Method for determination of wavelength-resolved goos-hanchen shift and biochemical sensing method based thereon

Abstract

A method for measuring wavelength-resolved Goos-Haunchn shift and a biochemical sensing method based on the same, the method comprising: irradiating incident light from a light source module to a sample on a sample stage, the incident light being reflected on the sample to obtain reflected light; receiving the reflected light by a hyperspectral imaging module to obtain a hyperspectral image of the reflected light spot, and extracting a gray image of the reflected light spot at each wavelength from the hyperspectral image; and obtaining the Goos-Haunchn shift of the sample at each wavelength according to the distribution of light intensity with pixel position in the gray image at each wavelength. On this basis, by comparing the Goos-Haunchn shift at each wavelength measured before and after the biochemical substance is attached to the surface of the sample, the wavelength corresponding to the maximum change in Goos-Haunchn shift is obtained, and then the Goos-Haunchn shift at the wavelength is used as a sensitivity parameter to detect the biochemical substance.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of optical precision measurement, in particular to a wavelength-resolved Goos-Ha nchen shift measurement method and a biochemical sensing method based thereon. BACKGROUND

[0002] Goos-Ha nchen shift is a phenomenon that a non-ideal plane wave deviates from the geometric optical path when reflected at the interface, and is an important research object in the current optical field. In addition to theoretical analysis, experimental measurement is also required for the study of Goos-Ha nchen shift. The existing Goos-Ha nchen shift measurement methods are all single-wavelength Goos-Ha nchen shift measurement using a laser light source. Goos-Ha nchen shift is generated during the reflection of light at the interface, and the interface reflection characteristics of light depend on the refractive index of the material on both sides of the reflection interface. Therefore, the wavelength-dependent characteristics of Goos-Ha nchen shift are caused by the dispersion characteristics of the refractive index of the material. Testing and analyzing the wavelength-dependent characteristics of Goos-Ha nchen shift are helpful to further understand the Goos-Ha nchen shift phenomenon, however, so far, there is no report on the dispersion characteristics of Goos-Ha nchen shift at home and abroad. At present, there are reports on displacement sensors and biochemical sensors based on Goos-Ha nchen shift measurement. By measuring the wavelength-resolved Goos-Ha nchen shift, not only the wavelength-dependent characteristics of Goos-Ha nchen shift can be understood and mastered, but also the performance optimization of such sensors can be achieved. Due to the lack of a means for quickly and accurately measuring wavelength-resolved Goos-Ha nchen shift in reality, this to some extent limits the further research and development of the corresponding sensors. SUMMARY

[0003] Therefore, in order to solve the above problems, a wavelength-resolved Goos-Ha nchen shift measurement method and a biochemical sensing method based thereon are proposed.

[0004] As a first aspect of the present application, a wavelength-resolved Goos-Ha nchen shift measurement method is provided, which is realized based on a hyperspectral imaging device including a light source module, a hyperspectral imaging module, a sample stage, and a signal processing module, and the measurement method comprises:

[0005] The incident light from the light source module is irradiated onto a sample placed on the sample stage, and the reflected light is obtained by reflecting the incident light on the sample, wherein the incident light is a visible-near infrared polarized parallel light beam; wherein the sample is configured to cause a phase difference between the reflected light on the sample surface relative to the incident light;

[0006] The hyperspectral imaging module is used to receive the reflected light to obtain a hyperspectral image of the reflected light spot. Grayscale images of the reflected light spot at various wavelengths are extracted from the hyperspectral image, where each wavelength is located in the visible-near-infrared band; wherein, each wavelength corresponds to a grayscale image.

[0007] The Gus-Hanshin displacement of the sample at each wavelength is obtained by analyzing the distribution of light intensity with pixel position in the grayscale image at each wavelength.

