm to 8 mm. The divergence angle is controlled to decrease from 3 mrad to 0.5 mrad, and the target laser beam is output.

[0085] Through the above embodiments, the present application can improve the beam quality by efficiently adjusting the spot diameter and divergence angle of the initial laser, thereby providing highly collimated and low-noise laser input, thereby easily improving the accuracy of the detection results.

[0086] Optionally, when the parameter information is a wavelength parameter, such as Figure 5 As shown, step S240 may include steps S241-S242.

[0087] In step S241 , the light field distribution testing apparatus decomposes the first laser to obtain discrete wavelength components.

[0088] For example, the diffraction grating in the spectrum detector decomposes the first laser light into discrete wavelength components through the relationship between the grating constant and the incident angle.

[0089] In step S242 , the light field distribution testing device measures discrete wavelength components to obtain wavelength parameters of the first laser.

[0090] For example, the light field distribution test device can use a CCD sensor or a CMOS sensor. For example, the CCD sensor detects the peak position of discrete wavelength components through an array and calculates the wavelength value based on a calibration curve (such as the characteristic spectrum of a mercury lamp).

[0091] Optionally, when the parameter information is a wavelength parameter, such as Figure 6 As shown, step S240 may further include steps S243-S244.

[0092] In step S243 , the light field distribution testing device separates adjacent wavelengths of the first laser to obtain discrete monochromatic spectral lines.

[0093] For example, a Fabry-Perot interferometer can be used as a light field distribution test device. This instrument separates adjacent wavelengths through multi-beam interference, generating narrowband monochromatic spectral lines. The free spectral range and finesse determine the resolution, resulting in discrete monochromatic spectral lines.

[0094] In step S244 , the light field distribution testing device measures discrete monochromatic spectral lines to obtain a half-width (FWHM) parameter of the first laser.

[0095] For example, the light field distribution test device can directly measure the spectral line information of the laser through a spectrometer and read the wavelength and half-width values.

[0096] Through the above embodiments, the present application can generate reference parameters by measuring the first laser. The present application can also calibrate the initial laser using the reference parameters, thereby easily improving measurement efficiency and accuracy.

[0097] Figure 7 Another flow chart of the light field distribution testing method in an embodiment of the present application is shown.

[0098] In step S300, the light field distribution testing device loads the light field distribution used for testing onto the metasurface chip to obtain the diffracted light field distribution after passing through the metasurface chip.

[0099] For example, the light field distribution used in the test can be transmitted again through a beam splitter prism and then readjusted through the ‌4f system to meet the incident requirements of the metasurface chip to obtain the largest test coverage.

[0100] Optional, such as Figure 7 As shown, step S300 includes S310-S320.

[0101] In step S310 , the light field distribution testing apparatus adjusts the shape of the light field distribution used for testing to obtain a target light field distribution.

[0102] For example, a convex lens with a first lens of f3 and a second lens of f4 focal lengths is used to form a ‌4f system‌, and the size of the light field distribution used in the test is adjusted to obtain a target light field distribution that matches the size of the metasurface chip.‌

[0103] In step S320, the light field distribution testing device loads the target light field distribution onto the metasurface chip to obtain the diffraction light field distribution.

[0104] Through the above embodiments, the present application can adjust the size of the light field distribution used in the test to match the size of the metasurface chip, ensuring that the light field incident on the metasurface chip is consistent with the loaded light field distribution, thereby reducing the experimental error.

[0105] In step S400 , the light field distribution testing device measures the diffracted light field distribution to obtain light field information of a focal plane at a measurement position.

[0106] Exemplarily, the light field distribution testing device measures the diffracted light field distribution through an objective lens, a tube lens, and a detector. The light field information of the focal plane at the measurement position is the laser intensity of the diffracted light field.

[0107] For example, the detector can be a CCD camera or an sCMOS camera.

[0108] For example, by forming an observation module with an objective lens, a tube lens and a CCD camera, the light field distribution information of the focal plane of the objective lens can be observed.

[0109] Through the above embodiments, the present application can amplify the diffracted light field to ensure that the light intensity distribution on the detector receiving surface is not distorted. In addition, the present application can accurately test the diffracted light field distribution after passing through the metasurface chip through high-resolution imaging.

[0110] Figure 8 Another flow chart of the light field distribution testing method in an embodiment of the present application is shown.

[0111] In step S500 , the light field distribution testing apparatus adjusts the measurement position to obtain a mapping relationship between light field information and the measurement position.

