Polarization parameter imaging detection device and method based on surface plasmon resonance

Abstract

The application discloses a polarization parameter imaging detection device and method based on surface plasmon resonance. The detection method is as follows: a light source system emits a light beam with stable power and controllable wavelength; the light beam is output as a collimated light beam after entering a collimation system; the collimated light beam is converted into linearly polarized light by a polarizer in a polarization system; the linearly polarized light enters a prism coupling sensing system and is affected by various samples in a micro-flow pool system; the linearly polarized light is excited to different degrees of surface plasmon resonance effect and is emitted; the emitted light beam passes through a wave plate and an analyzer in the polarization system and is received by a photodetector in a photoelectric detection system to form an image. According to the light intensity image, a series of polarization parameter images related to the amplitude and phase of the emitted light beam are calculated by using a polarization parameter imaging algorithm, so that the detection of various samples in the micro-flow pool system is realized. The application has the advantages of high throughput, high detection sensitivity, low detection limit and wide detection range.

Description

Technical Field

[0001] This invention belongs to the field of optical detection, specifically a polarization parameter imaging detection device and method based on surface plasmon resonance. Background Technology

[0002] Surface plasmon resonance (SPR) is a physical optical phenomenon. When incident light containing a p-polarized component strikes the interface between two transparent media at a certain angle, inducing total internal reflection (TIR), an evanescent wave is generated at this interface. If a nanoscale metal thin film with a negative real part of dielectric constant exists at the interface, the incident light will simultaneously induce free electron oscillations on the surface of the metal thin film. These oscillations are called surface plasmons (SPs). SPs can propagate horizontally for tens to hundreds of micrometers along the surface of the metal thin film, and exhibit exponential decay in the vertical direction. The sensing distance is typically less than 200 nanometers. This free electron oscillation confined to the surface of the metal thin film is called a surface plasmon wave (SPW).

[0003] When the evanescent wave generated by total internal reflection has the same wave vector and propagation direction as the SPW (Special Perspective Wave), the evanescent wave couples with the SPW to generate SPR (Special Refractive Index). Most of the energy of the evanescent wave is absorbed by the SPW, resulting in a significant attenuation of the reflected light intensity. Adjusting the incident light angle, the angle at which the reflected light intensity is minimized is called the resonance angle (SPR angle), and the incident light wavelength is called the resonance wavelength. When the incident light conditions of the prism material, metal film material, and structure remain constant, the resonance angle or resonance wavelength is extremely sensitive to changes in the refractive index of the optically less dense medium. That is, the resonance angle or resonance wavelength is highly sensitive to changes in the refractive index of the sample under test. Therefore, SPR detection technology often uses the shift of the resonance angle or resonance wavelength to characterize changes in the refractive index of the optically less dense medium. The SPR refractive index sensor is a novel sensor that does not require fluorescent labeling, is highly sensitive, and can detect in real time.

[0004] With the increasing demand for various molecular detection methods in recent years, conventional SPR sensing technology, while offering significant advantages in sensitivity, suffers from limited sample size analysis, severely slowing down the detection process. Therefore, a high-throughput SPR detection technology capable of simultaneously detecting multiple sites on a sensor chip is urgently needed. Surface Plasmon Resonance Imaging (SPRi), an improvement on SPR sensing technology, effectively addresses this issue. The difference between SPRi and SPR lies in SPRi's use of a camera to collect reflected light, converting the SPR light intensity signal into an image. The pixel values ​​in the image reveal the reflectivity differences between various detection channels on the sensor chip, reflecting the refractive index differences of the analyte on the surface corresponding to each detection channel. This enables in-situ detection of each detection channel within the microfluidic cell on the sensor chip surface.

[0005] Although SPRi sensing technology has greater application potential than conventional SPR technology, from the perspective of system noise characteristics, the single-point photodetector used in conventional SPR technology has higher sensitivity than the CCD camera used in SPRi sensing technology due to its higher signal-to-noise ratio, wide dynamic range and fast response. In actual use, SPRi technology is often reduced in sensitivity by about an order of magnitude due to the sensitivity of CCD cameras to background noise. Summary of the Invention

[0006] To address the issues of poor detection performance of existing SPRi technology and low detection throughput of SPR technology, this invention, while possessing the advantages of SPR detection technology and SPRi detection technology such as no need for fluorescent labeling, real-time detection, and simple operation, provides a polarization parameter imaging detection device and method with high sensitivity, high detection throughput, and wide detection range based on surface plasmon resonance effect.