[0008] According to an embodiment of the present invention, the Gus-Hanshin displacement of the sample at various wavelengths is obtained based on the distribution of light intensity with pixel position in grayscale images at various wavelengths, including:

[0009] Based on the distribution of light intensity with pixel position in the grayscale image at each wavelength, the light intensity centroid of the reflected light spot corresponding to each wavelength is obtained;

[0010] The Gus-Hanshin displacement of the sample at various wavelengths is obtained based on the offset of the light intensity centroid relative to the target pixel in the grayscale image.

[0011] According to an embodiment of the present invention, the target pixel is the center pixel of the grayscale image of the reflected light spot.

[0012] According to an embodiment of the present invention, the Gus-Hanshin displacement is expressed as follows:

[0013]

[0014]

[0015] in, Indicates wavelength The displacement of Gus-Hanshin below, Indicates wavelength The coordinates of the centroid of the light intensity below. wavelength The coordinates of any pixel in the grayscale image. for The light intensity of a pixel, The direction is the direction of the component of the wave vector of the incident light on the surface of the sample. The axis is perpendicular to the wave vector component. direction, Direction and the normal direction of the sample surface ( (Direction) satisfies the right-hand screw rule. The size of the pixel.

[0016] According to an embodiment of the present invention, the sample stage includes: a displacement platform or a coupling prism.

[0017] According to the embodiment of the present application, when the sample stage is a coupling prism, the sample piece is a chip composed of a transparent substrate and one or more layers of thin films deposited on the transparent substrate, and the sample piece includes an SPR chip, a PWR chip, a resonant mirror chip, a metasurface chip, and a photonic crystal chip.

[0018] The sample piece is tightly attached to the bottom surface of the coupling prism by a coupling liquid, the incident light is irradiated onto the sample piece through the coupling prism, and total reflection occurs on the sample piece to generate the reflected light.

[0019] According to the embodiment of the present application, the visible-near infrared polarized parallel light beam is s-polarized light or p-polarized light or other linearly polarized light that can be decomposed into s-polarized component and p-polarized component.

[0020] According to the embodiment of the present application, the hyperspectral imaging device further includes a lens assembly,

[0021] The lens assembly is arranged between the sample piece and the hyperspectral imaging module, and the reflected light is received by the hyperspectral imaging module after passing through the lens assembly, thereby obtaining a hyperspectral image of the reflected light spot amplified by the lens assembly.

[0022] As a second aspect of the present application, a biochemical sensing method based on Gouy-Hinshin displacement measurement is also provided, including:

[0023] The sample piece is placed on the sample stage, and then the biochemical substance to be measured is placed on the surface of the sample piece, wherein the sample stage for placing the sample piece is selected as a coupling prism;

[0024] The Gouy-Hinshin displacement at each wavelength before and after the biochemical substance to be measured is placed on the surface of the sample piece is tested by using the detection method described above, thereby obtaining the Gouy-Hinshin displacement change amount caused by the biochemical substance to be measured at each wavelength;

[0025] By comparing the Gouy-Hinshin displacement change amounts measured at each wavelength, the optimal wavelength is determined, so that the Gouy-Hinshin displacement change amount corresponding to the optimal wavelength is the largest;

[0026] By testing the Gouy-Hinshin displacement change amount at the optimal wavelength, the information of the biochemical substance to be measured is obtained;

[0027] The information of the biochemical substance to be measured includes concentration, thickness, and refractive index.

[0028] According to the embodiment of the present application, the hyperspectral image obtained by the hyperspectral imaging module comprises a plurality of gray scale images at different wavelengths. Since each gray scale image corresponds to a wavelength, the Goos-Haunchn shift at each wavelength can be obtained according to the light intensity distribution of each gray scale image, and the determination method provided by the embodiment of the present application can obtain the Goos-Haunchn shift of the sample at multiple wavelengths at the same time, i.e., the wavelength-resolved Goos-Haunchn shift.

