Spectral detection apparatus and method based on surface-enhanced raman spectroscopy and weak value amplification

Abstract

The application discloses a spectral detection device and method based on surface-enhanced Raman spectrum and weak value amplification, which comprises a laser, a reflecting lens module, a trapezoidal prism, a refracting lens module, a spectrometer and a computer; a sample to be detected is attached to the rear surface of the trapezoidal prism; the light beam emitted by the laser is incident from two side surfaces of the trapezoidal prism through the reflecting lens module; the incident light is reflected in the trapezoidal prism for multiple times, so that multiple focal points are focused on the rear surface of the trapezoidal prism and then on the sample to be detected, and the sample to be detected is excited to generate Raman scattered light; after the Raman scattered light passes through the front surface of the trapezoidal prism, the Raman scattered light enters the spectrometer through the refracting lens module; the spectrometer transmits the spectral information original data of the Raman scattered light to the computer for processing and analysis, and the concentration information and the substance type of the sample to be detected are obtained. The application realizes the effective combination of the weak value amplification effect and the surface-enhanced Raman spectrum, improves the detection sensitivity, and realizes the detection which breaks through the standard quantum limit.

Description

Technical Field

[0001] This invention belongs to the field of laser spectroscopy measurement technology, specifically relating to a spectral detection device and method based on surface-enhanced Raman spectroscopy and weak-value amplification. Background Technology

[0002] Currently, spectroscopic detection technology is widely used in many fields. However, traditional spectroscopic detection methods still have limitations in terms of detection sensitivity and accuracy, especially for the detection of trace substances. Surface-enhanced Raman spectroscopy (SERS) is a technique that amplifies the Raman scattering signal by contacting the sample with a metal nanostructure that resonates with surface plasmon resonance. This amplification effect can significantly improve signal intensity, making the analysis of trace substances possible. In the field of chemical analysis, SERS is widely used in drug analysis, environmental monitoring, and food safety. Weak amplification utilizes certain physical or chemical processes to amplify weak signals, thereby improving detection sensitivity and accuracy. In spectroscopic detection, combining weak amplification with SERS technology can improve detection signal intensity and performance; therefore, how to combine weak amplification with SERS technology has become a pressing problem to be solved in spectroscopic detection. Summary of the Invention

[0003] In view of this, the present invention provides a spectral detection device and method based on surface-enhanced Raman spectroscopy and weak value amplification, which can design an optical path to achieve an effective combination of weak value amplification effect and surface-enhanced Raman spectroscopy, so as to solve the problem of high sensitivity detection of weak spectral signals in Raman spectroscopy detection and achieve detection that breaks through the standard quantum limit.

[0004] This invention is achieved through the following technical solution:

[0005] A spectroscopic detection device based on surface-enhanced Raman spectroscopy and weak amplification effect, comprising: a laser, a reflective lens module, a trapezoidal prism, a refractive lens module, a spectrometer, and a computer;

[0006] The sample to be tested has a reinforcing substrate material; the sample to be tested is attached to the back surface of the trapezoidal prism;

[0007] The laser emits a laser beam, which is collimated, filtered, polarized, split, and reflected by a reflective lens module to form incident light that enters from two sides of a trapezoidal prism. The incident light undergoes multiple reflections within the trapezoidal prism, causing multiple focal points to be simultaneously focused onto the rear surface of the trapezoidal prism, and then onto the sample under test. The reinforcing substrate material on the sample under test is excited by the incident light to generate surface-enhanced Raman spectra, i.e., Raman scattering light.

[0008] The generated Raman scattered light passes through the front surface of the trapezoidal prism and enters the refractive lens module. After being focused, collimated, refocused, filtered, polarization-state converted, polarized, and coupled by the refractive lens module, the Raman scattered light forms the outgoing light and enters the spectrometer. The spectrometer transmits the raw spectral information of the outgoing light to the computer. The computer processes and analyzes the sample to obtain the concentration information of the sample and determines the type of substance in the sample, thus completing the detection of the sample.

[0009] Furthermore, the trapezoidal prism is a prism with a trapezoidal cross-section, and the two sides of the trapezoidal prism are coated with an anti-reflection coating for incident light and an anti-reflection coating for Raman scattered light; the front surface of the trapezoidal prism is coated with an anti-reflection coating for incident light and an anti-reflection coating for Raman scattered light; the rear surface of the trapezoidal prism is coated with an anti-reflection coating for incident light and an anti-reflection coating for Raman scattered light.