[0007] To achieve the above objectives, the technical solution adopted by this invention is as follows: a polarization parameter imaging detection device based on surface plasmon resonance, comprising a light source system, a collimation system, a polarization system, a prism-coupled sensing system, a photoelectric detection system, and a microfluidic cell system. The light source system is used to emit signal light; the collimation system is used to collimate the signal light; the polarization system is divided into a front polarization system and a back polarization system by the prism-coupled sensing system; the front polarization system is used to convert the collimated signal light into linearly polarized light; the prism-coupled sensing system is used to excite the surface plasmon resonance effect, thereby changing the polarization properties of the signal light and loading the sample refractive index information into the information light; the back polarization system is used to extract the left-hand or right-hand polarization component of the signal light; the photoelectric detection system is used to collect the signal light and form an image; the microfluidic cell system is independent of the optical axis, inputting the sample to be tested before detection, temporarily storing the sample during detection, and outputting the sample after detection.

[0008] Preferably, the signal beam source in the light source system is any one of incandescent lamp, halogen lamp, fluorescent lamp, metal halide lamp, sodium lamp, xenon lamp, LED lamp, gas laser, solid-state laser, liquid laser, semiconductor laser, fiber laser, and optical signal generating device; the light source system also includes one or more of filters, optical fibers, and beam expanders.

[0009] Preferably, the wavelength range of the signal light is 200nm to 10.6μm, and the linewidth range of the signal light wavelength is 0.1nm to 100nm.

[0010] Preferably, the collimation system includes one or more of the following: a biconvex lens, a plano-convex lens, a collimating lens, a collimating lens group, and a laser collimating lens.

[0011] Preferably, the pre-polarization system is composed of a polarizer, which is any one of a linear polarizer, a linear polarizer controlled by a micro-rotating motor, or a liquid crystal polarization modulator; the polarizer is used to output linearly polarized light with a controllable polarization angle; the polarization angle of the output linearly polarized light is any one or more of the period between 0 and 100π; the polarization angle of the linearly polarized light increases or decreases periodically with a fixed value within the range of 0 to 100π; the period of change of the polarization angle of the linearly polarized light is between 0 and 100π.

[0012] Preferably, the post-polarization system includes a quarter-wave plate and an analyzer; the angle between the fast axis of the quarter-wave plate and the transmission axis of the analyzer is 45 degrees; the analyzer is a linear polarizer or a liquid crystal polarization modulator.

[0013] Preferably, the prism coupling sensing system includes a direct coating scheme and a discrete chip scheme; the direct coating scheme involves directly coating one side surface of the prism with metal; the discrete scheme includes a prism and a glass plate, with a metal layer coated on the glass plate, and a coupling fluid is used to couple the uncoated surface of the glass plate to the prism; the microfluidic cell is connected to the metal coating in the prism coupling sensing system to form an internal sample chamber; the sample to be tested exists in the internal chamber of the microfluidic cell during detection.

[0014] Preferably, the prism and the glass sheet are made of the same material.

[0015] A polarization parameter imaging detection method based on surface plasmon resonance, and a polarization parameter imaging detection device based on surface plasmon resonance, comprising the following steps:

[0016] Step 1: Turn on and adjust the light source system to output signal light;

[0017] Step 2: Use a microfluidic pump or peristaltic pump to inject the sample into the microfluidic system until the internal chamber of the microfluidic cell is filled;

[0018] Step 3: Use a computer-controlled micro-rotating motor to rotate the linear polarizer or liquid crystal polarization modulator, or use manual control to rotate the linear polarizer, so that the polarization angle of the transmitted linear polarized beam of the front polarization system changes periodically within 0 to 2π. At the same time, the computer-controlled photoelectric detection system collects a series of light intensity images formed on the detection surface by the beam emitted from the rear polarization system at different polarization angles, and inputs them into the computer.

[0019] Step 4: The computer uses the polarization parameter imaging inversion algorithm to calculate the light intensity image acquired in Step 3, and obtains a series of polarization parameter images related to the refractive index properties of the corresponding sample in the microfluidic system.

