Single molecule raman signal light field modulation enhancement methods, systems, media, and products

Abstract

The application discloses a single-molecule Raman signal light field modulation enhancement method, system, medium and product, relates to the technical field of single-molecule Raman detection, and the method comprises the following steps: acquiring current capture parameters of a target single molecule in a to-be-detected sample in a current light field area collected by a single-molecule capture module; acquiring a current Raman scattering signal of the target single molecule in the current light field area collected by a Raman signal collection module; determining a matching condition of the current light field area and the target single molecule according to the current Raman scattering signal and the current capture parameters; and determining an adjustable working parameter according to the matching condition of the current light field area and the target single molecule, and adjusting the working parameter. The application realizes accurate detection of a single-molecule Raman signal.

Description

Technical Field

[0001] This application relates to the field of single-molecule Raman detection technology, and in particular to methods, systems, media, and products for single-molecule Raman signal optical field modulation and enhancement. Background Technology

[0002] Single-molecule Raman spectroscopy has become a core technology in the field of single-molecule detection due to its ability to provide accurate information such as the chemical structure, vibrational modes, and device on / off ratios of molecules. This technology can directly acquire the inherent fingerprint information of target molecules without labeling, and has significant application value in fields such as biomedicine, materials science, surface catalysis, and quantum devices.

[0003] However, Raman scattering is essentially an inelastic scattering process with an extremely small scattering cross-section, much smaller than that of fluorescence scattering. When the target is reduced to a single molecule, the resulting single-molecule Raman signal is extremely weak and easily overwhelmed by environmental noise, substrate background, and stray light, making it difficult to efficiently capture and identify the single-molecule Raman signal. Existing methods for enhancing single-molecule Raman signals through optical field modulation are generally static modulation or single-dimensional dynamic modulation, which lacks modulation flexibility and specificity, making it difficult to adapt to the random distribution and dynamic motion characteristics of single molecules. This results in low optical field modulation efficiency and fails to fully utilize the enhancement effect of the optical field. Summary of the Invention

[0004] The main objective of this application is to provide a method, system, medium, and product for enhancing the optical field modulation of single-molecule Raman signals, aiming to solve the technical problem that the modulation efficiency of existing optical field modulation techniques for single-molecule Raman signals is low, resulting in inaccurate detection of single-molecule Raman signals.

[0005] This application provides a method for modulating and enhancing the optical field of a single-molecule Raman signal. The method is applied to a single-molecule Raman signal modulation and enhancement system, which includes a single-molecule capture module and a Raman signal acquisition module. The method includes: The current capture parameters of the target single molecule in the sample under test in the current light field region are obtained from the single molecule capture module. Acquire the current Raman scattering signal of the target single molecule in the current optical field region, acquired by the Raman signal acquisition module; Based on the current Raman scattering signal and the current capture parameters, determine the matching status between the current optical field region and the target single molecule; Based on the matching between the current light field region and the target single molecule, the working parameters to be adjusted are determined and then adjusted.

[0006] In one feasible embodiment, the single-molecule capture module includes: a scanning probe assembly, a nanocavity structure, and a piezoelectric control assembly, wherein the scanning probe assembly includes a scanning tunneling microscope tip, and prior to the step of acquiring the current capture parameters of the target single molecule in the current light field region of the sample acquired by the single-molecule capture module, the module further includes: The initial capture parameters of the single-molecule capture module are determined based on the preset characteristic parameters of the target single molecule. Based on the initial capture parameters, a nano-gap is formed between the scanning tunneling microscope tip and the nanocavity structure to obtain the current light field region; The piezoelectric control component is controlled to move the target single molecule to the current light field region.

[0007] In one feasible embodiment, the single-molecule Raman signal optical field modulation enhancement system further includes an optical field excitation module, which, after the step of controlling the piezoelectric control component to move the target single molecule to the current optical field region, further includes: The initial light field parameters are determined based on the preset characteristic parameters of the target single molecule; The optical field excitation module is controlled to generate excitation light according to the initial optical field parameters and apply it to the sample to be tested.

