Optical detection method for metasurface chip

Abstract

A metasurface chip optical detection method comprises the steps of optical detection optical path building machine and concentric shaft adjustment, power-light spot gray scale relation calibration, light spot gray scale collection and fitting analysis in the product optical detection process, light transmittance calculation and divergence angle analysis and comparison judgment. In the process, the power meter senses the optical power of the light emitting side, the CCD camera collects light spot information and converts the light spot information into electrical information, the electrical information is subjected to fitting analysis through the background information processing unit to obtain a linear relation between the two, and then a detection parameter value is calculated according to the linear relation. The detection method provided by the invention is simple in working principle, the detection mode is easy to implement, the detection cost is controllable, the detection efficiency is high, the detection stability is high, the repetition rate is good, and the defect that the characterization judgment capability of the optical performance of the metasurface chip is insufficient in China is effectively overcome.

Description

Technical Field

[0001] The present invention relates to the technical field of chip quality detection, and in particular to a super-surface chip optical detection method and an optical detection device. Background Art

[0002] The metasurface chip is a chip with a layer of metal superlens coated on the surface. The chip consists of three parts: the metasurface layer, the microlens and the image sensor. The metasurface layer is composed of multiple different metasurface units, which have different spectral modulation effects on the incident light; the microlens focuses the modulated light onto the image sensor for detection, and the spectral information of the incident light can be reconstructed from the detected light intensity. Traditional spectral imaging technology generally uses spatial scanning or wavelength scanning mode, and cannot obtain the spectral information of each pixel in the field of view in real time. The snapshot spectral imaging technology solution based on the metasurface can achieve broadband modulation of the incident light spectrum at each point in space by designing metasurface units with different structures, and uses image sensors to collect modulated light signals. The spectral information of the incident light is obtained by computational reconstruction, and the computational spectrometer is spatially arrayed to achieve spectral imaging.

[0003] The metal superlens on the surface of the metasurface chip needs to be quality inspected. The parameters used for performance testing of metal superlenses are also quite different from those of traditional lenses. Traditional lenses mainly judge the performance of the lens by detecting data such as refractive index, transmittance, focal length, and distortion. The structure of superlenses is complex and its performance is affected by many factors. Performance is mainly judged by detecting parameters such as transmittance and scattering angle. Among them, the detection of transmittance requires high precision and is an important parameter to characterize the optical performance of superlenses. There is a lack of superlens transmittance detection methods that can be used for actual production testing in China, which seriously restricts the development of domestic metasurface chips.

[0004] The present invention proposes a super-surface chip optical detection method to solve the above-mentioned technical problems. Summary of the invention

[0005] A method for optical detection of a super-surface chip, the method is as follows: a light source, a super-surface chip, and a photosensitive element are placed at the same optical axis position, the light emitted by the light source passes through the super-surface chip and is received by the photosensitive element and converted into an electrical signal, after data processing of the electrical signal, the optical information of the product is calculated and whether the optical performance of the product is qualified is determined;

[0006] The light transmittance of the metasurface chip is determined by detecting the power on the light side and the grayscale of the image received by the photosensitive element.

[0007] Preferably, the metasurface chip optical detection method determines whether the optical performance is qualified by detecting the transmittance and scattering angle of the metasurface chip.

[0008] Preferably, in the optical detection method of a metasurface chip, the transmittance detection process includes power-spot grayscale calibration, analysis of the image grayscale of the light-emitting side of the metasurface chip, and analysis of the transmittance of the metasurface chip;

[0009] In the power-image grayscale calibration step, the corresponding relationship between the light source power and the light spot grayscale is determined;

[0010] In the step of analyzing the grayscale of the image on the light-emitting side of the metasurface chip, a photosensitive element is used to receive a target light spot from the light-emitting side of the metasurface chip;

[0011] In the step of analyzing the transmittance of the metasurface chip, the grayscale of the target light spot is analyzed and the corresponding relationship between the light source power and the light spot grayscale is used to fit the corresponding relationship between the target light spot and the light output power, thereby calculating the transmittance of the metasurface chip.

[0012] Preferably, the optical detection method of a metasurface chip and the power-spot grayscale calibration method are as follows:

[0013] Use a power meter to detect the power P of the light source 0 ;

[0014] Place the light source, metasurface chip, and power meter on the same optical axis and measure the power P;

[0015] Place the light source, metasurface chip, and photosensitive element on the same optical axis, collect the light spot image, perform grayscale integration on the light spot image, and obtain the grayscale value G;

[0016] By changing the light source power, multiple sets of P and G data are obtained, and the distance from the power meter to the light source and the distance from the power meter to the metasurface chip remain unchanged during the measurement of P and G;

[0017] Among them, the corresponding formulas of P and G are obtained by fitting the experimental data of P and G.

[0018] Preferably, in the optical detection method for a metasurface chip, power-spot grayscale calibration obtains a linear correspondence between power and spot grayscale.