[0112] For example, the measurement position can be adjusted by the first translation stage and the second translation stage.

[0113] The light field distribution test device uses a first translation stage to adjust the position of the metasurface chip, changing the distance between the metasurface chip and the light field distribution used for testing, to obtain the diffracted light field distribution at different distances. The light field distribution test device also uses a second translation stage to adjust the test distance, to obtain the laser intensity at different test distances.

[0114] Optional, such as Figure 8 As shown, step S500 includes S510-S520.

[0115] In step S510, when the distance between the metasurface chip and the light field distribution used for testing changes and the distance between the measurement position and the metasurface chip remains unchanged, the light field distribution testing device adjusts the distance between the metasurface chip and the light field distribution used for testing to obtain a mapping relationship between the light field information and the measurement position.

[0116] For example, the first translation stage drives the metasurface chip to translate along the optical axis, while the second translation stage simultaneously drives the objective lens to maintain a constant distance between the metasurface chip and the objective lens. The first and second translation stages are used to change the distance between the metasurface chip and the light field distribution used for testing. A detector measures the light field distribution at the focal plane of the objective lens and records the light field distribution at different distances via a connected computer. The translation stage coordinates are correlated with the corresponding light field distribution to obtain a mapping between the light field information and the measurement position.

[0117] In step S520, when the distance between the metasurface chip and the light field distribution used for testing remains unchanged, the light field distribution testing device adjusts the distance between the metasurface chip and the measurement position to obtain a mapping relationship between the light field information and the measurement position.

[0118] For example, under the condition that the distance between the metasurface chip and the light field distribution used for testing remains unchanged, the second translation stage drives the objective lens to translate along the optical axis, and the detector measures the light field distribution of the focal plane at different distances from the objective lens to obtain the mapping relationship between the light field information and the measurement position.

[0119] Through the above embodiments, the present application can realize the light field distribution detection of precise diffraction distance by observing the light field information of the focal plane position at different distances, thereby improving the testing efficiency of the metasurface chip.

[0120] Figure 9 A schematic structural diagram of a light field distribution testing device according to an embodiment of the present application is shown; Figure 10 A schematic diagram showing the structure of a processing module according to an embodiment of the present application is shown; Figure 11 A schematic diagram of the optical path of the light field distribution testing device according to an embodiment of the present application is shown.

[0121] According to another aspect of the present application, the present application provides a multi-wavelength optical diffraction metasurface chip light field distribution testing device. Figure 9 As shown, the light field distribution testing device 10 includes a receiving module 11 , a processing module 12 , a delivery module 13 , a testing module 14 and a computing module 15 .

[0122] According to an example embodiment, the receiving module 11 receives laser light of multiple wavelength bands.

[0123] Lasers with multiple wavelengths can be generated by a laser. For example, the lasers with multiple wavelengths can include visible light or near-infrared wavelengths. The specific lasers with multiple wavelengths can be adaptively selected based on experimental needs.

[0124] Illustratively, the laser may be a wide-band laser or a laser with multiple fixed wavelengths to generate lasers in multiple bands, which is not limited in this application.

[0125] Through the above-mentioned embodiments, this application uses broadband lasers or combined multi-wavelength lasers to generate visible or near-infrared light, covering the typical operating range of metasurface chips. This enables this application to support cross-wavelength light field distribution testing, thereby expanding the test band range.

[0126] According to an exemplary embodiment, the processing module 12 processes laser light of multiple wavelength bands to obtain a light field distribution used for testing.

[0127] For example, processing module 12 processes lasers of multiple wavelengths through multiple stages to obtain a target laser. The target laser is then split into a first laser and a second laser. Processing module 12 measures the parameters of the first laser to determine whether the wavelength of the selected laser matches the preset experimental value. If so, it modulates the second laser. This modulation of the second laser produces the light field distribution used in the test.

[0128] Optionally, the processing module 12 pre-processes lasers of multiple wavelength bands to obtain initial lasers.

[0129] For example, the pre-processing may be a filtering operation to select the initial laser light of a specific wavelength required for the experiment.

[0130] Optionally, the processing module 12 processes the initial laser light a second time to obtain the target laser light.

[0131] For example, the secondary processing is a collimation and beam expansion operation to adjust the parameters of the initial laser required for the experiment to produce the target laser.

[0132] Optionally, the processing module 12 splits the target laser to obtain a first laser and a second laser.