[0008] In a feasible embodiment, the step of determining the operating parameters to be adjusted based on the matching between the current light field region and the target single molecule includes: If the current capture parameter is less than a preset capture parameter threshold, the working parameter to be adjusted is determined to be the current capture parameter. If the current Raman scattering signal is less than a preset Raman signal threshold, the operating parameter to be adjusted is determined to be the current optical field parameter. If the current capture parameter is less than the capture parameter threshold and the current Raman scattering signal is less than the Raman signal threshold, the operating parameters to be adjusted are determined to be the current capture parameter and the current optical field parameter.

[0009] In one feasible embodiment, the operating parameters include the current capture parameters, which include the tunneling current signal, the current spacing of the nano-gap, and the current position of the scanning tunneling microscope tip; the capture parameter threshold includes a current signal threshold; and the step of adjusting the operating parameters includes: The adjustment value of the current spacing is determined based on the intensity change of the current Raman scattering signal; A region search is performed centered on the current position of the scanning tunneling microscope tip to determine the current position offset of the scanning tunneling microscope tip, and a position compensation value is determined based on the current position offset. The single-molecule capture module is controlled to adjust according to the adjustment value and the position compensation value, so that the adjusted tunneling current signal is greater than or equal to the current signal threshold.

[0010] In a feasible embodiment, the single-molecule Raman signal light field modulation enhancement system further includes a light field modulation module, wherein the current light field parameters include at least one of spatial phase, spatial amplitude, polarization state, and time gating, the operating parameters include the current light field parameters, and the step of adjusting the operating parameters includes: When the tunnel current signal is greater than or equal to the current signal threshold, the optical field modulation module is controlled to adjust the polarization state of the excitation light to match the transition dipole moment direction of the target single molecule; When the signal-to-noise ratio of the current Raman scattering signal decreases, the optical field modulation module is controlled to adjust the spatial phase and spatial amplitude of the excitation light to suppress sidelobes; When the background noise of the current Raman scattering signal increases, the optical field modulation module is controlled to adjust the acquisition time window to suppress background interference.

[0011] In one feasible embodiment, the Raman signal acquisition module includes: a near-field acquisition probe and a far-field acquisition component, and the step of acquiring the current Raman scattering signal of the target single molecule in the current optical field region acquired by the Raman signal acquisition module includes: Acquire the first Raman scattering signal of the near-field region of the target single molecule collected by the near-field acquisition probe; Acquire the second Raman scattering signal of the far-field region of the target single molecule acquired by the far-field acquisition component; The current Raman scattering signal is determined based on the first Raman scattering signal and the second Raman scattering signal.

[0012] This application embodiment also provides a single-molecule Raman signal optical field modulation and enhancement system, the single-molecule Raman signal optical field modulation and enhancement system comprising: Single-molecule capture module; Raman signal acquisition module; The control module is communicatively connected to both the single-molecule capture module and the Raman signal acquisition module, and is used to execute the steps of the single-molecule Raman signal light field modulation enhancement method described above.

[0013] This application embodiment also provides a storage medium, which is a computer-readable storage medium, and stores a computer program on the storage medium. When the computer program is executed by a processor, it implements the steps of the single-molecule Raman signal light field modulation enhancement method as described above.

[0014] This application also provides a computer program product, which includes a computer program that, when executed by a processor, implements the steps of the single-molecule Raman signal light field modulation enhancement method described above.