[0020] Compared with existing technologies, the significant advantages of this invention are as follows: Compared with SPR detection technology, this invention has the advantage of high detection throughput; compared with SPRi detection technology, this invention can obtain images of different polarization states by changing the polarization state and polarization angle of the incident beam, and can calculate multi-parameter images such as amplitude, amplitude difference, amplitude ratio, and phase difference based on these images, thus more comprehensively reflecting the properties of the sample; this invention also has the advantages of high detection sensitivity and wide detection range. When this invention is used in biosensing fields such as molecular sensing, medical diagnostic testing, and environmental screening, compared with enzyme-linked immunosorbent assay (ELISA) and polymerase chain reaction (PCR), this invention has advantages such as low cost, no need for fluorescent labeling, real-time detection, and simple operation. Attached Figure Description

[0021] The accompanying drawings are provided to further illustrate embodiments of the present invention and form part of the specification. They are used together with the following detailed description to explain the embodiments of the present invention, but do not constitute a limitation thereof. In the drawings:

[0022] Figure 1 This is a schematic diagram of a polarization parameter imaging and detection device based on surface plasmon resonance.

[0023] Figure 2 This is a schematic diagram of a polarization parameter imaging detection device based on surface plasmon resonance in a specific embodiment.

[0024] Figure 3 In Example 2, the photoelectric detection system acquires a series of light intensity signal images at different polarization angles.

[0025] Figure 4 Images of various polarization parameters of the reaction sample's refractive index properties calculated by the polarization parameter imaging inversion algorithm. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of this invention clearer, the following description is provided in conjunction with the appendix. Figure 1 The present invention will be further described in detail below.

[0027] Combination Figure 1 This invention proposes a polarization parameter imaging and detection device based on surface plasmon resonance, comprising a light source system S1, a collimation system S2, a polarization system S3, a prism-coupled sensing system S4, a photoelectric detection system S5, and a microfluidic cell system S6. The polarization system S3 is divided into a front polarization system S3-f and a back polarization system S3-a. The microfluidic cell system S6 and the prism-coupled sensing system S4 together form a sample storage chamber. Furthermore, an additional computer PC controls the polarization system S3 and the photoelectric detection system S6 for polarization angle modulation and image acquisition, respectively.

[0028] Incident beam 1 is emitted by light source system S1. Incident beam 1 is converted into collimated beam 2 by collimation system S2. Collimated beam 2 enters the pre-polarization system S3-f and is converted into linearly polarized light 3. Linearly polarized light 3 is refracted on the prism surface and enters the prism-coupled sensing system. Refracted beam 4 strikes the metal coating layer inside the prism and undergoes total internal reflection. Reflected beam 5 is refracted out of the prism. Prism-out beam 6 passes through the post-polarization system. Signal beam 7 carrying sample property information finally reaches the photoelectric detection system and forms an image.

[0029] The aforementioned polarization parameter imaging detection device based on surface plasmon resonance uses a computer PC to control the pre-polarization system S3-f to change the polarization state and polarization angle of the collimated beam 2, and to control the photoelectric detection system S5 to simultaneously record the SPRi result images of the metal sensing coating surface sample under different polarization states using the prism-coupled sensing system S4. Then, based on the series of SPRi result images of samples at different polarization angles, various parameter images reflecting the sample properties are calculated, including the amplitude diagram r of the polarization component (TE wave) of the signal beam s. s Amplitude diagram of the p-polarization component (TM wave) r p The difference between the amplitudes of the s-polarization component and the p-polarization component is shown in the figure. s -r p or r p -r s Plot showing the ratio of the amplitude of the s-polarization component to the amplitude of the p-polarization component. Phase difference diagram of s-polarization component (TE wave) and p-polarization component (TM wave) sinδ.

[0030] This invention can monitor changes in properties such as the refractive index of samples in real time without requiring fluorescent labeling or other treatments. The detection principle is simple, and because the metal sensing coating in the prism-coupled sensing system S4 can be cleaned and reused, this invention offers a significant cost advantage. The detection device and method will be described below with reference to a specific embodiment.

[0031] Example 1

[0032] like Figure 2 As shown, in a specific embodiment 1, the detection device includes: a halogen lamp HL, a liquid crystal tunable filter LCTBF, plano-convex lenses L1, L2 and L3, a field stop D1, an aperture stop D2, a beam expander BE, a rectangular aperture stop D3, a polarizer P1 controlled by a rotary motor, a prism Prism, a quarter-wave plate QWP, an analyzer P2, a camera C, a computer PC, a microfluidic pool, and a pump.