[0019] Preferably, in the optical detection method of a metasurface chip, the collected spot image is first spot fitted and then grayscale integral calculation is performed to fit the spot into an ellipse. The spot fitting technology can adopt the existing technical solution.

[0020] Preferably, in the optical detection method of a metasurface chip, the method for adjusting the coaxial positions of the light source, the metasurface chip, and the photosensitive element is as follows:

[0021] First, one of the light source and the photosensitive element is fixed and placed, and the photosensitive element is used for detection and observation. When the optical image is located at the center of the field of view, it is regarded as a concentric axis.

[0022] The metasurface chip is placed, and detected and observed by a photosensitive element. The metasurface chip is located at the center of the imaging field of the photosensitive element and is regarded as a concentric axis;

[0023] Turn on the light source and adjust the photosensor up and down. If the position of the light spot remains unchanged, then they are on the same optical axis.

[0024] Preferably, in the metasurface chip optical detection method, a power attenuation sheet is provided in front of the photosensitive element during the calibration and detection steps to prevent the photosensitive element from being damaged by excessive light source power.

[0025] The advantages are as follows:

[0026] The metasurface chip optical detection method involved in the present invention uses power-spot grayscale analysis and calculation to obtain transmittance detection data, and successively obtains the power value for judgment through the construction of optical circuits, calibration of power-spot grayscale, collection of product spot grayscale and power calculation. In this process, the divergence angle is calculated according to the data of focal length and long axis of the spot, and the optical performance of the metasurface chip is comprehensively judged by the transmittance and divergence angle.

[0027] This invention patent selects detection parameters in a targeted manner according to the structure and optical characteristics of the superlens, and creatively proposes a detection method for the detection parameters based on the selected detection parameters. The parameter detection method is obtained after advance calibration and repeated verification. The calibration relationship is accurate, the detection stability is high, and the detection repetition rate of a single product is high, which effectively makes up for the domestic shortcomings in the detection of optical properties of metasurface chips. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The specific implementation is further described below in conjunction with the accompanying drawings, wherein:

[0029] Figure 1 , a flow chart of a super-surface chip optical detection method according to the present invention;

[0030] Figure 2 It is a simplified diagram of a power-spot grayscale calibration method in a metasurface chip optical detection method involved in specific implementation case 1;

[0031] Figure 3 It is a scatter plot of the PG relationship corresponding to Table 1;

[0032] Figure 4 Schematic diagram of the light spot collected by the CCD camera;

[0033] The following specific implementation manner will further illustrate the present invention in conjunction with the above-mentioned drawings. DETAILED DESCRIPTION

[0034] Specific implementation case 1:

[0035] In this embodiment, the light source is defined as a laser, and the photosensitive element is defined as a CCD camera. This is only for the purpose of specific description and does not limit the light source and photosensitive element;

[0036] Step1: Use a power meter to detect the power P of the laser 0 ;

[0037] Step2: Place the laser, metasurface chip, and laser power meter on the same optical axis position and measure the power P;

[0038] Step3: Place the laser, metasurface chip, and CCD camera on the same optical axis position. The CCD camera takes a spot image, and performs gray-scale integration on the spot image to obtain the gray-scale value G;

[0039] Step4: By changing the laser power, obtain multiple sets of P and G data, and during the measurement of P and G, the distances from the power meter to the light source and from the power meter to the metasurface chip are respectively the same;

[0040] The above power-spot gray-scale calibration method is as Figure 2 shown. The detection data of multiple sets of P and G are shown in Table 1, and the corresponding scatter plot of Table 1 is as Figure 3 shown; Table 1 P-G detection data

[0041]

[0042] Among them, according to the relationship between P and G, the corresponding formula of P and G is obtained by least squares fitting. Through Table 1 and Figure 3 it can be seen that within the detection error range, the ratio between P and G is a fixed value, so as to obtain the conversion relationship between the spot gray-scale and the power and the fitting degree is very high;

[0043] K = P / G;

[0044] Step5: Place the laser, metasurface chip, and CCD camera on the same optical axis position. The CCD camera captures the spot image on the light-emitting side of the metasurface chip, and performs full-area integration on the collected spot to obtain the gray-scale value G 0 , and obtain the light intensity transmittance

[0045] T = K * G 0 / P 0 ;

[0046] Step6: Integrate the spot gray-scale within the specified divergence angle to obtain the spot gray-scale value G within the specified divergence angle 1 , then the light intensity transmittance within the specified divergence angle

[0047] T 1 = K * G1 / P 0

[0048] If T 1 Or if T is less than the set value, the product transmittance is unqualified.

[0049] The light spot major axis obtained by CCD camera fitting is m, the working distance is d, and the divergence angle is

[0050] A=arctan(m / d). When A is less than the set value, the scattering angle of the product is qualified.

[0051] In order to reversely test the stability of the test results of the above test method, a single product was tested repeatedly according to the above method. The test data are shown in Table 2.

