CN-116087113-B - Polarization parameter imaging detection device and method based on surface plasmon resonance

CN116087113BCN 116087113 BCN116087113 BCN 116087113BCN-116087113-B

Abstract

The invention discloses a polarization parameter imaging detection device and a detection method based on surface plasmon resonance. The detection method comprises the steps that a light source system emits a light beam with stable power and controllable wavelength, the light beam enters a collimation system and then is output as a collimated light beam, the collimated light beam is converted into linearly polarized light through a polarizer in a polarization system, the linearly polarized light enters a prism coupling sensing system to be influenced by various samples in a micro-flow cell system, the surface plasma resonance effects with different degrees are excited and then are emitted, and the emitted light beam is received and imaged through a wave plate and an analyzer in the polarization system and a photoelectric detector in a photoelectric detection system. And inverting and calculating a series of polarization parameter images related to the amplitude and the phase of the emergent light beam by utilizing a polarization parameter imaging algorithm according to the light intensity image, thereby realizing detection of various samples in the micro-flow cell system. The invention has the advantages of high flux, high detection sensitivity, low detection limit and wide detection range.

Inventors

Xu Houxiang
XIONG JICHUAN
LIU XUEFENG
XU BIN
NI BIN
NI CHENYIN

Assignees

南京理工大学

Dates

Publication Date: 20260512
Application Date: 20230228

Claims (9)

1. The polarization parameter imaging detection device based on surface plasmon resonance is characterized by comprising a light source system, a collimation system, a polarization system, a prism coupling sensing system, a photoelectric detection system and a micro-flow cell system, wherein the light source system is used for emitting signal light, the collimation system is used for collimating the signal light, the polarization system is divided into a front polarization system and a rear polarization system by the prism coupling sensing system, the front polarization system is used for converting the collimated signal light into linear polarized light, the prism coupling sensing system is used for exciting a surface plasmon resonance effect to change the polarization property of the signal light and loading sample refractive index information into information light, the rear polarization system is used for extracting left-handed or right-handed polarization components of the signal light, the photoelectric detection system is used for collecting the signal light to form an image, the image is input into a computer, and the computer calculates the signal light according to the collected light intensity image by using a polarization parameter imaging inversion algorithm to obtain a series of polarization parameter images related to the refractive index properties of the corresponding samples in the micro-flow cell system, and the method is as follows: deducing by using a Fresnel formula and a Jones matrix, wherein the image acquired by the photoelectric detection system under each polarization state is as follows: + Wherein: , , Deducing: , , Inversion of I i according to the fourier series transform yields k 0 、k 1 and k 2 , denoted by I i : , , R s 、r p , phi and sin delta parameter maps are represented using I i : Wherein, I i is the corresponding light intensity image when the polarization angle theta i is adopted, N is the number of the light intensity images, k 0 、k 1 and k 2 are intermediate variables, r s is the amplitude of the s polarization component in the emergent beam, r p is the amplitude of the p polarization component in the emergent beam, phi is the ratio of the amplitude of the s polarization component to the amplitude of the p polarization component, sin delta is the phase difference of the s polarization component and the p polarization component in the emergent beam; the microfluidic cell system is independent of the optical axis, inputs a sample to be detected before detection, temporarily stores the sample in the detection process, and outputs the sample after detection.
2. The surface plasmon resonance-based polarization parameter imaging detection apparatus according to claim 1, wherein the signal beam emission source in the light source system is any one of an incandescent lamp, a halogen lamp, a fluorescent lamp, a metal halogen lamp, a sodium lamp, a xenon lamp, an LED lamp, a gas laser, a solid laser, a liquid laser, a semiconductor laser, an optical fiber laser, and an optical signal generating device, and the light source system further comprises one or more of an optical filter, a filter, an optical fiber, and a beam expander.
3. The polarization parameter imaging detection device based on surface plasmon resonance according to claim 1, wherein the signal light wavelength range is 200 nm-10.6 μm, and the signal light wavelength line width range is 0.1 nm-100 nm.
4. The surface plasmon resonance-based polarization parameter imaging detection apparatus of claim 1 wherein the collimation system comprises one or more of a biconvex lens, a plano-convex lens, a collimating lens group, and a laser collimating lens.
5. The surface plasmon resonance-based polarization parameter imaging detection device according to claim 1, wherein the front polarization system is composed of a polarizer, the polarizer is any one of a linear polarizer, a linear polarizer controlled by a micro rotating motor and a liquid crystal polarization modulator, the polarizer is used for outputting linearly polarized light with a controllable polarization angle, the polarization angle of the linearly polarized light is any one or more of 0-100 pi periods, the polarization angle of the linearly polarized light is periodically increased or decreased in a constant value within a range of 0-100 pi, and the polarization angle change period of the linearly polarized light is 0-100 pi.
6. The polarization parameter imaging detection device based on surface plasmon resonance according to claim 1, wherein the rear polarization system comprises a quarter wave plate and an analyzer, an included angle between a fast axis of the quarter wave plate and a transmission axis of the analyzer is 45 degrees, and the analyzer is a linear polarizer or a liquid crystal polarization modulator.
7. The polarization parameter imaging detection device based on surface plasmon resonance according to claim 1 is characterized in that the prism coupling sensing system comprises a direct coating scheme and a separated chip scheme, wherein the direct coating scheme is used for directly carrying out metal coating on one side surface of a prism, the separated scheme comprises a prism and a glass sheet, a metal coating layer is formed on the glass sheet, an uncoated surface of the glass sheet is coupled with the prism by using coupling liquid, the micro-flow cell is connected with the metal coating layer in the prism coupling sensing system to form an internal sample containing cavity, and the sample to be detected exists in the internal cavity of the micro-flow cell during detection.
8. The surface plasmon resonance-based polarization parameter imaging detection apparatus of claim 7 wherein the prism and the glass sheet are 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 comprises the steps of: Step1, starting and adjusting a light source system to output signal light; step2, filling samples into the microfluidic cell system by using a microfluidic pump or a peristaltic pump until the internal cavity of the microfluidic cell is filled; Step 3, using a computer to control a micro rotating motor to rotate a linear polaroid or a liquid crystal polarization modulator, or using a manual control linear polaroid to rotate, so that the polarization angle of a transmitted linear polarized light beam of a front polarization system is periodically changed within 0-2 pi, and simultaneously controlling a photoelectric detection system to collect a series of light intensity images formed by outgoing light beams of a rear polarization system on a detection surface under different polarization angles by the computer, and inputting the light intensity images into the computer; and 4, calculating the light intensity image acquired in the step 3 by a computer by using a polarization parameter imaging inversion algorithm to acquire a series of polarization parameter images related to the refraction index properties of the corresponding sample in the microfluidic cell system, wherein the specific method comprises the following steps: deducing by using a Fresnel formula and a Jones matrix, wherein the image acquired by the photoelectric detection system under each polarization state is as follows: + Wherein: , , Deducing: , , Inversion of I i according to the fourier series transform yields k 0 、k 1 and k 2 , denoted by I i : , , R s 、r p , phi and sin delta parameter maps are represented using I i : Wherein I i is the corresponding light intensity image when the polarization angle θ i is adopted, N is the number of light intensity images, k 0 、k 1 and k 2 are intermediate variables, r s is the amplitude of the s-polarized component in the outgoing beam, r p is the amplitude of the p-polarized component in the outgoing beam, phi is the ratio of the s-polarized component amplitude to the p-polarized component amplitude, sin delta is the phase difference between the s-polarized component and the p-polarized component in the outgoing beam.