[0010] Furthermore, the reflective lens module includes: a collimating lens, a Gaussian filter, a polarizer, a beam splitter, a spherical lens, a parabolic mirror, a reflecting mirror, and a second parabolic mirror;

[0011] The collimating lens, Gaussian filter, polarizer one, beam splitter, and spherical lens one are sequentially distributed between the laser and the trapezoidal prism. The optical axes of the collimating lens, Gaussian filter, polarizer one, and beam splitter are aligned. The reflecting mirror and spherical lens one are located on two mutually perpendicular exit directions of the beam splitter. The spherical surface of spherical lens one faces the beam splitter. The optical axis of spherical lens one is located between the optical axis of the beam splitter and the optical axis of the reflecting mirror, and it is aligned with the optical axis of the trapezoidal prism. Parabolic mirror one and parabolic mirror two are located on either side of spherical lens one and are symmetrically arranged along its optical axis. The parabolic surfaces of parabolic mirror one and parabolic mirror two face the spherical surface of spherical lens one.

[0012] The laser beam generated by the laser is collimated by a collimating lens, filtered by a Gaussian filter, and then polarized by a polarizer. The polarized beam is then split into two beams by a beam splitter. One beam goes directly to a spherical lens, while the other beam is reflected by a mirror and then goes to a spherical lens. The two beams that reach the spherical lens are symmetrically arranged along the optical axis of the spherical lens. After being reflected again by the spherical surface of the spherical lens, they go to parabolic mirrors one and two, respectively. The light reflected by the parabolic surfaces of parabolic mirrors one and two forms incident light that enters from the two sides of the trapezoidal prism.

[0013] Furthermore, the refractive lens module includes: a focusing lens one, a cemented lens, a focusing lens two, a spherical lens two, a collimator one, a collimator two, a filter, a quarter-wave plate one, a quarter-wave plate two, a polarizer two, and a coupling lens;

[0014] The focusing lens 1, cemented lens, focusing lens 2, spherical lens 2, and collimator 1 are sequentially distributed between the trapezoidal prism and the spherical lens 1, and the optical axes of the focusing lens 1, cemented lens, focusing lens 2, spherical lens 2, and collimator 1 are aligned with the optical axis of the trapezoidal prism; the collimator 1 and collimator 2 are connected by an optical fiber.

[0015] The collimator II, filter, quarter-wave plate I, quarter-wave plate II, polarizer II, and coupling lens have the same optical axis and are distributed in sequence; among them, the coupling lens is located closest to the spectrometer.

[0016] Raman scattered light transmitted from the front surface of the trapezoidal prism is focused by focusing lens one, collimated by a cemented lens, and then focused again by focusing lens two. The focused Raman scattered light is then transmitted through spherical lens two and focused onto collimator one. Collimator one transmits the light beam to collimator two through an optical fiber. The light beam exiting collimator two is filtered by a filter, then passes through quarter-wave plate one, quarter-wave plate two, and polarizer two in sequence for polarization state conversion. Finally, it is coupled by a coupling lens to form the outgoing light, which then enters the spectrometer. Quarter-wave plate one and quarter-wave plate two are used to adjust the angle of the polarized light after polarization by polarizer two.

[0017] Furthermore, the spectral detection device also includes a displacement control drive. The computer controls the forward and backward movement of the spherical lens one through the displacement control drive, changes the position of the light beam incident on the parabolic mirror one and the parabolic mirror two, and thus controls the number of focal points focused on the sample to be tested and the amount of focused energy.

[0018] A detection method for a surface-enhanced Raman spectroscopy and weak-value amplification spectroscopic detection device, the specific steps of which are as follows:

[0019] Step 1: Coat different surfaces of the trapezoidal prism of the spectral detection device with corresponding dielectric films; the coatings on the two sides of the trapezoidal prism are anti-reflection coatings for incident light and anti-reflection coatings for Raman scattered light; the coatings on the front surface of the trapezoidal prism are anti-reflection coatings for incident light and anti-reflection coatings for Raman scattered light; the coatings on the back surface of the trapezoidal prism are anti-reflection coatings for incident light and anti-reflection coatings for Raman scattered light.

[0020] Step 2: Fit and fix the sample to be tested onto the back surface of the trapezoidal prism;

[0021] Step 3: Using a prism-based reflective lens module in conjunction with a trapezoidal prism, the multiple reflection characteristics of the trapezoidal prism allow multiple focal points to be simultaneously focused onto the rear surface of the trapezoidal prism. The light energy is fully concentrated on the rear surface of the trapezoidal prism to excite the sample to generate surface-enhanced Raman spectra, i.e., Raman scattered light. At the same time, the scattered Raman light is collected using a prism-based refractive lens module.