[0133] For example, the processing module 12 splits the target laser beam using a beam splitter prism. The beam splitter prism can directly transmit the horizontally polarized component of the target laser beam, preserving the original beam directionality, to produce the first laser beam. The vertically polarized component of the target laser beam is reflected to another optical path to produce the second laser beam.

[0134] It should be noted that when the target laser is incident perpendicularly to the dichroic prism, the first laser is transmitted laser light and the second laser light is reflected laser light. When the target laser is incident at an acute angle to the dichroic prism, the second laser light is transmitted laser light and the first laser light is reflected laser light.

[0135] Optionally, the processing module 12 measures the first laser to obtain parameter information of the first laser.

[0136] For example, the parameter information includes at least a wavelength parameter and a half-width parameter, and the first laser can be detected by a spectrum detector to obtain the parameter information.

[0137] Optionally, when the processing module 12 confirms that the parameter information is the same as the preset experimental value, it modulates the second laser to obtain a light field distribution used for testing.

[0138] For example, the wavelength parameter in the preset experimental value may be 532±0.2 nm, and the half-width parameter may be ≤0.5 nm. The processing module 12 modulates the second laser light through an SLM (Spatial Light Modulator).

[0139] For example, the processing module 12 may also adjust the angle between the incident and outgoing light paths according to devices with light field distributions used in different loading tests through a DMD (Digital Micro-mirror Device).

[0140] For example, if we load an 8-bit depth grayscale image, the grayscale matrix to be loaded contains 256 values (0-255). The distribution of these values corresponds to the intensity distribution of the grayscale image, which in turn corresponds to the phase modulation values (0-2π) of the liquid crystal cell on the phase-mode SLM. The required intensity value is determined by the correspondence between the values loaded on the SLM and the reflected light intensity.

[0141] Two polarization modulation elements (polarizers) can be added to the incident and outgoing light paths of the SLM, respectively, so that the polarization direction of the incident light is perpendicular to the outgoing direction after reflection from the SLM, and the polarization direction of the incident light forms a certain angle with the long axis of the liquid crystal molecules in the SLM. A 0-255 identical digital matrix is loaded onto the SLM. By collecting the intensity of the light reflected from the SLM, a correspondence between the loaded value and the intensity is obtained. The light intensity distribution of the image to be tested is modified according to this correspondence to obtain the distribution matrix to be loaded on the SLM. By loading the obtained distribution matrix onto the SLM, the light intensity distribution of the desired image can be obtained, which is the light field distribution.

[0142] Through the above embodiments, the present application can obtain an initial laser by pre-processing lasers of multiple wavelengths, and obtain a target laser by secondary processing the initial laser. The present application can obtain parameter information of the target laser by measuring the target laser, and modulate the target laser based on the parameter information of the target laser being the same as the preset experimental value to obtain the light field distribution used for testing. In this way, an accurate light field distribution used for testing can be obtained, which can easily improve the test accuracy of the metasurface chip.

[0143] Alternatively, as Figure 10 As shown, the processing module 12 includes a filtering unit 121 , a collimating and beam expanding unit 122 , a beam splitting unit 123 , a detection unit 124 and a modulation unit 125 .

[0144] like Figure 11 As shown, the filtering unit 121, the collimating and beam expanding unit 122, the beam splitting unit 123 and the detection unit 124 are sequentially arranged in a direction away from the receiving module 11. The modulation unit 125 is located on one side of the beam splitting unit 123. The angle between the line connecting the collimating and beam expanding unit 122 and the beam splitting unit 123 and the line connecting the beam splitting unit 123 and the detection unit 124 is , .

[0145] Optionally, the filtering unit 121 filters lasers of multiple wavelength bands based on a preset wavelength value to obtain initial lasers.

[0146] For example, the filtering unit 121 can filter lasers of multiple wavelengths using filters. The preset wavelength value can be any value in the visible light or near-infrared band. The filter includes but is not limited to a liquid crystal tunable filter, an acousto-optic tunable filter, or an optical filter.

[0147] In the case of an acousto-optic tunable filter (AOTF), the filter unit 121 inputs the target wavelength parameters via the electronically controlled drive module. The AOTF selects a specific wavelength band based on acousto-optic diffraction, suppresses non-target wavelength components, and outputs an initial laser of a single wavelength.

[0148] In the case of a liquid crystal tunable filter, the filter unit 121 inputs the target wavelength parameters through the electronically controlled drive module. The liquid crystal tunable filter selects a specific wavelength band based on the birefringence effect of liquid crystal, suppresses non-target wavelength components, and outputs a single wavelength initial laser.