[0029] According to the embodiment of the present application, compared with the Goos-Haunchn shift measurement at a single wavelength, the simultaneous measurement of the Goos-Haunchn shift at multiple wavelengths helps us to comprehensively understand the Goos-Haunchn shift phenomenon occurring on the surface of the sample, and is beneficial to optimizing the performance of the sensor based on the Goos-Haunchn shift measurement. BRIEF DESCRIPTION OF DRAWINGS

[0030] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings of the embodiments will be briefly introduced below. Obviously, the drawings described in the following description are only related to some embodiments of the present application, but not limit the present application.

[0031] Figure 1 A schematic diagram of the hyperspectral imaging device provided by the embodiment of the present application is shown;

[0032] Figure 2 A determination method of the wavelength-resolved Goos-Haunchn shift provided by the embodiment of the present application is shown;

[0033] Figure 3 The center region of the hyperspectral image of the reflected light spot on the hyperspectral imaging module in Example 1 is shown;

[0034] Figure 4 The spectral curves of three pixel points of Figure 3 are shown;

[0035] Figure 5 The gray scale images of the reflected light spot at several specific wavelengths in Example 1 and the corresponding Goos-Haunchn shift of each gray scale image are shown;

[0036] Figure 6 The comparison between the simulation results and the experimental results of the SPR chip is given.

[0037] MARKED FOR EXPLANATION:

[0038] 1 - light source module;

[0039] 11 - light source;

[0040] 12 - polarizer;

[0041] 2 - hyperspectral imaging module;

[0042] 3 - sample stage;

[0043] 4-lens assembly;

[0044] 5-sample. DETAILED DESCRIPTION

[0045] In the process of realizing the present application, it is found that in the prior art, the measurement is mainly performed by comparing the difference of single-wavelength Goos-Ha nchen shift generated under different polarization modes (p-polarization mode and s-polarization mode). By using this method, combined with the wavelength scanning mode based on a tuning laser or a tuning filter, multi-wavelength Goos-Hanchen shift measurement can be performed in a relatively narrow spectral range, but it is impossible to realize wide-spectrum Goos-Hanchen shift measurement from the visible to the near-infrared band. At present, there is no report on wide-spectrum Goos-Hanchen shift measurement at home and abroad. The hyperspectral imager combines the functions of a spectrometer and an imager, has the characteristics of atlas and spectrum integration, wide spectral range, large number of spectral channels, and high spectral resolution, and provides an opportunity for realizing wide-spectrum Goos-Hanchen shift measurement. By wavelength scanning of the Goos-Hanchen shift through the hyperspectral imaging device, the shift under thousands of wavelengths can be obtained in one static imaging, and high-throughput Goos-Hanchen shift data can also be obtained by combining polarization mode scanning or angle scanning. The multi-wavelength Goos-Hanchen shift measurement method based on hyperspectral imaging is a great improvement on the basis of the traditional single-wavelength Goos-Hanchen shift measurement.

[0046] In order to make the objects, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to the embodiments and the accompanying drawings. However, the present application can be implemented in different forms, and should not be interpreted as being limited to the embodiments presented here. On the contrary, these embodiments are presented to make the application complete and fully, and to fully convey the scope of the present application to those skilled in the art. In the drawings, the sizes and relative sizes of the layers and regions can be exaggerated for clarity, and the same reference signs represent the same elements throughout.

[0047] The terms used herein are merely used to describe specific embodiments, and are not intended to limit the present application. The terms "include", "contain" and the like used herein indicate the existence of the described features, steps, operations and / or components, but do not exclude the existence or addition of one or more other features, steps, operations or components.

[0048] Figure 1 A schematic diagram of a hyperspectral imaging device provided by an embodiment of the present application is shown.

[0049] As shown in Figure 1 , the hyperspectral imaging device includes a light source module, a hyperspectral imaging module 2 and a sample stage 3.

[0050] Figure 2A wavelength-resolved Goos-Haunchn shift determination method is provided.

[0051] As shown in the figure, the determination method comprises operations S10-S30. Figure 2

[0052] Operation S10: incident light from a light source module is irradiated to a sample 5 placed on a sample stage 3, the incident light is reflected on the sample 5 to obtain reflected light, and the incident light is a visible-near infrared polarized parallel light beam; wherein the sample 5 is configured to enable the reflected light to produce a phase difference on the sample surface relative to the incident light.