[0022] Specifically, when a surface-enhanced Raman spectrum is generated on the sample to be tested, a spectral change is introduced into the optical path of the spectral detection device, and this spectral change is amplified by the spectral detection device; the amplification is achieved by introducing a post-selective state to achieve a weak value amplification effect; the magnitude of the weak value is determined by the pre- and post-selective states, and the pre- and post-selective states of the spectral detection device are jointly achieved by a waveplate and a polarizer;

[0023] Step four: The spectrometer transmits the raw spectral information of the collected scattered Raman light to the computer. The computer then performs quantitative and qualitative processing, analysis, and real-time display of the data to obtain the concentration information of the sample and determine the type of substance in the sample, thus completing the detection of the sample.

[0024] Furthermore, in step three, the pre- and post-selection states of the spectral detection device are achieved by a polarizer, as follows:

[0025] The reflective lens module includes polarizer one, and the refractive lens module includes quarter-wave plate one, quarter-wave plate two, and polarizer two. The pre-selection process of the pre-selection state of the spectral detection device is determined by polarizer one, and the post-selection process of the post-selection state of the spectral detection device is determined by polarizer two. Quarter-wave plate one and quarter-wave plate two are used to adjust the phase difference between the horizontal and vertical polarization components. By adjusting the rotation angle of quarter-wave plate one and quarter-wave plate two, when the post-selection state and the pre-selection state are orthogonal, that is, when the polarized light emitted from polarizer one is orthogonal to the polarized light emitted from polarizer two, the observed value can be amplified to be greater than the eigenvalue.

[0026] When measuring Raman spectral intensity, the Raman spectral intensity of the sample is related to its refractive index n. According to perturbation theory, the scattering cross section of Raman scattering can be expressed by the following formula:

[0027]

[0028] In the formula, σ is the scattering cross section, n is the refractive index of the sample to be tested, λ is the wavelength of the incident light, NA is Avogadro's constant, α is the polarizability of the sample to be tested, and Γ(ω) is the spectral shape function of the Raman scattered light.

[0029] The Raman spectral intensity can be calculated by calculating the scattering cross section. The relationship between Raman spectral intensity and scattering cross section is given by the following formula:

[0030]

[0031] In the formula, I is the scattering intensity, I0 is the intensity of the laser, λ is the wavelength of the incident light, r is the distance between the front surface of the sample and the optical center of the focusing lens, and c is the speed of light. The front surface of the sample is the surface of the sample that is in contact with the trapezoidal prism.

[0032] Furthermore, in step four, the computer transmits a control signal to the displacement control drive. The displacement control drive controls the spherical lens in the reflective lens module to move back and forth according to the control signal, thereby adjusting the number of focal points focused on the rear surface of the trapezoidal prism, so as to change the incident light intensity and incident light power density, and realize the detection of different types of samples to be tested.

[0033] Beneficial effects:

[0034] (1) Since surface-enhanced Raman spectroscopy can significantly enhance Raman scattering signals, making originally weak molecular vibration information detectable; the weak value amplification effect introduces a post-selection process, amplifying the change value of the system's observed values, which makes it easy to combine weak value amplification technology with surface-enhanced Raman spectroscopy detection technology and optimize the system's performance; therefore, this invention combines the enhancement characteristics of surface-enhanced Raman spectroscopy with the post-selection of weak value amplification technology, which can further amplify these weak signals, achieve further enhancement of weak Raman signals, thereby improving the sensitivity of the detection method and achieving accurate detection of low-concentration substances; this spectroscopic detection method that combines the two effects is expected to provide more efficient and accurate detection methods for fields such as chemistry, biology, and medicine.

[0035] (2) By introducing a quarter-wave plate I, a quarter-wave plate II and a polarizer II, the present invention introduces a post-selection process with weak value amplification effect, which helps to extract useful signals from complex background noise, thereby improving the resolution of spectral detection; this makes the detection device more accurate in distinguishing similar substances or analyzing complex mixtures.

[0036] (3) By controlling the forward and backward movement of the spherical lens, the present invention controls the number of focal points and the energy of the focusing on the sample to be tested, thereby enabling the detection of different types of samples to be tested.