[0149] In the case of an optical filter, the filter unit 121 inputs the target wavelength parameters through the electronic control drive module. The optical filter selects a specific wavelength band based on the physical coating to selectively transmit specific wavelengths, suppresses non-target wavelength components, and outputs a single wavelength initial laser.

[0150] Through the above-mentioned embodiments, the present application can meet the sensitivity requirements of metasurface chips to incident wavelengths through wavelength screening. This application can achieve rapid multi-wavelength switching through electronically controlled filtering, adapt to complex testing scenarios, and ensure long-term stability in high-power, multimodal environments through the coordinated design of optical filtering and electronic control.

[0151] Optionally, the collimating and beam expanding unit 122 adjusts the spot size and divergence angle of the initial laser to obtain the target laser.

[0152] For example, the collimating and beam expanding unit 122 expands and collimates the initial laser beam through a beam expanding system, which includes but is not limited to a wide-band beam expander and a lens group.

[0153] When the beam expansion system is a beam expander, a reflective beam expander is further selected, and a concave primary mirror and a convex secondary mirror are selected for off-axis reflection. The concave primary mirror focuses the incident light beam, and the convex secondary mirror re-collimates and enlarges the spot diameter.

[0154] For example, the curvature radius of the concave primary mirror is R1=200mm, the curvature radius of the convex secondary mirror is R2=1000mm, the beam expansion ratio is M=R2 / R1=5, and the concave primary mirror and the convex secondary mirror can expand the diameter of the initial laser from 2mm to 10mm, and control the divergence angle from 1mrad to 0.2mrad, and output the target laser.

[0155] When the beam expansion system is a lens group, a coaxially placed negative lens and a positive lens can be selected. The negative lens diverges the incident light beam, and the positive lens re-collimates and enlarges the spot diameter. By adjusting the distance between the two lenses, the spot diameter and divergence angle of the initial laser can be changed.

[0156] For example, the focal length of the negative lens is f1 = -25 mm, the focal length of the positive lens is f2 = 100 mm, and the distance is d = f2 - f1. The diameter of the initial laser beam is expanded from 2 mm to 8 mm. The divergence angle is controlled to decrease from 3 mrad to 0.5 mrad, and the target laser beam is output.

[0157] Through the above embodiments, the present application can improve the beam quality by efficiently adjusting the spot diameter and divergence angle of the initial laser, thereby providing highly collimated and low-noise laser input, thereby easily improving the accuracy of the detection results.

[0158] Optionally, the beam splitting unit 123 splits the target laser light to obtain the first laser light and the second laser light.

[0159] Optionally, when the parameter information is a wavelength parameter, the detection unit 124 decomposes the first laser to obtain discrete wavelength components.

[0160] For example, the diffraction grating in the spectrum detector decomposes the first laser light into discrete wavelength components through the relationship between the grating constant and the incident angle.

[0161] The detection unit 124 measures the discrete wavelength components to obtain the wavelength parameters of the first laser.

[0162] For example, the detection unit 124 may be a CCD sensor or a CMOS sensor. For example, the CCD sensor detects the peak position of discrete wavelength components through an array and calculates the wavelength value in combination with a calibration curve (such as a mercury lamp characteristic spectrum).

[0163] Optionally, when the parameter information is a wavelength parameter, the detection unit 124 separates adjacent wavelengths of the first laser to obtain discrete monochromatic spectral lines.

[0164] For example, the detection unit 124 may use a Fabry-Perot interferometer. The Fabry-Perot interferometer separates adjacent wavelengths through multi-beam interference to produce narrow-band monochromatic spectral lines. The free spectral range and fineness determine the resolution, resulting in discrete monochromatic spectral lines.

[0165] The detection unit 124 measures the discrete monochromatic spectral lines to obtain the half-maximum width parameter of the first laser.

[0166] For example, the detection unit 124 can directly measure the spectrum line information of the laser through a spectrometer and read the wavelength and half-maximum width.

[0167] Through the above embodiments, the present application can generate reference parameters by measuring the first laser. The present application can also calibrate the initial laser using the reference parameters, thereby easily improving measurement efficiency and accuracy.

[0168] According to an exemplary embodiment, the delivery module 13 loads the light field distribution used for the test onto the metasurface chip to obtain a diffracted light field distribution after passing through the metasurface chip.

[0169] For example, the light field distribution used in the test can be transmitted again through a beam splitter prism and then readjusted through the ‌4f system to meet the incident requirements of the metasurface chip to obtain the largest test coverage.