[0053] Operation S20: the reflected light is received by a hyperspectral imaging module 2 to obtain a hyperspectral image of the reflected light spot, and a gray scale image of the reflected light spot at each wavelength is extracted from the hyperspectral image, each wavelength being located in the visible-near infrared band; wherein each wavelength corresponds to a gray scale image.

[0054] According to the embodiment of the present application, the hyperspectral imaging module 2 is suitable for imaging under each spectral channel in the visible-near infrared band, and each wavelength in operation S20 corresponds to each spectral channel of the hyperspectral imaging module.

[0055] Operation S30: according to the distribution of light intensity with pixel position in the gray scale image at each wavelength, the Goos-Haunchn shift of the sample at each wavelength is obtained.

[0056] According to the embodiment of the present application, the light source module comprises a light source 11 and a linear polarizer 12, the light emitted by the light source 11 is a spectral continuous high-intensity visible-near infrared parallel light, for example, parallel white light, and the light emitted by the light source 11 is converted into incident light by the linear polarizer 12.

[0057] According to the embodiment of the present application, the hyperspectral imaging device further comprises a lens assembly, and the reflected light is focused by the lens assembly 4 and then enters the hyperspectral imaging device 2.

[0058] The incident angle of the incident light on the sample is known, and the hyperspectral imaging module 2 may, for example, be a line scanning type hyperspectral imaging module based on grating spectrometry or a wavelength scanning type hyperspectral imaging module.

[0059] According to the embodiment of the present application, the hyperspectral image obtained by the hyperspectral imaging module 2 comprises a plurality of gray scale images. Since each gray scale image corresponds to a wavelength, the Goos-Haunchn shift at the wavelength can be obtained according to the light intensity distribution of each gray scale image, and the determination method provided by the embodiment of the present application can simultaneously obtain the Goos-Haunchn shift of the sample at multiple wavelengths, i.e., the wavelength-resolved Goos-Haunchn shift.

[0060] ​According to an embodiment of the present application, the wavelength-resolved Goos-Haunchn shift can more accurately reflect the characteristics of the sample relative to the Goos-Haunchn shift at a single wavelength.

[0061] According to an embodiment of the present application, in operation S30, the Goos-Haunchn shift of the sample at each wavelength is obtained according to the distribution of the light intensity of the gray-scale image at each wavelength with respect to the pixel position, including sub-operation S31 to sub-operation S32.

[0062] In sub-operation S31, the light intensity centroid of the reflected light spot corresponding to each wavelength is obtained according to the distribution of the light intensity of the gray-scale image at each wavelength with respect to the pixel position.

[0063] In sub-operation S32, the Goos-Haunchn shift of the sample at each wavelength is obtained according to the offset of the light intensity centroid with respect to the target pixel in the gray-scale image.

[0064] According to an embodiment of the present application, the target pixel is the center pixel of the gray-scale image of the reflected light spot, and the light intensity of the center pixel is the pixel value of the center pixel.

[0065] According to an embodiment of the present application, the Goos-Haunchn shift is expressed as follows:

[0066] (1)

[0067] (2)

[0068] wherein, represents the Goos-Haunchn shift at wavelength , represents the coordinates of the light intensity centroid at wavelength , is the coordinates of any pixel point in the gray-scale image at wavelength , is the light intensity of the pixel point, is the component of the wave vector of the incident light along the surface of the sample in the direction parallel to the wave vector, is the axis perpendicular to the wave vector component, the x direction, the y direction, and the normal direction (z direction) of the surface of the sample satisfy the right-hand screw rule, is the size of the pixel point.

[0069] ​According to the embodiment of the present application, there is at least one interface in the sample piece 5, and the interface in the sample piece 5 is a plane, when there are multiple interfaces in the sample piece 5, the multiple interfaces constitute a stacked structure and are parallel to each other. When there is only one interface in the sample piece 5, the sample piece can only include one medium, and the interface in the sample piece is the interface between the sample piece and the air. In addition, the sample piece 5 can also be composed of multiple layers of dielectric media with different refractive indexes, and interlayer reflection can occur between different layers.