[0037] (4) Compared with traditional spectroscopic detection methods, the method of this invention based on surface-enhanced Raman spectroscopy and weak amplification effect may not require complex sample pretreatment processes and requires less sample volume. Furthermore, due to its high sensitivity and resolution, this method can achieve real-time dynamic monitoring of target substances. The spectroscopic detection method based on surface-enhanced Raman spectroscopy and weak amplification effect has significant beneficial effects in enhancing detection sensitivity, improving resolution, broadening application range, and realizing real-time dynamic monitoring. Attached Figure Description

[0038] Figure 1 This is a structural diagram of the spectral detection device of the present invention;

[0039] Among them, 01-Laser; 02-Collimating lens; 03-Gaussian filter; 04-Polarizer I; 05-Beam splitter prism; 06-Spherical lens I; 07-Parametric lens I; 08-Reflecting mirror; 09-Parametric lens II; 010-Trapezoidal prism; 011-Sample to be tested; 012-Focusing lens I; 013-Cemented lens; 014-Focusing lens II; 015-Spherical lens II; 016-Collimator I; 017-Collimator II; 018-Filter; 019-Quarter-wave plate I; 020-Quarter-wave plate II; 021-Polarizer II; 022-Coupled lens; 023-Spectrometer; 024-Computer; 025-Displacement control drive. Detailed Implementation

[0040] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0041] Example 1:

[0042] This embodiment provides a spectroscopic detection device based on surface-enhanced Raman spectroscopy and weak-value amplification effect. See attached document. Figure 1 The spectral detection device includes: a laser 01, a reflective lens module, a trapezoidal prism 010, a refractive lens module, a spectrometer 023, and a computer 024.

[0043] The trapezoidal prism 010 is a prism with a trapezoidal cross-section. The upper and lower end faces of the trapezoidal prism 010 are uncoated, while the other four different surfaces of the trapezoidal prism 010 are coated with corresponding dielectric films. Specifically, the two side faces (i.e., the waists of the trapezoid) of the trapezoidal prism 010 are coated with an anti-reflection film for incident light and an anti-reflection film for Raman scattered light; the front surface (upper base of the trapezoid) of the trapezoidal prism 010 is coated with an anti-reflection film for incident light and an anti-reflection film for Raman scattered light; and the rear surface (lower base of the trapezoid) of the trapezoidal prism 010 is coated with an anti-reflection film for incident light and an anti-reflection film for Raman scattered light.

[0044] The test sample 011 uses a microfluidic chip and has a reinforcing substrate material; the test sample 011 is in close contact with the rear surface of the trapezoidal prism 010.

[0045] The laser 01 is used to emit a laser beam. After being collimated, filtered, polarized, split, and reflected by the reflective lens module, the laser beam forms incident light that enters from two sides of the trapezoidal prism 010. The incident light undergoes multiple reflections within the trapezoidal prism 010, causing multiple focal points to be simultaneously focused onto the rear surface of the trapezoidal prism 010, so that the light energy can be fully concentrated to excite the Raman spectrum.

[0046] The incident light is focused onto the sample 011 to be tested. The reinforcing substrate material on the sample 011 is excited by the incident light to generate a surface-enhanced Raman spectrum, i.e. Raman scattered light.

[0047] The generated Raman scattered light passes through the front surface of the trapezoidal prism 010 and is incident on the refractive lens module. After being focused, collimated, refocused, filtered, polarization-state converted, polarized, and coupled by the refractive lens module, the Raman scattered light forms the outgoing light and enters the spectrometer 023. The spectrometer 023 transmits the raw spectral information data of the outgoing light (i.e., the surface-enhanced Raman spectrum data) to the computer 024. The computer 024 performs quantitative and qualitative processing, analysis, and real-time display on the sample 011 to be tested based on the data, obtains the concentration information of the sample 011 to be tested, and determines the type of substance in the sample 011 to be tested, thus completing the detection of the sample 011 to be tested.

[0048] The reflective lens module includes: a collimating lens 02, a Gaussian filter 03, a polarizer 04, a beam splitter 05, a spherical lens 06, a parabolic mirror 07, a reflecting mirror 08, and a parabolic mirror 09.

[0049] The collimating lens 02, Gaussian filter 03, polarizer 04, beam splitter 05, and spherical lens 06 are sequentially distributed between the laser 01 and the trapezoidal prism 010. The optical axes of the collimating lens 02, Gaussian filter 03, polarizer 04, and beam splitter 05 are aligned. The reflecting mirror 08 and spherical lens 06 are located on two mutually perpendicular emission directions of the beam splitter 05. The spherical surface of spherical lens 06 is opposite to the beam splitter 05. The optical axis of spherical lens 06 is located between the optical axis of the beam splitter 05 and the optical axis of the reflecting mirror 08, and the optical axis of spherical lens 06 is aligned with the optical axis of the trapezoidal prism 010. Parabolic mirrors 07 and 09 are located on both sides of spherical lens 06 and are symmetrically arranged along the optical axis of spherical lens 06. The parabolic surfaces of parabolic mirrors 07 and 09 are opposite to the spherical surface of spherical lens 06.