[0170] Optionally, the delivery module 13 adjusts the shape of the light field distribution used for the test to obtain a target light field distribution.

[0171] For example, a convex lens with a first lens of f3 and a second lens of f4 focal lengths is used to form a ‌4f system‌, and the size of the light field distribution used in the test is adjusted to obtain a target light field distribution that matches the size of the metasurface chip.‌

[0172] Optionally, the delivery module 13 loads the target light field distribution onto the metasurface chip to obtain a diffracted light field distribution.

[0173] Through the above embodiments, the present application can adjust the size of the light field distribution used in the test to match the size of the metasurface chip, ensuring that the light field incident on the metasurface chip is consistent with the loaded light field distribution, thereby reducing the experimental error.

[0174] According to an exemplary embodiment, the testing module 14 measures the diffracted light field distribution to obtain light field information of a focal plane where the measurement position is located.

[0175] Exemplarily, the testing module 14 measures the diffracted light field distribution through the objective lens 141, the tube lens 142, and the detector 151. The light field information of the focal plane at the measurement position is the laser intensity of the diffracted light field.

[0176] For example, the detector 151 may be a CCD camera or an sCMOS camera.

[0177] For example, the objective lens 141 , the tube lens 142 and the CCD camera form an observation module, and the light field distribution information of the focal plane of the objective lens can be observed.

[0178] Through the above embodiments, the present application can amplify the diffracted light field to ensure that the light intensity distribution on the detector receiving surface is not distorted. In addition, the present application can accurately test the diffracted light field distribution after passing through the metasurface chip through high-resolution imaging.

[0179] According to an example embodiment, the calculation module 15 adjusts the measurement position to obtain a mapping relationship between the light field information and the measurement position.

[0180] For example, the measurement position may be adjusted by the first translation stage 152 and the second translation stage 153 .

[0181] The calculation module 15 adjusts the position of the metasurface chip using the first translation stage, changing the distance between the metasurface chip and the light field distribution used for testing, thereby obtaining the diffracted light field distribution at different distances. The calculation module 15 adjusts the test distance using the second translation stage, thereby obtaining the laser intensity at different test distances.

[0182] Optionally, when the distance between the metasurface chip and the light field distribution used for testing changes and the distance between the measurement position and the metasurface chip remains unchanged, the calculation module 15 adjusts the distance between the metasurface chip and the light field distribution used for testing to obtain a mapping relationship between the light field information and the measurement position.

[0183] For example, the first translation stage 152 drives the metasurface chip to translate along the optical axis, while the second translation stage 153 drives the objective lens 141 to move synchronously, maintaining a constant distance between the metasurface chip and the objective lens 141. The first and second translation stages 152, 153 are used to change the distance between the metasurface chip and the light field distribution used for testing. The detector 151 measures the light field distribution at the focal plane of the objective lens 141 and records the light field distribution at different distances via a connected computer. The translation stage coordinates are associated with the corresponding light field distribution to obtain a mapping relationship between the light field information and the measurement position.

[0184] Optionally, when the distance between the metasurface chip and the light field distribution used for testing remains unchanged, the calculation module 15 adjusts the distance between the metasurface chip and the measurement position to obtain a mapping relationship between the light field information and the measurement position.

[0185] For example, under the condition that the distance between the metasurface chip and the light field distribution used for testing remains unchanged, the second translation stage 153 drives the objective lens 141 to translate along the optical axis, and the detector 151 measures the light field distribution of the focal plane at different distances from the objective lens 141 to obtain a mapping relationship between the light field information and the measurement position.

[0186] Through the above embodiments, the present application can realize the light field distribution detection of precise diffraction distance by observing the light field information of the focal plane position at different distances, thereby improving the testing efficiency of the metasurface chip.

[0187] According to one aspect of the present application, an electronic device is provided. The electronic device includes: one or more processors; and a storage device for storing one or more programs, which, when executed by the one or more processors, enables the one or more processors to implement the light field distribution testing method described above.

[0188] According to one aspect of the present application, the present application further provides a non-volatile computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, can implement the light field distribution testing method described above.

[0189] Finally, it should be noted that the above description is merely a preferred embodiment of the present application and is not intended to limit the present application. Although the present application is described in detail with reference to the aforementioned embodiments, those skilled in the art will be able to modify the technical solutions of the aforementioned embodiments or replace some of the technical features therein with equivalents. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present application shall be included within the scope of protection of the present application.