[0070] According to the embodiment of the present application, the sample stage 3 includes a displacement platform or a coupling prism. When the displacement platform is used as the sample stage, the incident light can be directly incident on the sample piece and reflected to obtain reflected light.

[0071] According to the embodiment of the present application, the sample piece 5 can be a chip that produces a measurable Goos-Haunchn displacement under experimental conditions, including one of an SPR chip, a PWR chip, a resonant mirror chip, a metasurface chip, and a photonic crystal chip. Although the refractive index of all substances is theoretically related to the wavelength, the refractive index of most substances changes little in the visible-near infrared range, and the resulting multi-wavelength Goos-Haunchn displacement is also small. Therefore, a chip with a large wavelength-dependent optical resonance structure can be used as a sample piece, such as an SPR chip, a PWR chip, a resonant mirror chip, a metasurface chip, and a photonic crystal chip.

[0072] When the sample stage is a coupling prism, the sample piece is tightly attached to the bottom surface of the coupling prism through the coupling liquid, the incident light passes through the coupling prism and is incident on the sample piece, and total reflection occurs on the sample piece to produce reflected light. According to the embodiment of the present application, the visible-near infrared polarized parallel light beam is s-polarized light or p-polarized light or other linearly polarized light that can be decomposed into s-polarized component and p-polarized component.

[0073] According to the embodiment of the present application, the hyperspectral imaging device further includes a lens assembly 4, which is arranged between the sample piece 5 and the hyperspectral imaging module 2. The reflected light passes through the lens assembly 4 and is received by the hyperspectral imaging module 2 to obtain a hyperspectral image of the reflected light spot amplified by the lens assembly.

[0074] According to the embodiment of the present application, after the Goos-Haunchn displacement of the sample piece at multiple wavelengths is detected by the method in the embodiment of the present application, the results obtained by the embodiment of the present application can be verified by using the Fresnel multi-layer reflection formula. The specific verification process is as follows.

[0075] According to the embodiment of the present application, the Fresnel reflection coefficient of the incident light with a wavelength of at an incident angle of is obtained by the Fresnel multi-layer reflection formula, and the results obtained by the embodiment of the present application are verified according to the following formula: ​ The first order approximation of the lateral Goos-Haunchn displacement and the first order approximation of the angular Goos-Haunchn displacement are calculated.

[0076] (3)

[0077] (4)

[0078] wherein, denotes the wavelength the first order approximation of the lateral Goos-Haunchn displacement, denotes the wavelength the first order approximation of the angular Goos-Haunchn displacement. is the divergence of the reflected light spot, can be obtained by the radius of the reflected light spot and the distance of the propagation of the reflected light , which is specifically expressed as formula (5).

[0079] (5)

[0080] Finally, based on the distance of the propagation of the reflected light in the experiment, the theoretical value of the composite multi-wavelength Goos-Haunchn displacement can be obtained.

[0081] (6)

[0082] The Fresnel reflection coefficient in it is obtained by the Fresnel multi-layer reflection formula. The following takes the sample including five interface reflections as an example for illustration. The reflection coefficient of more layers can be obtained by nesting in this way. Among them, the sample table is a coupling prism, the sample is closely attached to the bottom surface of the coupling prism through the coupling liquid, the incident light transmits through the coupling prism to irradiate on the sample, and the total reflection occurs on the sample to produce reflected light.

[0083] When the light ray is incident at an incident angle i from medium 1 (which can be air, for example) to different interfaces of the sample (which can include stacked medium 2, medium 3, medium 4 and medium 5, for example), the reflection coefficient of the structure composed of the five-layer medium can be obtained by the following formula:

[0084] (7)

[0085] (8)

[0086] (9)

[0087] (10)

[0088] For s-polarized incident light, r ij is obtained by the following formula

[0089] (11)

[0090] For p-polarized incident light, r ij is obtained by the following formula

[0091] (12)

[0092] For other polarized light, it can be decomposed into p-polarized component and s-polarized component, and then the calculation is performed respectively and then synthesized.