Description

Polarization parameter imaging detection device and method based on surface plasmon resonance Technical Field The invention belongs to the field of optical detection, and particularly relates to a polarization parameter imaging detection device and method based on surface plasmon resonance. Background Surface Plasmon Resonance (SPR) is a physical optical phenomenon in which when incident light containing a p-polarized component is incident at an angle to an interface between two transparent media to induce total reflection (TIR), an evanescent wave is generated at this interface. If a nanoscale metal film with a negative real part of dielectric constant exists on the interface, incident light can simultaneously induce free electron oscillation on the Surface of the metal film, the oscillation is called Surface plasma (Surface Plasmons, SPs), the SPs can propagate for tens to hundreds of micrometers along the horizontal direction on the Surface of the metal film, the SPs can propagate in an exponential decay manner along the vertical direction, the sensing distance is usually less than 200 nanometers, and the free electron oscillation limited on the Surface of the metal film is called Surface plasma wave (Surface PlasmonWave, SPW). When the evanescent wave generated by total reflection and the SPW have the same wave vector and propagation direction, the evanescent wave and the SPW are coupled to generate SPR, most of energy of the evanescent wave is absorbed by the SPW, so that the light intensity of the reflected light is greatly attenuated, the angle of the incident light is adjusted, and when the light intensity of the reflected light is minimum, the angle is called a resonance angle (SPR angle), and the wavelength of the incident light is called a resonance wavelength. When the incident light conditions of the prism material, the metal film material and the structure are unchanged, the resonance angle or the resonance wavelength is extremely sensitive to the change of the refractive index of the photophobic medium, namely the resonance angle or the resonance wavelength is sensitive to the change of the refractive index of a sample to be detected, so that the SPR detection technology usually characterizes the change of the refractive index of the photophobic medium by the deviation of the resonance angle or the resonance wavelength, and the SPR refractive index sensor is a novel sensor which does not need fluorescent marks, is high in sensitivity and can detect in real time. With the increasing demand of various molecular detection in recent years, although the conventional SPR sensing technology has great advantages in terms of sensitivity, the number of samples analyzed at one time is small, and the detection progress is greatly slowed, so that a high-throughput SPR detection technology is needed to simultaneously complete detection of a plurality of sites of a sensing chip. The surface plasmon resonance imaging (Surface Plasmon Resonance imaging, SPRi) technology improved from the SPR sensing technology well solves the problems, and the SPRi technology is different from the SPR technology in that a camera is used for collecting reflected light, an SPR light intensity signal is converted into a picture, and the difference of the reflectivity of each detection channel of the sensing chip can be observed by a pixel value on the picture, so that the difference of the refractive indexes of the surface objects to be detected corresponding to each detection channel of the sensing chip is reflected, and the in-situ detection of each detection channel in the microfluidic pool on the surface of the sensing chip is realized. Although the SPRi sensing technology has a potential to be applied more than the conventional SPR technology, the single-point photodetector used in the conventional SPR technology has a higher sensitivity than the CCD camera used in the SPRi sensing technology due to a higher signal-to-noise ratio, a wide dynamic range and a fast response thereof, and the SPRi technology is limited in sensitivity to background noise by the CCD camera in practical use, and is often reduced in sensitivity by about an order of magnitude. Disclosure of Invention Aiming at the problems of poor detection performance and small detection flux of the SPR technology in the prior SPRi technology, the invention provides a polarization parameter imaging detection device and a detection method with high sensitivity, high detection flux and wide detection range based on the surface plasmon resonance effect while having the advantages of no fluorescent marking, real-time detection, simple operation and the like in the SPR detection technology and the SPRi detection technology. The technical scheme includes that the surface plasma resonance-based polarization parameter imaging detection device comprises a light source system, a collimation system, a polarization system, a prism coupling sensing system, a photoelectric detect