[0050] The laser beam generated by the laser 01 is collimated by the collimating lens 02, filtered by the Gaussian filter 03, and then polarized by the polarizer 04. The polarized output beam is split into two beams by the beam splitter 05. One beam goes directly to the spherical lens 06, and the other beam is reflected by the mirror 08 and then goes to the spherical lens 06. The two beams that reach the spherical lens 06 are symmetrically arranged along the optical axis of the spherical lens 06. After being reflected again by the spherical surface of the spherical lens 06, the two beams go to the parabolic mirror 07 and the parabolic mirror 09, respectively. The light reflected by the parabolic surfaces of the parabolic mirrors 07 and 09 forms incident light that enters from the two sides of the trapezoidal prism 010.

[0051] The refractive lens module includes: a focusing lens 012, a cemented lens 013, a focusing lens 014, a spherical lens 015, a collimator 016, a collimator 017, a filter 018, a quarter-wave plate 019, a quarter-wave plate 020, a polarizer 021, and a coupling lens 022.

[0052] The focusing lens 012, cemented lens 013, focusing lens 014, spherical lens 015, and collimator 016 are sequentially distributed between the trapezoidal prism 010 and the spherical lens 06, and the optical axes of the focusing lens 012, cemented lens 013, focusing lens 014, spherical lens 015, and collimator 016 are aligned with the optical axis of the trapezoidal prism 010; collimator 016 and collimator 017 are connected by optical fiber.

[0053] The collimator 2 017, filter 018, quarter-wave plate 1 019, quarter-wave plate 2 020, polarizer 2 021 and coupling lens 022 have the same optical axis and are distributed in sequence; among them, the coupling lens 022 is located closest to the spectrometer 023.

[0054] Raman scattered light transmitted from the front surface of trapezoidal prism 010 is focused by focusing lens 012, collimated by cemented lens 013, and then focused again by focusing lens 014. The focused Raman scattered light is transmitted through spherical lens 2015 and focused onto collimator 016. Collimator 016 transmits the light beam to collimator 2017 via optical fiber. The light beam exiting from collimator 2017 is filtered by filter 018, and then sequentially passes through quarter-wave plate 019, quarter-wave plate 2020, and polarizer 2021 for polarization state conversion. Finally, it is coupled by coupling lens 022 to form outgoing light, which enters spectrometer 023. Quarter-wave plate 019 and quarter-wave plate 2020 are used to adjust the angle of the polarized light after polarization by polarizer 2021.

[0055] The spectral detection device has a pre-selection state and a post-selection state, which are jointly implemented by waveplates and polarizers. Specifically, the pre-selection process of the pre-selection state of the spectral detection device is determined by polarizer 04, and the post-selection process of the post-selection state of the spectral detection device is determined by quarter-wave plate 019, quarter-wave plate 020, and polarizer 021. The weak value amplification effect of the spectral detection device is achieved by introducing the post-selection state. By adjusting the poses of quarter-wave plate 019 and quarter-wave plate 020, the post-selection state and the pre-selection state are made nearly orthogonal. This means that when the polarized light emitted from polarizer 04 is orthogonal to the polarized light emitted from polarizer 021, the observed value can be amplified, making it much larger than the eigenvalue.

[0056] In a preferred embodiment, the spectral detection device further includes a displacement control drive 025. The computer 024 controls the forward and backward movement of the spherical lens 06 based on the characteristics of the sample 011 to be tested, such as the required light energy intensity and scattered light intensity of the sample 011, thereby controlling the number of focal points focused on the sample 011 and the amount of focused energy. The displacement control drive 025 is also used to monitor the displacement of the spherical lens 06 and feed it back to the computer 024.

[0057] Example 2:

[0058] Based on the spectral detection device of Example 1, this embodiment provides a spectral detection method based on surface-enhanced Raman spectroscopy and weak-value amplification effect. The specific steps of this method are as follows:

[0059] Step 1: Deposit corresponding dielectric films on different surfaces of the trapezoidal prism 010 of the spectral detection device; the two sides (i.e., the waists of the trapezoid) of the trapezoidal prism 010 are coated with an anti-reflection film for incident light and an anti-reflection film for Raman scattered light; the front surface (upper base of the trapezoid) of the trapezoidal prism 010 is coated with an anti-reflection film for incident light and an anti-reflection film for Raman scattered light; the rear surface (lower base of the trapezoid) of the trapezoidal prism 010 is coated with an anti-reflection film for incident light and an anti-reflection film for Raman scattered light.