[0093] Where, θ1 is the incident angle of light at the interface of the coupling prism and medium 1, θ i and θ j respectively represent the corresponding incident angle and refractive angle when the incident light is incident from medium i into medium j; λ is the wavelength of the incident light; n i is the refractive index of medium i; D i is the thickness of medium i; k i and k j respectively represent the vertical components of the propagation constant of the incident light in medium i and medium j; r 12345 is the total reflection coefficient of the five-layer structure, r 2345 represents the reflection coefficient of light in the four-layer structure composed of medium 2~medium 5; r 345 represents the reflection coefficient of light in the three-layer film structure composed of medium 3~medium 5; r ij represents the reflection coefficient of light on the interface of layer i and layer j.

[0094] As a second aspect of the present application, a biochemical sensing method based on the Goos-Haunche displacement determination is also provided, comprising operation S100~operation S400.

[0095] Operation S100, placing the sample piece 5 on the sample table, and then placing the biochemical substance to be measured on the surface of the sample piece 5; wherein the sample table 3 for placing the sample piece is selected as a coupling prism;

[0096] Operation S200, using the above detection method, testing the Goos-Haunche displacement at each wavelength before and after the biochemical substance to be measured is arranged on the surface of the sample piece 5, and obtaining the Goos-Haunche displacement change amount at each wavelength caused by the measured substance;

[0097] Operation S300, by comparing the Goos-Haunche displacement change amounts measured at each wavelength, determining the optimal wavelength, so that the Goos-Haunche displacement change amount corresponding to the optimal wavelength is the largest;;

[0098] Operation S400, by testing the Guass-Hanxin position change amount under the optimal wavelength, obtaining the information of the biochemical substance to be measured;

[0099] Wherein, the information of the biochemical substance includes concentration, thickness, refractive index, etc.

[0100] According to the embodiment of the present application, when detecting the biochemical substance, the biochemical substance to be measured is placed on the surface of the sample, the biochemical substance to be measured interacts with the light field on the surface of the sample, and further affects the Guass-Hanxin displacement of the sample, so that by detecting the movement amount of the Guass-Hanxin displacement caused by the biochemical substance to be measured before and after being placed on the surface of the sample, the information of the biochemical substance to be measured can be obtained.

[0101] According to the embodiment of the present application, the target wavelength with the best selection effect (the most obvious Guass-Hanxin displacement) can be selected at any wavelength to detect the biochemical substance, which can effectively improve the measurement accuracy.

[0102] In order to make the purpose, technical scheme and advantages of the present application more clear, the following will be combined with specific examples, and the attached drawings will be referred to. Figure 1 The present application is further described in detail. In these examples, an SPR chip with a 50nm gold film is selected as the sample, and the sample is placed on the prism, and the Kretschmann prism coupling structure is used.

[0103] Example 1

[0104] This embodiment measures the multi-wavelength Guass-Hanxin displacement generated by the SPR chip placed on the sample stage. This SPR chip is prepared by sputtering a 3nm thick chromium film and a 50nm thick gold film on a glass sheet.

[0105] In this example, the measurement steps of the Guass-Hanxin displacement of the sample placed on the sample stage at each wavelength are as follows:

[0106] Step A, the measured SPR chip is attached to the Kretschmann prism coupling structure, the glass side of the measured SPR chip is attached to the prism through the coupling liquid, the incident light is adjusted to p-polarization state through the polarizer to produce SPR phenomenon. Then adjust the lens assembly so that the reflected light spot can be clearly imaged on the hyperspectral imaging module. The distance of the reflected light propagation is measured .

[0107] Figure 3 The central region of the hyperspectral image of the reflected light spot on the hyperspectral imaging module in Example 1 is shown.

