CN106896095A - The micro-imaging technique of composite surface plasma resonance and surface-enhanced Raman - Google Patents

Abstract

The invention discloses a composite microscopic imaging technology of surface plasmon resonance (Surface Plasmon Resonance, SPR) and surface-enhanced Raman (Surface-enhanced Raman Scattering, SERS), and relates to the fields of surface plasmon primitives and surface-enhanced Raman . The technical gist of the invention: assemble the SPR-SERS comprehensive microscopic imaging system, use the nano-slit array grating dual-mode structure to excite and detect SPR and SERS. The SPR system determines the change of the excitation angle by measuring the movement of the SPR peak position to determine the change of the surface effective refractive index caused by the biomolecular reaction on the chip surface; the SERS system directly distinguishes the biomolecules themselves by measuring the Raman spectrum. The efficient and high-sensitivity detection of SPR and Raman relies on the dual-mode structure of the nano-slit array grating: the excitation light waves efficiently excite the SPR through the grating structure; the SPR generates dipole oscillations with the nano-gap during the propagation of the metal surface, and the surface generated by the SPR The electric field and the nano-slit dipole work together to enhance the surface localized electric field to obtain enhanced Raman signals.

Description

Composite Surface Plasmon Resonance and Surface Enhanced Raman Microscopic Imaging Technology

technical field

The invention relates to the field of surface plasmon elements and surface-enhanced Raman, a large-area periodic nano-slit array structure excites plasmon resonance and surface-enhanced Raman, and a microscopic imaging of composite surface plasmon resonance and surface-enhanced Raman technology.

Background technique

Surface Plasmon Resonance (SPR) is a quantum photoelectric phenomenon in which photons are incident on the surface of a noble metal, causing the electrons in the metal to oscillate with the electric field. SPR technology detects biomolecules by measuring the change of excitation coupling conditions caused by the change of surface effective refractive index after the interaction of biological substances on the metal interface, which is an indirect measurement; while Raman signal detection is a complete method. Measure directly. Raman scattering is the inelastic scattering of incident light by the sample to be measured. Its essence is that when the photon collides with the molecule inelastically, after the photon transfers energy to the molecule to be measured, the energy state of the molecule transitions and radiates, revealing the vibration of the molecule. Or spectroscopic techniques that rotate energy levels. Raman spectroscopy provides the inherent vibration and rotation modes of molecules in the material to be tested, which directly reflects the molecular structure of the sample to be tested. However, Raman scattering is a weak scattering process, and its detection is limited by background noise and fluorescence background. The Raman scattering cross section is about 10 ^-30cm2 , while the scattering cross section of the fluorescence process is about 10 ^-15cm2 . Compared with Raman scattering, the fluorescence signal is much higher than Raman scattering, which is why fluorescence technology is more commonly used. Raman signal electromagnetic field enhancement is a Raman enhancement effect induced by a local electric field (such as a rough metal surface can generate an enhanced local electric field); this so-called surface-enhanced Raman Scattering (Surface-enhanced Raman Scattering, The signal generated by SERS is proportional to the fourth power of the intensity of the optical field in which the molecule is exposed. Obviously, the enhancement of the Raman signal depends on the enhancement of the local electric field, and the local electric field is concentrated near the nano-resonance structure, so SERS is suitable for the direct resolution and detection of surface-attached molecules or protein molecules on the cell surface.

In view of the indirect detection of biomolecules by SPR technology and the direct resolution of molecules by Raman spectroscopy, in recent years, researchers have been exploring SPR Raman enhancement, or a dual-mode structure that combines the two modes. There have been studies on embedding silver nanoparticles into a grating structure to excite surface plasmons and enhance the local field between nanoparticles for surface-enhanced Raman detection. However, the silver particle layer used in this method is randomly formed, and it is impossible to precisely control the position of the nanoparticles and the formation method of the gap, so the repeatability of the detection results is low, so that it cannot be practically applied. In addition, some studies have produced periodic gold nano-bow-tie structures to form SPR and SERS substrates; the periodic structures excite surface plasmons, and the bow-tie structures excite dipole resonances to form strong local electric fields to enhance Raman signals. However, the production process of the nanostructured bow is cumbersome, and it needs to be produced by electron beam lithography or ion beam etching, and the expensive production cost cannot be practically promoted at all. Although the production cost can be reduced by using the nanoimprint method, the precision of the nanostructure transfer process cannot be guaranteed. Some studies use the 111 crystal orientation to perform wet etching on the silicon substrate to obtain a periodic triangular structure, and use the metal periodic structure to excite the surface plasmon localized electric field to enhance Raman. This method can achieve 80% Raman signal detection repetition rate, which basically meets the practical requirements. However, its enhancement method only enhances the Raman signal through surface plasmon resonance, and lacks the nanostructure to enhance the local field strength, resulting in a low enhancement rate and unable to perform high-precision biological detection.