[0015] The present application proposes one or more technical solutions, which have at least the following technical effects: The single-molecule Raman signal light field modulation enhancement method is applied to a single-molecule Raman signal light field modulation enhancement system, which includes a single-molecule capture module and a Raman signal acquisition module. First, the current capture parameters of the target single molecule in the test sample within the current light field region are acquired by the single-molecule capture module; the current Raman scattering signal of the target single molecule within the current light field region is acquired by the Raman signal acquisition module; this allows for the perception of the real-time state of the target single molecule from two dimensions: light field-molecule coupling and molecular spatial positioning accuracy, providing a complete data foundation for subsequent accurate judgment. Then, based on the current Raman scattering signal and the current capture parameters, the matching status between the current light field region and the target single molecule is determined; based on the matching status between the current light field region and the target single molecule, the operating parameters to be adjusted are determined and then adjusted. By comprehensively analyzing the two signals, the modules and corresponding parameters requiring adjustment are precisely determined. This overcomes the limitation of existing technologies that use a single control method to simultaneously address multiple optical field mismatches in single-molecule Raman detection. The adjusted optical field region continuously matches the real-time state of the target single molecule, significantly improving the accuracy of single-molecule Raman signal detection. Therefore, this embodiment achieves accurate detection of single-molecule Raman signals through a closed-loop control process that enhances the optical field modulation signal. Attached Figure Description

[0016] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0017] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1This is a schematic flowchart of the single-molecule Raman signal optical field modulation enhancement method involved in the embodiments of this application; Figure 2 These are Raman spectra of the single-molecule Raman signal before and after modulation enhancement according to embodiments of this application. Figure 3 This is a modulation diagram of the optical field modulation module involved in an embodiment of this application; Figure 4 This is a simplified flowchart illustrating the single-molecule Raman signal optical field modulation enhancement method according to an embodiment of this application. Figure 5 This is a schematic diagram of the structure of the single-molecule Raman signal optical field modulation and enhancement system according to an embodiment of this application; Figure 6 This is a schematic diagram of the device structure of the hardware operating environment involved in the single-molecule Raman signal optical field modulation enhancement method in the embodiments of this application.

[0019] The purpose, features, and advantages of this application will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0020] It should be understood that the specific embodiments described herein are merely illustrative of the technical solutions of this application and are not intended to limit this application.

[0021] To better understand the technical solution of this application, a detailed description will be provided below in conjunction with the accompanying drawings and specific implementation methods.

[0022] In this embodiment, for ease of description, the following description uses a single-molecule Raman signal light field modulation and enhancement device as the main execution subject.

[0023] Because existing methods for enhancing single-molecule Raman signals through optical field modulation are generally static modulation or single-dimensional dynamic modulation, they have poor modulation flexibility and are not targeted enough. They are difficult to adapt to the random distribution and dynamic motion characteristics of single molecules, resulting in low optical field modulation efficiency and failing to fully utilize the enhancement effect of optical field.

[0024] This application provides a solution for a single-molecule Raman signal light field modulation enhancement method applied to a single-molecule Raman signal light field modulation enhancement system. The single-molecule Raman signal light field modulation enhancement system includes a single-molecule capture module and a Raman signal acquisition module. First, the current capture parameters of the target single molecule in the test sample within the current light field region are acquired by the single-molecule capture module; the current Raman scattering signal of the target single molecule within the current light field region is acquired by the Raman signal acquisition module. This allows for the perception of the real-time state of the target single molecule from two dimensions: light field-molecule coupling and molecular spatial positioning accuracy, providing a complete data foundation for subsequent accurate judgment. Then, based on the current Raman scattering signal and current capture parameters, the matching status between the current light field region and the target single molecule is determined; based on the matching status between the current light field region and the target single molecule, the operating parameters to be adjusted are determined and then adjusted. By comprehensively analyzing the two signals, the modules and corresponding parameters requiring adjustment are precisely determined. This overcomes the limitation of existing technologies that use a single control method to simultaneously address multiple optical field mismatches in single-molecule Raman detection. The adjusted optical field region continuously matches the real-time state of the target single molecule, significantly improving the accuracy of single-molecule Raman signal detection. Therefore, this embodiment achieves accurate detection of single-molecule Raman signals through a closed-loop control process that enhances the optical field modulation signal.