[0108] As Figure 3The center region of the hyperspectral image of the surface plasmon resonance (SPR) chip measured at an incident angle of 45° is shown. It can be found that there is a significant color difference along the y direction, while the color difference in the x direction is not obvious, which indicates that there is a wavelength-dependent Gouy-Hanchen shift in the y direction of the SPR chip. Among them, A, B, and C are three pixel points of the hyperspectral image formed by the reflected light spot on the hyperspectral imaging module. The spectral curves of A, B, and C are drawn along the y direction.

[0109] Figure 4 The spectral curves of the three pixel points are shown. Figure 3

[0110] As shown in Figure 4 , the spectral curves (intensity variation curves with wavelength) of A, B, and C are shown. Figure 4 It can be seen from the figure that the resonance wavelength of the SPR chip is 582.67 nm.

[0111] Figure 5 The gray scale images of several specific wavelengths in Example 1 and the Gouy-Hanchen shifts corresponding to each gray scale image are shown.

[0112] As shown in Figure 5 , the Gouy-Hanchen shifts obtained at three wavelengths in Example 1 are shown.

[0113] The resonance peak and two wavelengths on both sides are selected, and the three wavelengths obtained are: 547.83 nm, 582.67 nm, and 600.23 nm. Then the corresponding three gray scale images are extracted from the measured hyperspectral image. Among them, part (a) is the gray scale image corresponding to 547.83 nm, part (b) is the gray scale image corresponding to 547.83 nm, and part (c) is the gray scale image corresponding to 547.83 nm. In Figure 5 part (a), it can be seen that in the gray scale image at 547.83 nm, the intensity of each pixel increases along the y direction, so that the intensity centroid is in the upper part of the gray scale image; in Figure 5 part (b), it can be seen that in the gray scale image at 600.23 nm, the intensity of each pixel decreases along the y direction, so that the intensity centroid is in the lower part of the gray scale image; in Figure 5 part (c), it can be seen that in the gray scale image at 582.67 nm, the intensity of each pixel is relatively uniform, so that the intensity centroid is in the middle of the gray scale image. Figure 5 It is illustrated that there is an opposite Gouy-Hanchen shift on both sides of the resonance wavelength of the sample.

[0114] Figure 6 The comparison of the simulation results and experimental results of the SPR chip is given.

[0115] As​Figure 6 are shown, wherein Figure 6 (a) is the comparison of the experimental spectrum and the simulated spectrum of the B pixel point in Example 1; Figure 6 (b) is the simulation result of the relationship between the phase of the reflected light and the wavelength; Figure 6 (c) is the first-order approximation of the lateral Goos-Ha nchen shift and the first-order approximation of the angular Goos-Ha nchen shift obtained according to the Fresnel simulation formula; Figure 6 (d) is the simulation result and the experimental result of the Goos-Ha nchen shift.

[0116] From Figure 6 (a) can be seen that the experimental spectrum and the simulated spectrum of the B pixel point in Example 1 are relatively close. The size of each pixel point in the gray-scale image in Example 1 is . The spot radius of the reflected light is equal to 150 pixels, that is . The experimental determination result and the simulation result of the Goos-Ha nchen shift in Example 1 are shown in Figure 6 (d), and the experimental determination result and the simulation result of the Goos-Ha nchen shift in Example 1 are shown in Figure 6 (d) can be seen that the experimental determination result and the simulation result of the Goos-Ha nchen shift are highly consistent.

[0117] The wavelength-resolved Goos-Ha nchen shift determination method provided by the embodiment of the application replaces the single-wavelength light source module and the imaging device in the traditional Goos-Ha nchen shift measurement with a white light source module suitable for multiple wavelengths and a hyperspectral microscope, so that higher flux signals can be obtained, and the signal reference requirement is reduced. At the same time, the method has low equipment cost and simple operation, the theory involved in the simulation fitting is not complex, and it has very important practical significance for further studying the Goos-Ha nchen shift and the sensing and characterization based on the Goos-Ha nchen shift.