The above methods can achieve surface plasmon-enhanced Raman detection or simultaneous detection of surface plasmon and surface Raman enhancement to a certain extent, but there are currently disadvantages such as high production cost, low precision, and poor practicability; in addition, SPR-SERS System coordination for microscopic imaging has not been reported yet.

Contents of the invention

The technical problem to be solved by the present invention is to provide a high-precision, practical composite surface plasmon resonance and surface-enhanced Raman microscopic imaging technology to realize surface plasmon resonance on the same chip. Efficient excitation and superenhancement of surface localized fields.

The technical scheme adopted in the present invention is as follows: an SPR-SERS comprehensive microscopic imaging system is assembled, and a nano-slit array grating dual-mode structure is used to simultaneously excite and detect SPR and SERS.

The SPR-SERS integrated microscopic imaging system is shown in Figure 1. A laser is introduced outside the white light illumination path of an ordinary microscope to excite surface plasmon resonance on the SPR-SERS composite functional chip for sensing biological samples on it; this laser can simultaneously stimulate local electric field enhancement and stimulate biological samples to produce Surface-enhanced Raman scattering; these two types of signals pass through the signal collection system of the microscope objective lens, and the optical path is separated to perform imaging display and data analysis respectively.

A large-area nano-slit array grating structure is used as the SPR-SERS composite chip, as shown in Figure 2, there are two nano-gaps on the order of 10 nanometers in one cycle to generate a strong local field. Excitation light waves efficiently excite SPR through the grating structure: For the microscopic illumination system, as shown in Figure 3, the parallel laser is focused by the microscopic objective lens and converged on the chip. The incident light reaching the chip includes the aperture angle and azimuth angle determined from zero degrees to the objective lens. It is all beams in the cone from zero to 360 degrees; the change of the incident direction of the laser in the aperture angle and azimuth angle provides the variable scanning required for SPR detection, that is, the dark light representing SPR excitation appears in the aperture angle and azimuth angle distribution. belt (see Figure 3(b)). The SPR generates dipole oscillations with the nano-gap during the propagation process on the metal surface, and the surface electric field generated by SPR interacts with the nano-slit dipole to enhance the surface localized electric field to obtain enhanced Raman signals.

Specific testing includes: illumination white light (not shown) is split by beam-splitting prism 3 and then focused and imaged by lens 4 on receiving screen 5 for general imaging inspection, including sample focusing, area selection, and sample contour observation. The human eye 1 can directly observe and form the image focused on the focal plane by the lens 2 . Introduce two wavelengths of laser light 15 outside the white light illumination path of ordinary microscopes (for example, apply the same optical path system from two ports, and introduce 633 nm and 785 nm lasers respectively), and pass through a set of lenses 14 and 12 to form parallel light. The phase diffuser 13 removes the spatial coherence of light to eliminate laser imaging spots (for SPR imaging), and the phase plate 11 and polarizer 10 are used to modulate the polarization state. The parallel laser beam is guided into the microscope objective lens 8 through the dichroic prism 7, and focused on the nano-slit array grating SPR-SERS chip area on the sample stage 9. The light focused on the area of the SPR-SERS chip is collected by the microscopic objective lens 8 to collect the reflected light beam and then guided to the next beam-splitting prism 6 through the beam-splitting prism 7 . The parallel light beams enter the SPR imaging system and the SERS detection system respectively through the filter 16: all the parallel light beams that excite the SPR pass through the filter 16, are focused by the lens 17, and are directed into the CCD camera (Charge Coupled Device, Charge Coupled Device) camera 18, and are received by the CCD camera The SPR signal (Fourier transform plane) computer displays the SPR image, and the movement of the excitation angle is represented by measuring the two dark bands representing the SPR excitation (as shown in Figure 3 (b)); the Raman scattered light is completely reflected by the filter 16 and passes through The mirror 19 changes the direction of the optical path, and after passing through the filter 20, the lens 21 focuses on the slit 22 on the Raman detection area (including gratings 23, 24 and CCD camera 25) 26, and the Raman detection area 26 receives the Raman Spectral signals, analyzing the intrinsic peaks of the molecules to directly resolve the molecules.