[0060] Step 2: Fix the sample to be tested 011 tightly to the back surface of the trapezoidal prism 010. The two can be fixed by means of mechanical tooling, but not limited to mechanical tooling.

[0061] Step 3: Using a prism-based reflective lens module in conjunction with a trapezoidal prism 010, multiple focal points can be simultaneously focused onto the rear surface of the trapezoidal prism 010 through the multiple reflection characteristics of the trapezoidal prism 010. The light energy is fully concentrated on the rear surface of the trapezoidal prism 010 to excite the sample 011 to generate a surface-enhanced Raman spectrum, i.e., Raman scattering light.

[0062] Meanwhile, the collection of scattered Raman light is achieved by using a prism-based refractive lens module, and the optical design that takes into account both angular excitation and directional radiation collection greatly improves the energy of the surface-enhanced Raman spectrum.

[0063] When a surface-enhanced Raman spectrum is generated on the sample 011, a spectral change is introduced into the optical path of the spectral detection device. This spectral change can be amplified by the spectral detection device, thereby achieving a weak coupling state of the spectral detection device.

[0064] The amplification is achieved by introducing a post-selection state to realize a weak value amplification effect. The magnitude of the weak value is determined by the pre- and post-selection states. The pre- and post-selection states of the spectral detection device are jointly realized by waveplates and polarizers. Specifically, the reflective lens module includes polarizer 04, and the refractive lens module includes quarter-wave plate 019, quarter-wave plate 020, and polarizer 021. The pre-selection process of the pre-selection state of the spectral detection device is determined by polarizer 04, and the post-selection process of the post-selection state of the spectral detection device is determined by polarizer 021. Quarter-wave plate 019 and quarter-wave plate 020 are used to adjust the phase difference between the horizontal and vertical polarization components to achieve high-precision measurement. In this embodiment, by adjusting the rotation angle of quarter-wave plate 019 and quarter-wave plate 020, when the post-selection state and the pre-selection state are orthogonal, that is, when the polarized light emitted from polarizer 1 is orthogonal to the polarized light emitted from polarizer 2, the observed value can be amplified to be much larger than the eigenvalue.

[0065] During the detection process, the change in refractive index of the sample 011 at the total internal reflection interface of the trapezoidal prism 010 alters the phase difference between the two polarization components. This phase difference is determined by the shift in the center wavelength of the output spectrum. This phase difference change can be amplified by the system, thereby enabling the detection of the physical quantity causing the change in refractive index of the sample 011. The change in refractive index causes a change in the Raman spectral intensity. When measuring the Raman spectral intensity, the Raman spectral intensity of the sample 011 is related to its refractive index n, meaning that the refractive index of the sample 011 affects the Raman spectral intensity, thus affecting the accuracy of quantitative analysis. According to perturbation theory, the scattering cross section of Raman scattering can be expressed by the following formula:

[0066]

[0067] In the formula, σ is the scattering cross section, n is the refractive index of the sample, λ is the wavelength of the incident light, NA is Avogadro's constant, α is the polarizability of the sample, and Γ(ω) is the spectral shape function of the Raman scattered light.

[0068] The Raman spectral intensity can be calculated by calculating the scattering cross section. The relationship between Raman spectral intensity and scattering cross section is given by the following formula:

[0069]

[0070] In the formula, I is the scattering intensity, I0 is the intensity of the laser, λ is the wavelength of the incident light, r is the distance between the front surface of the sample 011 and the optical center of the focusing lens 012, and c is the speed of light. The front surface of the sample 011 is the surface on which the sample 011 and the trapezoidal prism 010 are attached.

[0071] Step 4: The spectrometer transmits the raw spectral information of the collected scattered Raman light to the computer 024. The computer 024 performs quantitative and qualitative processing, analysis and real-time display on the sample 011 to be tested based on the data, obtains the concentration information of the sample 011 to be tested and determines the type of substance in the sample 011 to be tested, and completes the detection of the sample 011 to be tested.

[0072] Simultaneously, the computer 024 transmits control signals to the displacement control drive 025. The displacement control drive 025 controls the spherical lens 06 to move back and forth according to the control signals. By changing the position of the light beam incident on the parabolic mirror 07 and parabolic mirror 09, the number of focal points focused on the rear surface of the trapezoidal prism 010 is adjusted, thereby changing the incident light intensity and incident light power density, and realizing the detection of different types of test samples 010.