[0118] The above-described specific embodiments further illustrate the purpose, technical solutions and beneficial effects of the application. It should be understood that the above-described specific embodiments are only examples of the application and are not used to limit the application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the application should be included in the protection scope of the application.

Claims

1. A wavelength-resolved method for measuring the Gus-Hanshin shift, the method being implemented using a hyperspectral imaging device, the hyperspectral imaging device comprising a light source module, a hyperspectral imaging module, and a sample stage, the method comprising: Incident light from the light source module is directed onto a sample placed on the sample stage. The incident light is reflected off the sample to obtain reflected light. The incident light is a visible-near-infrared polarized parallel beam. The sample is configured such that the reflected light has a phase difference relative to the incident light on the sample surface. The hyperspectral imaging module is used to receive the reflected light to obtain a hyperspectral image of the reflected light spot. Grayscale images of the reflected light spot at various wavelengths are extracted from the hyperspectral image, where each wavelength is located in the visible-near-infrared band; wherein, each wavelength corresponds to a grayscale image. Based on the distribution of light intensity with pixel position in the grayscale image at each wavelength, the light intensity centroid of the reflected light spot corresponding to each wavelength is obtained; The Gus-Hanshin displacement of the sample at various wavelengths is obtained based on the offset of the light intensity centroid relative to the target pixel in the grayscale image.

2. The determination method according to claim 1, wherein, The target pixel is the center pixel of the grayscale image of the reflected light spot.

3. The determination method according to claim 2, wherein, The Gus-Hanshin displacement is expressed as follows: in, Indicates wavelength The displacement of Gus-Hanshin below, Indicates wavelength The coordinates of the centroid of the light intensity below. wavelength The coordinates of any pixel in the grayscale image. for The light intensity of a pixel, The direction is the direction of the component of the wave vector of the incident light on the surface of the sample. The axis is perpendicular to the wave vector component. direction, Direction and normal direction of the sample surface The direction satisfies the right-hand screw rule. The size of the pixel is given.

4. The determination method according to claim 1, wherein, The sample stage includes a displacement platform or a coupling prism.

5. The determination method according to claim 4, wherein, When the sample stage is a coupling prism, the sample is a chip consisting of a transparent substrate and one or more thin films deposited on the transparent substrate. The sample includes SPR chips, PWR chips, resonant mirror chips, metasurface chips, and photonic crystal chips. The sample is tightly attached to the bottom surface of the coupling prism by the coupling fluid. The incident light shines on the sample through the coupling prism and undergoes total internal reflection on the sample to generate the reflected light.

6. The determination method according to claim 1, wherein, The visible-near-infrared polarized parallel beam is s-polarized light, p-polarized light, or other linearly polarized light that can be decomposed into s-polarized and p-polarized components.

7. The determination method according to claim 1, wherein, The hyperspectral imaging device also includes a lens assembly. The lens assembly is disposed between the sample and the hyperspectral imaging module. The reflected light passes through the lens assembly and is received by the hyperspectral imaging module to obtain a hyperspectral image of the reflected light spot magnified by the lens assembly.

8. A biochemical sensing method based on Gus-Hanshin displacement measurement, comprising: The sample is placed on the sample stage, and then the biochemical substance to be tested is placed on the surface of the sample. The sample stage used to place the sample is a coupling prism. Using the measurement method of any one of claims 1 to 7, the Gus-Hanshin displacement at various wavelengths before and after the biochemical substance to be tested is placed on the surface of the sample is tested, and the change in Gus-Hanshin displacement at various wavelengths caused by the biochemical substance to be tested is obtained. By comparing the changes in Gus-Hanshin displacement measured at various wavelengths, the optimal wavelength is determined so that the change in Gus-Hanshin displacement corresponding to the optimal wavelength is maximized. Information about the biochemical substance to be tested was obtained by measuring the change in the Gus-Hanshin position at the optimal wavelength. The information of the biochemical substance to be tested includes its concentration, thickness, and refractive index.

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