[0025] It should be noted that the executing entity in this embodiment can be a computing service device with data processing, network communication, and program execution functions, such as a tablet computer, personal computer, or mobile phone, or an electronic device capable of performing the above functions, such as a single-molecule Raman signal light field modulation and enhancement device. The following description uses a single-molecule Raman signal light field modulation and enhancement device as an example to illustrate this embodiment and the subsequent embodiments.

[0026] Based on this, embodiments of this application provide a method for modulating and enhancing the optical field of a single-molecule Raman signal, referring to... Figure 1 In this embodiment, the single-molecule Raman signal light field modulation and enhancement method is applied to a single-molecule Raman signal light field modulation and enhancement system. The single-molecule Raman signal light field modulation and enhancement system includes a single-molecule capture module and a Raman signal acquisition module. The single-molecule Raman signal light field modulation and enhancement method includes steps S10 to S40: Step S10: Obtain the current capture parameters of the target single molecule in the sample under test in the current light field region, as collected by the single molecule capture module; In one feasible embodiment, in order to assess whether the target single molecule is effectively and stably bound in the current light field region, the current capture parameters in the current light field region are obtained.

[0027] The current capture parameters refer to the parameters output by the single-molecule capture module, which characterize whether a single molecule is stably confined within the current light field region.

[0028] In another feasible implementation, the single-molecule capture module includes: a scanning probe assembly, a nanocavity structure, and a piezoelectric control assembly, wherein the scanning probe assembly includes a scanning tunneling microscope tip, and prior to step S10, which acquires the current capture parameters of the target single molecule in the current light field region of the sample acquired by the single-molecule capture module, the module further includes: Step S01: Determine the initial capture parameters of the single molecule capture module based on the preset characteristic parameters of the target single molecule; In one feasible embodiment, before the formal excitation detection begins, the capture module is initialized in a personalized and differentiated manner based on the individual characteristics of the target single molecule. This allows key parameters such as the tip position and nanocavity structure to be adapted to the optimal excitation conditions for different molecules. This avoids the problem of poor initial matching caused by using uniform static preset values, which requires long-term dynamic adjustment to enter a stable detection state. As a result, the warm-up time for the system to enter efficient detection is shortened, and the overall detection efficiency and initial signal quality of the target single molecule in the sample to be tested are improved.

[0029] The preset characteristic parameters of the target single molecule refer to the characteristic data related to the physicochemical properties of the target single molecule that are known in advance, including the excitation energy level characteristics of the molecule, polarizability anisotropy, molecular size, and local plasmon resonance peak of the near-field enhancement structure. The preset characteristic parameters can be obtained in advance through theoretical calculations, literature data, pre-experiments or standard calibration sample calibration and stored in the system database.

[0030] Step S02: Based on the initial capture parameters, control the formation of a nano-gap between the scanning tunneling microscope tip and the nanocavity structure to obtain the current light field region; In one feasible embodiment, a nano-gap formed by a tip-nanocavity structure is used to generate an extremely strong local electromagnetic field, i.e., a hot spot, which greatly enhances the Raman scattering signal of single molecules adsorbed in the region.

[0031] The tip of an STM (Scanning Tunneling Microscope) is an extremely fine metal probe made of noble metals such as Au, Ag, or Pt, with a tip curvature radius on the nanometer scale. In scanning tunneling microscopy, it is used to apply tunneling currents or generate localized electromagnetic fields on the sample surface, constructing nanoscale optical field enhancement structures.

[0032] A nanocavity structure is a metal or dielectric structure with nanoscale cavities or gaps. It is usually a small hole on a metal thin film, a pair of metal nanoparticles, or a metal substrate opposite to the tip. Together with the tip, it forms a plasma resonant cavity of "tip-substrate" or "tip-nanocavity".