To sum up, the key of the present invention is to implement surface plasmon resonance excitation and surface-enhanced Raman excitation on the same chip, and use microscope imaging to realize simultaneous detection of surface plasmon and surface-enhanced Raman. The change of the excitation angle is determined by measuring the movement of the SPR peak position, so as to determine the change of the surface effective refractive index caused by the biomolecular reaction on the chip surface. At the same time, the strong local field caused by the coupling of the SPR on the metal surface and the nanoslit can be used to measure the Raman spectrum to directly resolve the biomolecules themselves. The indirect measurement of SPR and the direct determination of the Raman signal add certainty to the precise determination of the biological response on the sensing surface. In summary, the composite microscopic imaging technology proposed by the present invention has the advantages of low cost, high precision, and strong practicability, and can be widely used in biological detection and other fields.

Description of drawings

The invention will be illustrated by way of example with reference to the accompanying drawings, in which:

Figure 1 is a schematic diagram of SPR-SERS dual-mode chip composite microscopic imaging. 1 is the human eye, 2, 4, 12, 14, 17, and 21 are lenses, 3, 6, and 7 are dichroic prisms, 5 is a receiving screen, 8 is a microscope objective lens, 9 is a sample stage, 10 is a polarizer, and 11 is a 13 is a phase diffuser, 15 is a laser, 16 and 20 are filters, 18 and 25 are CCD cameras, 19 is a mirror, 22 is a slit, 23 and 24 are gratings, and 26 is a Raman detection area.

Figure 2(a) is a schematic diagram of the surface profile of the composite chip measured by the atomic force microscope. The nanoslit array structure and nanoslits are shown, and the height information of the oblique area in the figure is shown in Figure 2(b).

Fig. 2(b) is the slit scanning diagram of the composite chip. The slit scan map corresponds to the height information represented by the oblique area in the surface schematic diagram in Figure 2(a).

Figure 3(a) is a schematic diagram of the microscope. is the angle between the optical axis of the objective lens and the actual ray, It is the azimuth angle formed by the projection of a ray in the cone beam onto the circular plane and the x-axis direction, and the azimuth angle varies from 0 degrees to 360 degrees; The coordinates are depicted in Fig. 3(b).

Figure 3(b) shows that the incident angle is SPR image at time. The white circle line in the figure represents the Fourier transform plane of SPR, and the two black dark bands represent SPR excitation. The direction of the x-axis in the figure circles counterclockwise, corresponding to the azimuth Change from 0 degrees to 360 degrees; in the direction of the x-axis from the center of the circle radially outward, respectively corresponding to the aperture angle From 0 degrees to plus or minus the maximum aperture angle.

Figure 4 is a schematic diagram of the SPR excitation detection platform. 15 is a laser, 27 is a microscopic objective lens of 40 times and a numerical aperture of 0.65, 28 is a lens, 7 is a beam splitting prism, 8 is a microscopic objective lens of 40 times, a numerical aperture of 0.65 or 100 times, and a numerical aperture of 0.85, and 9 is Sample stage, 17 is a lens, 18 is a CCD camera, and 29 is a computer.

Figure 5 shows the SPR images under different dielectrics. The surrounding medium on the metal grating changes from air (air), pure water (H2O), 1%, 10%, 25%, 50%, 75% volume ratio ethylene glycol to pure ethylene glycol (Ey_Gl), corresponding to representative The dark band excited by SPR moves from the outside to the center.

Fig. 6 is the relationship curve of the SPR excitation angle changing with the recombination refraction under different dielectrics. The relationship between the excitation angle and the composite refractive index when the SPR surface dielectric is changed from pure water, 1% ethylene glycol to 100% ethylene glycol; 7 data points and a linear fitting curve are given.

Fig. 7 is the SPR excitation angle change curve under different concentrations of thiophenol solutions. When the concentration of thiophenol solution in the dielectric solution (in molar M) changes from 0M, 10 ^-2M , 10 ^-1M , 1M, 10M, the relationship between the SPR excitation angle and the concentration of thiophenol solution; 5 data points are given and a linear fitting curve.