[0052] Table 2 Repeated experimental data of transmittance test of a single metasurface chip

[0053]

[0054] It can be seen from Table 2 that the transmittance detection repeatability in the optical detection process of the metasurface chip (superlens) involved in the present invention is very high, the repetition accuracy error is 0.6%, the repeatability is very high, the detection result is very stable, and it can be used in the field of transmittance detection of superlens optical detection.

[0055] Specific implementation case 2:

[0056] In the specific implementation case 1, the spot fitting is performed before the grayscale integration of the spot image collected by the CCD camera, and the spot is fitted into an ellipse. The spot fitting technology can adopt the existing technical solution.

[0057] Specific implementation case 3:

[0058] In the specific implementation example 1, the method for adjusting the coaxial positions of the laser, the over-surface chip, and the CCD camera is as follows:

[0059] First, one of the light source and the photosensitive element is fixed and placed, and the photosensitive element is used for detection and observation. When the optical image is located at the center of the field of view, it is regarded as a concentric axis.

[0060] The metasurface chip is placed, and detected and observed by a photosensitive element. The metasurface chip is located at the center of the imaging field of the photosensitive element and is regarded as a concentric axis;

[0061] Turn on the laser, adjust the photosensor up and down, and if the position of the light spot remains unchanged, then they are on the same optical axis.

[0062] Optionally, during the calibration and detection steps, a power attenuation sheet is provided in front of the photosensitive element to prevent the CCD camera from being damaged by excessive light source power.

[0063] In specific implementation cases 1 to 3, in order to complete the position adjustment of the coaxial axes of the laser, metasurface chip, and CCD camera more quickly, the calibration sheet can be used to adjust the concentric axis of the metasurface chip. After the calibration sheet is adjusted to the concentric axis position, the chip can be placed in the position of the calibration sheet after the position adjustment. Before detection, turn on the laser, adjust the photosensitive element up and down, and observe whether the spot position changes to determine whether it is a concentric axis.

[0064] The above-mentioned embodiments only express several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the patent of the present invention. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A method for optical detection of metasurface chips, Features: The transmittance is calculated by using the image grayscale of the light-emitting side of the metasurface chip to obtain the corresponding light-emitting side power, and the transmittance of the metasurface chip is obtained.

2. A method for optically detecting a metasurface chip according to claim 1, Features: The optical performance testing of metasurface chips includes transmittance and divergence angle.

3. A method for optical detection of a metasurface chip as claimed in claim 1, Features: The transmittance detection process includes power-spot grayscale calibration, analysis of the image grayscale on the light-emitting side of the metasurface chip, and analysis of the transmittance of the metasurface chip; In the power-image grayscale calibration step, the corresponding relationship between the light source power and the light spot grayscale is determined; In the step of analyzing the grayscale of the image on the light-emitting side of the metasurface chip, a photosensitive element is used to receive a target light spot from the light-emitting side of the metasurface chip; In the step of analyzing the transmittance of the metasurface chip, the grayscale of the target light spot is analyzed, and the corresponding relationship between the target light spot pair and the light output power is fitted using the corresponding relationship between the light source power and the light spot grayscale, and the transmittance of the metasurface chip is calculated.

4. A method for optical detection of a metasurface chip as claimed in claim 3, Features: The operation method of the power-spot grayscale calibration is as follows: Use a power meter to detect the power P of the light source 0 ; Place the light source, metasurface chip, and power meter on the same optical axis and measure the power P; Place the light source, metasurface chip, and photosensitive element on the same optical axis, collect the light spot image, perform grayscale integration on the light spot image, and obtain the grayscale value G; By changing the light source power, multiple sets of P and G data are obtained, and the distance from the power meter to the light source and the distance from the power meter to the metasurface chip remain unchanged during the measurement of P and G; Among them, the corresponding relationship between P and G is obtained by fitting the experimental data of P and G.

5. A method for optical detection of a metasurface chip as claimed in claim 3, Features: The power-spot grayscale calibration obtains a linear correspondence between power and spot grayscale.

6. A method for optical detection of a metasurface chip as claimed in claim 3, Features: The collected spot image is first subjected to spot fitting and then grayscale integral calculation.

7. A method for optical detection of a metasurface chip as claimed in claim 1, Features: During the optical inspection process, the light source, the chip with the over-standard surface, and the photosensitive element are in the concentric axis position. The method for adjusting the concentric axis position is as follows: First, one of the light source and the photosensitive element is fixed and placed, and the photosensitive element is used for detection and observation. When the optical image is located at the center of the field of view, it is regarded as a concentric axis. The metasurface chip is placed and detected and observed through a photosensitive element. The metasurface chip is regarded as a concentric axis after being located at the center of the imaging field of view of the photosensitive element.

8. A method for optical detection of a metasurface chip as claimed in claim 7, Features: After the concentric axis position is adjusted, turn on the light source and adjust the photosensitive element up and down. If the light spot position remains unchanged, then it is the same optical axis.

9. A method for optical detection of a metasurface chip as claimed in claim 3, Features: During the calibration and detection steps, a power attenuation sheet is provided in front of the photosensitive element.

Images