[0073] In summary, the above are merely preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A spectroscopic detection device based on surface-enhanced Raman spectroscopy and weak-value amplification effect, characterized in that, The spectral detection device includes: a laser, a reflective lens module, a trapezoidal prism, a refractive lens module, a spectrometer, and a computer; The sample to be tested has a reinforcing substrate material; the sample to be tested is attached to the back surface of the trapezoidal prism; The laser emits a laser beam, which is collimated, filtered, polarized, split, and reflected by a reflective lens module to form incident light that enters from two sides of a trapezoidal prism. The incident light undergoes multiple reflections within the trapezoidal prism, causing multiple focal points to be simultaneously focused onto the rear surface of the trapezoidal prism, and then onto the sample under test. The reinforcing substrate material on the sample under test is excited by the incident light to generate surface-enhanced Raman spectra, i.e., Raman scattering light. The generated Raman scattered light passes through the front surface of the trapezoidal prism and enters the refractive lens module. After being focused, collimated, refocused, filtered, polarization-state converted, polarized, and coupled by the refractive lens module, the Raman scattered light forms the outgoing light and enters the spectrometer. The spectrometer transmits the raw spectral information of the outgoing light to the computer. The computer processes and analyzes the sample to obtain the concentration information of the sample and determines the type of substance in the sample, thus completing the detection of the sample.

2. The spectroscopic detection device based on surface-enhanced Raman spectroscopy and weak-value amplification effect as described in claim 1, characterized in that, The trapezoidal prism is a prism with a trapezoidal cross-section. The two sides of the trapezoidal prism are coated with an anti-reflection coating for incident light and an anti-reflection coating for Raman scattered light. The front surface of the trapezoidal prism is coated with an anti-reflection coating for incident light and an anti-reflection coating for Raman scattered light. The rear surface of the trapezoidal prism is coated with an anti-reflection coating for incident light and an anti-reflection coating for Raman scattered light.

3. The spectroscopic detection device based on surface-enhanced Raman spectroscopy and weak-value amplification effect as described in claim 2, characterized in that, The reflective lens module includes: a collimating lens, a Gaussian filter, a polarizer, a beam splitter, a spherical lens, a parabolic lens, a reflecting mirror, and a parabolic lens. The collimating lens, Gaussian filter, polarizer one, beam splitter, and spherical lens one are sequentially distributed between the laser and the trapezoidal prism. The optical axes of the collimating lens, Gaussian filter, polarizer one, and beam splitter are aligned. The reflecting mirror and spherical lens one are located on two mutually perpendicular exit directions of the beam splitter. The spherical surface of spherical lens one faces the beam splitter. The optical axis of spherical lens one is located between the optical axis of the beam splitter and the optical axis of the reflecting mirror, and it is aligned with the optical axis of the trapezoidal prism. Parabolic mirror one and parabolic mirror two are located on either side of spherical lens one and are symmetrically arranged along its optical axis. The parabolic surfaces of parabolic mirror one and parabolic mirror two face the spherical surface of spherical lens one. The laser beam generated by the laser is collimated by a collimating lens, filtered by a Gaussian filter, and then polarized by a polarizer. The polarized beam is then split into two beams by a beam splitter. One beam goes directly to a spherical lens, while the other beam is reflected by a mirror and then goes to a spherical lens. The two beams that reach the spherical lens are symmetrically arranged along the optical axis of the spherical lens. After being reflected by the spherical surface of the spherical lens, the two beams go to a parabolic mirror and a parabolic mirror, respectively. The light reflected by the parabolic surfaces of the parabolic mirrors forms incident light that enters from the two sides of the trapezoidal prism.