Fig. 8 is the surface-enhanced Raman scattering spectra of thiophenol solutions with different concentrations. Four Raman spectra corresponding to thiophenol concentrations of 10 ^-6M , 10 ^-5M , 10 ^-4M , and 10 ^-3 M from bottom to top.

Fig. 9 shows the relationship between the average absolute intensity of the characteristic peak at 1023 cm ^-1 and the concentration of the thiophenol solution. The concentration of thiophenol solution in the dielectric solution varies from 10 ^-6M , 10 ^-5M , 10 ^-4M , and 10 ^-3 M, and the average absolute intensity of the peak at 1023cm ^-1 changes with the concentration of thiophenol; four data points and Linear fit curve.

The marks in the figure are: 1 human eye; 2 lens; 3 beam splitting prism; 4 lens; 5 receiving screen; 6 beam splitting prism; 7 beam splitting prism; ; 13 phase diffuser laser; 14 lens; 15 laser; 16 filter; 17 lens; 18 CCD camera; 19 mirror; 20 filter; 21 lens; 22 slit; 23 grating; 24 grating; 25 CCD camera; 26 Raman detection area; 27 40x/0.65 microscope objective lens; 28 lens; 29 computer; air means the coal quality is air; H2O means the coal quality is pure water; 1/1; 10% means that the coal quality is ethylene glycol and the volume ratio of pure water is 10%; 25% means that the coal quality is ethylene glycol and the volume ratio of pure water is 25%; 50% means coal 75% means that the coal quality is ethylene glycol and the volume ratio of pure water is 75%; 100% means that the coal quality is ethylene glycol to pure water. The water volume ratio is one hundred percent.

detailed description

All features disclosed in this specification, or steps in all methods or processes disclosed, may be combined in any manner, except for mutually exclusive features and/or steps.

Any feature disclosed in this specification, unless specifically stated, can be replaced by other alternative features that are equivalent or have similar purposes. That is, unless expressly stated otherwise, each feature is only one example of a series of equivalent or similar features.

The composite biochip shown in Figure 2 is used: the ordinary grating structure is parametrically coupled to form a new grating, and a nano-gap is formed between the old and new gratings, and there are two nano-gaps on the order of 10 nanometers in one period; the composite chip has a grating period of about 400 Or a slit array structure of 600 nanometers, corresponding to SPR excitation wavelengths of 633 or 785 nanometers, respectively. For the microscopic illumination system, the parallel light is focused by the microscopic objective lens and converged on the chip. The incident light reaching the chip includes all the beams in the cone with the azimuth angle from 0 degree to 360 degree determined by the aperture angle from zero degree to the objective lens. . The microscope focuses the incident plane wave into a cone-shaped distribution with incident angles ranging from , is the maximum aperture angle of the incident light wave (determined by the numerical aperture NA of the objective lens), , where n is the refractive index of the incident medium. As shown in Figure 3(a), the incident parallel light is transformed into an incident angle of , the incident surface (corresponding to the azimuth angle) is an infinite number of light waves with a range of 0-360︒. The change of the incident direction in the aperture angle and azimuth angle provides the variable scan required for SPR detection, that is, the dark band representing SPR excitation appears in the distribution of aperture angle and azimuth angle as shown in Figure 3(b). It can be seen from the schematic diagram of the microscope that the distribution of incident angles is symmetrical. If an SPR wave is excited at one incident angle, there must be an opposite incident angle to excite another SPR wave propagating in the opposite direction.

The SPR excitation detection platform of the composite dual-mode chip is shown in Figure 4. The 633nm or 785nm wavelength laser light 15 is filtered and collimated by the microscope objective lens 27 (40x/0.65) and the lens 28, and then becomes parallel light, which is directed into the microscope objective lens 8 (40x/0.65 or 100x/0.85) through the beam splitter prism 7 and focused on the sample (which is placed on sample stage 9). The light on the chip is reflected back through the objective lens 8, then changes direction after the dichroic prism 7, is focused by the lens 17, receives the SPR signal with the CCD camera 18 on its Fourier transform plane, and the computer 29 records the imaging information of the CCD camera 18. SPR bulk refractive index calibration and surface refractive index sensitivity test are carried out on this detection platform.