Claims

1. A method for testing the light field distribution of a multi-wavelength optical diffraction metasurface chip, characterized in that: include: Receive lasers in multiple wavelength bands; Processing the laser beams of the plurality of wavelength bands to obtain a light field distribution used for testing; Loading the light field distribution used for the test onto the metasurface chip to obtain the diffracted light field distribution after passing through the metasurface chip; Measuring the diffracted light field distribution to obtain light field information of a focal plane at a measurement position; Adjusting the measurement position to obtain a mapping relationship between the light field information and the measurement position; The processing of the laser beams of the plurality of wavelength bands to obtain a light field distribution for testing includes: pre-processing the laser beams of the plurality of wavelength bands to obtain initial laser beams; Secondarily processing the initial laser to obtain a target laser; Splitting the target laser to obtain a first laser and a second laser; measuring the first laser to obtain parameter information of the first laser; When confirming that the parameter information is the same as the preset experimental value, modulating the second laser to obtain the light field distribution used for the test, including modulating the second laser through a spatial light modulator; Adjusting the measurement position includes: changing the distance between the metasurface chip and the light field distribution used for testing through a first translation stage and a second translation stage, wherein the first translation stage is used to drive the metasurface chip to translate along the optical axis, and the second translation stage is used to drive the focal plane of the objective lens to translate along the optical axis.

2. The light field distribution testing method according to claim 1, characterized in that: The pre-processing of the laser beams of the plurality of wavelength bands to obtain the initial laser beams comprises: The laser beams of the plurality of wavelength bands are filtered based on a preset wavelength value to obtain the initial laser beam.

3. The light field distribution testing method according to claim 1, characterized in that: The secondary processing of the initial laser to obtain the target laser comprises: The spot size and divergence angle of the initial laser are adjusted to obtain the target laser.

4. The light field distribution testing method according to claim 1, characterized in that: The parameter information includes a wavelength parameter, and measuring the first laser to obtain the parameter information of the first laser includes: decomposing the first laser to obtain discrete wavelength components; The discrete wavelength components are measured to obtain the wavelength parameter of the first laser.

5. The light field distribution testing method according to claim 1, characterized in that: The parameter information includes a half-width parameter, and measuring the first laser to obtain the parameter information of the first laser includes: Separating adjacent wavelengths of the first laser to obtain discrete monochromatic spectral lines; The discrete monochromatic spectral line is measured to obtain the half-width parameter of the first laser.

6. The light field distribution testing method according to claim 1, characterized in that: The step of loading the light field distribution used for the test onto the metasurface chip to obtain the diffracted light field distribution after passing through the metasurface chip includes: Adjusting the shape of the light field distribution used in the test to obtain a target light field distribution; The target light field distribution is loaded onto the metasurface chip to obtain the diffracted light field distribution.

7. The light field distribution testing method according to claim 1, characterized in that: The adjusting the measurement position to obtain a mapping relationship between the light field information and the measurement position includes: When the distance between the metasurface chip and the light field distribution used for the test changes and the distance between the measurement position and the metasurface chip remains unchanged, adjusting the distance between the metasurface chip and the light field distribution used for the test to obtain a mapping relationship between the light field information and the measurement position; When the distance between the metasurface chip and the light field distribution used for the test remains unchanged, the distance between the metasurface chip and the measurement position is adjusted to obtain a mapping relationship between the light field information and the measurement position.

8. A light field distribution testing device for a multi-wavelength optical diffraction metasurface chip, wherein the light field distribution testing device performs the light field distribution testing method according to any one of claims 1 to 7, characterized in that: The light field distribution testing device comprises: Receiving module, receiving lasers of multiple bands; A processing module, processing the lasers of the multiple wavelength bands to obtain a light field distribution used for testing; A delivery module, which loads the light field distribution used for the test onto the metasurface chip to obtain a diffracted light field distribution after passing through the metasurface chip; A testing module measures the diffracted light field distribution to obtain light field information of a focal plane at a measurement position; A calculation module adjusts the measurement position to obtain a mapping relationship between the light field information and the measurement position.

9. The light field distribution testing device according to claim 8, characterized in that: The processing module includes: a filtering unit, configured to filter the laser beams of the plurality of wavelength bands based on a preset wavelength value to obtain an initial laser beam; A collimating and beam expanding unit, for adjusting the spot size and divergence angle of the initial laser to obtain a target laser; a beam splitting unit, which splits the target laser to obtain a first laser and a second laser; a detection unit, for measuring the wavelength and half-width of the first laser; A modulation unit modulates the phase of the second laser to obtain the light field distribution used for the test.

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