[0033] Furthermore, the detection device is divided into several systems by black dashed lines, namely: light source system S1, collimation system S2, polarization system S3, prism coupling sensing system S4, photoelectric detection system S5, microfluidic cell system S6, and computer PC.

[0034] Furthermore, the light source system S1 includes a halogen lamp HL and a liquid crystal tunable filter LCTBF. The halogen lamp HL is turned on and off by a computer PC, and the liquid crystal tunable filter LCTBF is controlled by a computer to adjust the wavelength and linewidth of the output beam of the light source system S1.

[0035] Furthermore, the collimation system S2 includes plano-convex lenses L1, L2 and L3, field stop D1, aperture stop D2, beam expander BE, and rectangular aperture stop D3.

[0036] Specifically, in the collimation system, L1, D1, L2, D2 and L3, while playing a collimation role, also constitute the Kohler lighting system, effectively eliminating the image of the filament in the halogen lamp.

[0037] Specifically, the beam expander (BE) expands the light beam and further improves the collimation of the beam.

[0038] Specifically, the rectangular aperture stop D3 controls the shape and size of the output beam of the collimation system S2.

[0039] Furthermore, the pre-polarization system S3-f includes a polarizer P1 controlled by a rotating motor.

[0040] Specifically, the rotary motor is controlled by a computer PC and rotates at a fixed angle within a period of 0 to 2π.

[0041] Specifically, polarizer P1 is a linear polarizer.

[0042] Furthermore, the light source system S1, the collimation system S2, and the front polarization system S3-f need to remain coaxial.

[0043] Furthermore, the prism-coupled sensing system S4 includes a prism Prism.

[0044] Specifically, the Prism is an isosceles right-angle prism. The inclined surface of the Prism is first plated with 2nm thick chromium metal, and then 50nm thick gold is plated on the chromium layer.

[0045] Furthermore, the post-polarization system S3-a includes a quarter-wave plate QWP and an analyzer P2.

[0046] Specifically, the analyzer P2 is a linear polarizer, and the fast axis of the quarter-wave plate QWP is at a 45° angle to the transmission axis of the analyzer P2.

[0047] Furthermore, the photoelectric detection system S5 includes a camera C.

[0048] Specifically, camera C is a CCD camera, which is controlled by a computer PC to acquire images.

[0049] Furthermore, the microfluidic system S6 includes a microfluidic pool and a pump.

[0050] Specifically, the sample enters and exits the microfluidic pool via a pump, which is controlled by a computer PC.

[0051] Based on the surface plasmon resonance polarization parameter imaging detection device in the above specific embodiments, combined with Figure 2 The corresponding detection method is explained below, with detailed steps as follows:

[0052] Step 1. Turn on the halogen lamp HL and the liquid crystal tunable filter LCTBF in the light source system S1. Wait for the halogen lamp HL to work stably and for the liquid crystal tunable filter LCTBF to warm up. Then, use the computer PC to control the liquid crystal tunable filter LCTBF to adjust the output wavelength to 633nm.

[0053] Step 2. The computer PC controls the pump to input the test samples into the microfluidic pool until all samples have been input.

[0054] Step 3. The computer PC controls the rotating motor of the front polarization system S3-f to rotate within a period of 0 to 2π, with a single rotation angle of a fixed value of 10°. At the same time, the computer controls the CCD camera in the photoelectric detection system S5 to collect signal beams containing sample properties and image them at each rotation interval of the rotating motor until the end of the rotation cycle. In this embodiment, a total of 36 images are collected and stored in the computer PC.

[0055] Step 4. Run the polarization parameter imaging inversion algorithm on the computer to calculate the 36 images from Step 3, and obtain a series of polarization parameter images related to the sample properties, including the amplitude map r of the polarization component (TE wave) of the signal beam. s Amplitude diagram of the p-polarization component (TM wave) r pThe difference between the amplitudes of the s-polarization component and the p-polarization component is shown in the figure. s -r p or r p -r s Plot showing the ratio of the amplitude of the s-polarization component to the amplitude of the p-polarization component. Phase difference diagram of s-polarization component (TE wave) and p-polarization component (TM wave) sinδ.