Carry out SPR body refractive index sensitivity calibration: ethylene glycol solutions with different concentration percentages are respectively configured according to the volume ratio of ethylene glycol and deionized water as 0%, 1%, 10%, 25%, 50%, 75%, and 100%. ; When carrying out each concentration point test, the solution is taken out with a pipette, dropped on the chip, a spacer is placed around it, and a cover glass is covered to ensure that the thickness of the liquid sample is 100 microns. Select 785nm laser as the excitation light source, collect reflected light through 40x/0.65 microscope objective lens, change the medium on the metal grating from air, pure water, 1% ethylene glycol to 100% ethylene glycol, and obtain different concentrations of Microscopic SPR image (Fourier surface, focal plane of imaging lens), as shown in Figure 5; through the relationship of volume ratio, according to n composite refractive index = water volume percentage n water + ethylene glycol volume percentage nEthylene glycol can calculate the refractive index of the mixed solution at a wavelength of 785 nm; linearly fitting the relationship between the excitation angle and the composite refractive index when the SPR surface dielectric changes from pure water, 1% ethylene glycol to 100% ethylene glycol As shown in Figure 6, it can be calculated that the excitation angle changes by 69.8° for every change in the refractive index unit (RIU), and the SPR body refractive index sensitivity of the composite chip S=69.8°/RIU.

The test and proof of the composite chip is carried out by selecting thiophenol, a Raman identification material commonly used in the literature. SPR biological detection is to measure the change of surface effective refractive index caused by metal surface reaction. Therefore, the physical quantity reflecting the detection performance of SPR is its surface refractive index sensitivity, that is, the surface molecular layer adsorption sensitivity. The sulfur atoms in the thiophenol combine with the metal to form a monolayer; the surface density of the monolayer bound on the metal is proportional to the concentration of the thiophenol solution. Use a pipette to take the thiophenol solution in analytical pure ethanol to obtain thiophenol with a solubility of 10 ^-6M , 10 ^-5M , 10 ^-4M , 10 ^-3 M , 10 ^-2M , 10 ^-1M , and 1M. solution, put it in an ultrasonic cleaning machine and use 60% power to sonicate at room temperature for 2 minutes, so that the thiophenol molecules are evenly distributed in the solution.

Before testing each SPR concentration point, put the chips into the above-mentioned 10 ^-2M , 10 ^-1M , 1M, 10M thiophenol solutions sequentially, and soak for 2 hours to allow thiophenol molecules to be adsorbed on the surface. After soaking, take out the sample piece from the thiophenol solution, put it into the ethanol solution, rinse it for 2-3 seconds, and then take it out. The rinsed samples were placed in a nitrogen drying cabinet, dried in a nitrogen flow, and then tested for later use. Take the composite test sample on the sample stage 9, and use a 100x/0.85 microscope objective lens to focus and excite SPR. According to the above test process, the SPR signal of the composite chip was measured when no thiophenol solution was deposited, and it was used as a reference point with a concentration of 0 M.

Before each Raman concentration point test, soak the chip in 10 ^-6M , 10 ^-5M , 10 ^-4M , 10 ^-3 M thiophenol solution for 4 hours, take it out, rinse in ethanol solution for 2-3 Take it out in seconds. The rinsed samples were placed in a nitrogen drying cabinet, dried in a nitrogen flow, and then tested for later use. Use tweezers to place the test sample on the sample stage of the Raman detection platform of the Raman-atomic force coupling system. The laser with a wavelength of 633 nm or 785 nm is used as the excitation light source, and the laser power reaching the sample is 0.1 mW or 2.5 mW. Focusing with 50x/0.5 objective lens, excitation spot size is 2 , scan 3 times and integrate for 3 seconds.

Take the test sample on the sample stage 9 shown in FIG. 4 , use a 100x/0.85 microscope objective lens to focus and excite SPR, and select a 633 nm laser as the excitation light source. According to the aforementioned sample preparation method, test the sample to be tested with the ^SPR composite chip with ^0M thiophenol concentration;

When the concentration of thiophenol solution in the dielectric solution changes from 0M, 10 ^-2M , 10 ^-1M , 1M, 10M, the relationship between the SPR excitation angle and the concentration of thiophenol solution is shown in Figure 7, and each data point represents the test The average value of 4 different positions on the sample area, the standard deviation value in the measurement is given by error bars; the slope line is the linear curve fitted with the average value of the SPR excitation angle at each concentration. When the concentration of thiophenol is low, such as 10 ^-2M and 10 ^-1M ; when the concentration of thiophenol is 10M, the SPR excitation angle deviates greatly. According to the linear fitting equation , the surface sensing sensitivity S _surface of the composite chip is 1.5°/M when the excitation angle is changed by 1.5° for every unit concentration change.