4. The spectroscopic detection device based on surface-enhanced Raman spectroscopy and weak-value amplification effect as described in claim 3, characterized in that, The refractive lens module includes: a focusing lens 1, a cemented lens, a focusing lens 2, a spherical lens 2, a collimator 1, a collimator 2, a filter, a quarter-wave plate 1, a quarter-wave plate 2, a polarizer 2, and a coupling lens; The focusing lens 1, cemented lens, focusing lens 2, spherical lens 2, and collimator 1 are sequentially distributed between the trapezoidal prism and the spherical lens 1, and the optical axes of the focusing lens 1, cemented lens, focusing lens 2, spherical lens 2, and collimator 1 are aligned with the optical axis of the trapezoidal prism; the collimator 1 and collimator 2 are connected by an optical fiber. The collimator II, filter, quarter-wave plate I, quarter-wave plate II, polarizer II, and coupling lens have the same optical axis and are distributed in sequence; among them, the coupling lens is located closest to the spectrometer. Raman scattered light transmitted from the front surface of the trapezoidal prism is focused by focusing lens one, collimated by a cemented lens, and then focused again by focusing lens two. The focused Raman scattered light is then transmitted through spherical lens two and focused onto collimator one. Collimator one transmits the light beam to collimator two through an optical fiber. The light beam exiting collimator two is filtered by a filter, then passes through quarter-wave plate one, quarter-wave plate two, and polarizer two in sequence for polarization state conversion. Finally, it is coupled by a coupling lens to form the outgoing light, which then enters the spectrometer. Quarter-wave plate one and quarter-wave plate two are used to adjust the angle of the polarized light after polarization by polarizer two.

5. A spectroscopic detection device based on surface-enhanced Raman spectroscopy and weak-value amplification effect as described in claim 3 or 4, characterized in that, The spectral detection device also includes a displacement control drive. The computer controls the forward and backward movement of the spherical lens one through the displacement control drive, changes the position of the light beam incident on the parabolic mirror one and the parabolic mirror two, and thus controls the number of focal points focused on the sample to be tested and the amount of focused energy.

6. A detection method for a spectroscopic detection device based on surface-enhanced Raman spectroscopy and weak-value amplification effect according to any one of claims 1-5, characterized in that, The specific steps of this detection method are as follows: Step 1: Coat different surfaces of the trapezoidal prism of the spectral detection device with corresponding dielectric films; the coatings on the two sides of the trapezoidal prism are anti-reflection coatings for incident light and anti-reflection coatings for Raman scattered light; the coatings on the front surface of the trapezoidal prism are anti-reflection coatings for incident light and anti-reflection coatings for Raman scattered light; the coatings on the back surface of the trapezoidal prism are anti-reflection coatings for incident light and anti-reflection coatings for Raman scattered light. Step 2: Fit and fix the sample to be tested onto the back surface of the trapezoidal prism; Step 3: Using a prism-based reflective lens module in conjunction with a trapezoidal prism, the multiple reflection characteristics of the trapezoidal prism allow multiple focal points to be simultaneously focused onto the rear surface of the trapezoidal prism. The light energy is fully concentrated on the rear surface of the trapezoidal prism to excite the sample to generate surface-enhanced Raman spectra, i.e., Raman scattered light. At the same time, the scattered Raman light is collected using a prism-based refractive lens module. Specifically, when a surface-enhanced Raman spectrum is generated on the sample to be tested, a spectral change is introduced into the optical path of the spectral detection device, and this spectral change is amplified by the spectral detection device; the amplification is achieved by introducing a post-selective state to achieve a weak value amplification effect; the magnitude of the weak value is determined by the pre- and post-selective states, and the pre- and post-selective states of the spectral detection device are jointly achieved by a waveplate and a polarizer; Step four: The spectrometer transmits the raw spectral information of the collected scattered Raman light to the computer. The computer then performs quantitative and qualitative processing, analysis, and real-time display of the data to obtain the concentration information of the sample and determine the type of substance in the sample, thus completing the detection of the sample.

7. The detection method as described in claim 6, characterized in that, In step three, the pre- and post-selection states of the spectral detection device are achieved by a polarizer, as follows: The reflective lens module includes polarizer one, and the refractive lens module includes quarter-wave plate one, quarter-wave plate two, and polarizer two. The pre-selection process of the pre-selection state of the spectral detection device is determined by polarizer one, and the post-selection process of the post-selection state of the spectral detection device is determined by polarizer two. Quarter-wave plate one and quarter-wave plate two are used to adjust the phase difference between the horizontal and vertical polarization components. By adjusting the rotation angle of quarter-wave plate one and quarter-wave plate two, when the post-selection state and the pre-selection state are orthogonal, that is, when the polarized light emitted from polarizer one is orthogonal to the polarized light emitted from polarizer two, the observed value can be amplified to be greater than the eigenvalue.

8. The detection method as described in claim 6, characterized in that, In step four, the computer transmits control signals to the displacement control drive. The displacement control drive controls the spherical lens in the reflective lens module to move back and forth according to the control signals, thereby adjusting the number of focal points focused on the rear surface of the trapezoidal prism, so as to change the incident light intensity and incident light power density, and realize the detection of different types of samples to be tested.

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