[0056] Example 2

[0057] To make the technical solution and detection results of the present invention clearer, the detection device and detection method of Example 1 were used to detect NaCl solutions of different concentrations in Example 2.

[0058] Specifically, the NaCl solution includes six concentration gradients: 0%, 2.5%, 5%, 10%, 15%, and 20%, which correspond to refractive indices of approximately 1.3331, 1.3377, 1.3434, 1.3516, 1.3609, and 1.3701, respectively, at room temperature of 25°C.

[0059] Furthermore, combined Figure 3 The invention employs a polarization parameter imaging detection device and method based on surface plasmon resonance, yielding 36 initial signal images, as shown below. Figure 3 .

[0060] Furthermore, combined Figure 4 A polarization parameter imaging algorithm is run on a computer PC to obtain a series of polarization parameter images related to the sample properties, including the amplitude map of the s-polarization component (TE wave) of the signal beam. s Amplitude diagram of the p-polarization component (TM wave) r p The difference between the amplitudes of the s-polarization component and the p-polarization component is shown in the figure. s -r p or r p -r s Plot showing the ratio of the amplitude of the s-polarization component to the amplitude of the p-polarization component. The phase difference diagram sinδ between the s-polarization component (TE wave) and the p-polarization component (TM wave) is shown below. Figure 4 .

[0061] Furthermore, through analysis Figure 4 By analyzing the pixel values ​​of each detection channel in the polarization parameter image, the properties of the corresponding sample within each detection channel can be obtained, enabling qualitative and quantitative detection of the sample.

[0062] In summary, this invention proposes a polarization parameter imaging detection device and method based on surface plasmon resonance. Because the results are multiple polarization parameter images reflecting the sample properties, compared to conventional surface plasmon resonance detection methods, the results of this invention are more diverse, and the polarization parameter images can complement each other, providing a more comprehensive reflection of the sample properties from various angles. Therefore, the detection device and method proposed in this invention have advantages such as low cost, no need for fluorescent labeling, real-time detection, simple operation, high throughput, high detection sensitivity, low detection limit, and wide detection range.

[0063] The technical features of the above embodiments can be combined arbitrarily. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as the combinations of these technical features do not contradict each other, they should be considered within the scope of this specification.

[0064] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

[0065] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

Claims

1. A polarization parameter imaging and detection device based on surface plasmon resonance, characterized in that, The system includes a light source system, a collimation system, a polarization system, a prism-coupled sensing system, a photoelectric detection system, and a microfluidic cell system. The light source system emits signal light; the collimation system collimates the signal light; the polarization system is divided into a pre-polarization system and a post-polarization system by the prism-coupled sensing system; the pre-polarization system converts the collimated signal light into linearly polarized light; the prism-coupled sensing system excites surface plasmon resonance, changing the polarization properties of the signal light and loading the sample refractive index information into the information light; the post-polarization system extracts the left-hand or right-hand polarization component of the signal light; the photoelectric detection system collects the signal light, forms an image, and inputs it into a computer. The computer uses a polarization parameter imaging inversion algorithm to calculate a series of polarization parameter images related to the refractive index properties of the corresponding sample in the microfluidic cell system, specifically as follows: Using Fresnel's formula and Jones' matrix, the images acquired by the photoelectric detection system in each polarization state are derived as follows: + in: , , Derivation: ， ， Based on the Fourier series transform of I i Perform inversion calculations to obtain the result from I i k0, k1, and k2 are represented as follows: ， ， Use I i Indicates r s r p φ and sinδ parameter diagrams: Among them, I i Polarization angle θ i The corresponding light intensity image, N is the number of light intensity images, k0, k1 and k2 are intermediate variables, r s Let r be the amplitude of the s-polarization component in the outgoing beam. p φ is the amplitude of the p-polarized component in the outgoing beam, φ is the ratio of the amplitude of the s-polarized component to the amplitude of the p-polarized component, and sinδ is the phase difference between the s-polarized component and the p-polarized component in the outgoing beam. The microfluidic system is independent of the optical axis. The sample to be tested is input before detection, the sample is temporarily stored during detection, and the sample is output after detection.