With the application of composite chips, SPR and Raman scattering detection can be obtained at the same time. It is only necessary to pass the reflection signal into the Raman spectrometer, and the SPR signal into the SPR imager. The Raman detection platform of the Raman-atomic force combined system is the same as the principle of the Raman detection part in Figure 1. Considering that the composite chip is very sensitive to high-concentration thiophenol molecules, and the excitation intensity reaches saturation, a low-concentration thiophenol solution was used for Raman detection. Use a 50x/0.5 objective lens to focus, the focus spot size is 2 microns, scan 3 times, and integrate for 3 seconds. As shown in Figure 8, thiophenol solutions with concentrations of 10 ^-6M , 10 ^-5M , 10 ^-4M and 10 ^-3 M The Raman spectrum below. Corresponding to the four Raman spectra of 10 ^-6M , 10 ^-5M , 10 ^-4M , and 10 ^-3 M from bottom to top, the characteristic peaks of thiophenol are obvious; as the concentration of thiophenol decreases, the Raman light intensity reduce. When the concentration is reduced to 10 ^-15M , a strong Raman signal can still be detected. The characteristic peaks and high signal-to-noise ratio in the Raman spectrum show a high Raman enhancement effect, and the enhancement factor of SERS is 10 ⁶ .

Take the relationship between the absolute intensity average value of the characteristic peak position and the concentration of the thiophenol solution to make Figure 9. Each data point represents the absolute intensity average value of the 1023cm ^-1 peak position of the Raman spectrum in the test sample area, wherein each concentration point is scanned three times and averaged; the oblique line is the absolute intensity value of the 1023cm ^-1 peak position under each concentration linear fit curve, ; standard deviation is indicated by the error bars in the figure. When the concentration of thiophenol is high, such as 10 ^-4 M , 10 ^-3 M; the absolute intensity deviates greatly due to concentration saturation.

Combining the SPR microscopic imaging device shown in Figure 4 and the commercial Raman microscopic system, the nano-slit array grating structure is used to realize surface plasmon SPR detection and surface-enhanced Raman scattering SERS detection on the same chip. Applying the microscopic system shown in Fig. 1 of the present invention, combined with a large-area nano-slit array grating structure as an SPR-SERS composite chip, the efficient and high-sensitivity detection of SPR and Raman can be realized simultaneously on the same SPR-SERS chip.

The present invention is not limited to the foregoing specific embodiments. The present invention extends to any new feature or any new combination disclosed in this specification, and any new method or process step or any new combination disclosed.

Claims (5)

1. A composite surface plasmon (Surface Plasmon Resonance, SPR) label-free detection and surface-enhanced Raman Scattering (Surface-enhanced Raman Scattering, SERS) microscopic imaging technology; It is characterized in that, on the basis of ordinary microscope contour imaging, the efficient excitation of surface plasmon resonance and the enhancement of surface local field are realized on the same chip; the simultaneous efficient excitation of SPR and SERS is through a large-area periodic nano-slit implemented by the array structure. 2. The microscopic imaging technology according to claim 1, characterized in that the microscopic illumination system focuses the parallel light through the microscopic objective lens and converges on the chip, and the incident light reaching the chip includes an aperture angle determined by the zero degree to the objective lens , and all beams within the cone from zero degrees to 360° in azimuth. 3. The efficient excitation of realizing surface plasmon resonance according to claim 1 is characterized in that the large-area periodic nano-slit array structure can excite SPR, and the mutual coupling of SPR and nano-gap enhances the surface local field, and the enhanced strong local field The SPR is further enhanced to obtain efficient excitation of the SPR; the microscopic SPR image is received on the lens Fourier transform plane through a CCD (Charge Coupled Device, Charge Coupled Device) camera. 4. The method for realizing surface-enhanced Raman scattering according to claim 1 is characterized in that the large-area periodic nano-slit array structure can excite efficient SPR, and SPR generates dipole oscillation with nano-gap during metal surface propagation; SPR The generated surface electric field enhancement and the nano-slit local dipole field work together to enhance the surface local field to obtain a strong Raman signal. 5. According to claim 1, the high-efficiency excitation of surface plasmon resonance and the enhancement of surface local field are realized simultaneously, and it is characterized in that two kinds of wavelengths are used, and the same chip is used to simultaneously measure the SPR signal and the characterization of the angular spectrum information. Raman signal for intensity information.