2. The polarization parameter imaging and detection device based on surface plasmon resonance according to claim 1, characterized in that, The signal beam source in the light source system is any one of incandescent lamp, halogen lamp, fluorescent lamp, metal halide lamp, sodium lamp, xenon lamp, LED lamp, gas laser, solid-state laser, liquid laser, semiconductor laser, fiber laser, and optical signal generating device; the light source system also includes one or more of filters, optical fibers, and beam expanders.

3. The polarization parameter imaging and detection device based on surface plasmon resonance according to claim 1, characterized in that, The wavelength range of the signal light is 200nm~10.6μm, and the linewidth range of the signal light wavelength is 0.1nm~100nm.

4. The polarization parameter imaging and detection device based on surface plasmon resonance according to claim 1, characterized in that, The collimation system includes one or more of the following: a biconvex lens, a plano-convex lens, a collimating lens, a collimating lens group, and a laser collimating lens.

5. The polarization parameter imaging and detection device based on surface plasmon resonance according to claim 1, characterized in that, The pre-polarization system consists of a polarizer, which is any one of a linear polarizer, a linear polarizer controlled by a micro-rotating motor, or a liquid crystal polarization modulator; the polarizer is used to output linearly polarized light with a controllable polarization angle; the polarization angle of the output linearly polarized light is any one or more of the period between 0 and 100π; the polarization angle of the linearly polarized light increases or decreases periodically with a fixed value within the range of 0 to 100π; the period of change of the polarization angle of the linearly polarized light is between 0 and 100π.

6. The polarization parameter imaging and detection device based on surface plasmon resonance according to claim 1, characterized in that, The post-polarization system includes a quarter-wave plate and an analyzer; the angle between the fast axis of the quarter-wave plate and the transmission axis of the analyzer is 45 degrees; the analyzer is a linear polarizer or a liquid crystal polarization modulator.

7. The polarization parameter imaging and detection device based on surface plasmon resonance according to claim 1, characterized in that, The prism coupling sensing system includes a direct coating scheme and a discrete chip scheme. The direct coating scheme involves directly coating one side of the prism with metal. The discrete chip scheme includes a prism and a glass plate. A metal layer is coated on the glass plate, and a coupling fluid is used to couple the uncoated surface of the glass plate to the prism. The microfluidic cell is connected to the metal coating in the prism coupling sensing system to form an internal sample chamber. The sample to be tested exists in the internal chamber of the microfluidic cell during detection.

8. The polarization parameter imaging and detection device based on surface plasmon resonance according to claim 7, characterized in that, The prism and the glass sheet are made of the same material.

9. A polarization parameter imaging detection method based on surface plasmon resonance, characterized in that, The polarization parameter imaging detection device based on surface plasmon resonance according to any one of claims 1 to 8 includes the following steps: Step 1: Turn on and adjust the light source system to output signal light; Step 2: Use a microfluidic pump or peristaltic pump to inject the sample into the microfluidic system until the internal chamber of the microfluidic cell is filled; Step 3: Use a computer-controlled micro-rotating motor to rotate the linear polarizer or liquid crystal polarization modulator, or use manual control to rotate the linear polarizer, so that the polarization angle of the transmitted linear polarized beam of the front polarization system changes periodically within 0~2π. At the same time, the computer-controlled photoelectric detection system collects a series of light intensity images formed on the detection surface by the beam emitted from the rear polarization system at different polarization angles, and inputs them into the computer. Step 4: The computer calculates the polarization parameter images related to the refractive index properties of the corresponding samples in the microfluidic system using a polarization parameter imaging inversion algorithm based on the light intensity images acquired in Step 3. The specific method is as follows: Using Fresnel's formula and Jones' matrix, the images acquired by the photoelectric detection system in each polarization state are derived as follows: + in: , , Derivation: ， ， Based on the Fourier series transform of I i Perform inversion calculations to obtain the result from I i k0, k1, and k2 are represented as follows: ， ， Use I i Indicates r s r p φ and sinδ parameter diagrams: Among them, I i Polarization angle θ i The corresponding light intensity image, N is the number of light intensity images, k0, k1 and k2 are intermediate variables, r s Let r be the amplitude of the s-polarization component in the outgoing beam. p Let φ be the amplitude of the p-polarized component in the outgoing beam, φ be the ratio of the amplitude of the s-polarized component to the amplitude of the p-polarized component, and sinδ be the phase difference between the s-polarized component and the p-polarized component in the outgoing beam.

Images