[0033] The nanogap refers to the extremely small distance between the tip of a scanning tunneling microscope probe and the surface of a nanocavity structure, which can form an extremely strong local electromagnetic field, i.e., a hot spot region.

[0034] A piezoelectric control assembly is a driving device used to control the height and horizontal position of the STM tip, as well as the spacing of the nanocavity structures, to achieve precise electronic modulation of the local range and intensity of the optical field. The piezoelectric control assembly includes a piezoelectric ceramic displacement stage and a displacement control unit, with a positioning accuracy of up to 0.1 nm.

[0035] Step S03: Control the piezoelectric control component to move the target single molecule to the current light field region.

[0036] The surface of the sample to be tested is usually randomly covered with a large number of molecules. In order to place specific single molecules in the nano gaps to enhance the light field, they must be physically moved in a controlled manner.

[0037] Place the prepared sample on the sample stage and adjust the position of the sample stage so that the target detection area is aligned with the target light field area formed by the scanning tunneling microscope tip and the nanocavity structure, and at the same time aligned with the output light path of the light field excitation module and the collection light path of the Raman signal collection module.

[0038] Optionally, the radius of curvature of the STM tip is ≤10 nm, and the size of the nano-gap is 1 nm to 10 nm.

[0039] The smaller the radius of curvature of the STM tip, the greater the enhancement factor of the local electric field generated near its tip. Only when the radius of curvature is ≤10 nm can the tip concentrate the energy of the incident laser into an extremely small hot spot. If the tip radius exceeds 10 nm, the hot spot region will diffuse to tens of nanometers or more, making it impossible to distinguish individual molecules. Furthermore, tips with a radius of curvature ≥10 nm are difficult to precisely generate mechanical or electric field interactions with individual molecules, and are prone to interfering with multiple single molecules simultaneously.

[0040] The nanocavity structure is a planar metal nanocavity set on the sample stage surface. It is composed of Au or Ag nanoparticle dimers with a diameter of 50~200 nm and a dimer gap of 1 nm~10 nm, forming a nano-gap light field trap. It works in synergy with the STM tip to compress the light field to a single-molecule scale of less than 1 nm, achieving ultra-high localization enhancement of the light field.

[0041] In another feasible embodiment, the single-molecule Raman signal optical field modulation enhancement system further includes an optical field excitation module, which, after step S03 (controlling the piezoelectric control component to move the target single molecule to the current optical field region), further includes: Step S031: Determine the initial light field parameters based on the preset characteristic parameters of the target single molecule; In one feasible embodiment, the initial working state of the light field is set according to the preset characteristic parameters of the target single molecule.

[0042] The initial optical field parameters refer to the optical field state parameters set before the start of detection. These mainly include the excitation wavelength needing to match the peak value of the molecule's excitation energy level, the polarization state needing to match the direction of the molecule's transition dipole moment, the spatial phase distribution needing to ensure that the focused spot is aligned with the center of the nano gap, and the time-gated width needing to match the pulse characteristics of the Raman signal.

[0043] Step S032: Control the optical field excitation module to generate excitation light according to the initial optical field parameters and apply it to the sample to be tested.

[0044] The optical field excitation module includes a laser source, a beam collimation component, and a beam expander component, which are used to generate stable Raman excitation light. The laser source outputs laser light according to the preset wavelength, power, pulse width, and repetition frequency. After collimation and beam expansion, it forms an excitation beam that conforms to the initial optical field parameters. The excitation beam is further modulated by the optical field modulation module and then irradiates the sample surface to excite the target single molecule to generate a Raman scattering signal.

[0045] Before the formal excitation and detection begins, this embodiment performs personalized and differentiated initialization settings of the light field parameters based on the individual characteristics of the target single molecule. This allows key parameters such as excitation wavelength, polarization state, and focusing position to be adapted to the optimal excitation conditions of different molecules. This avoids the problem of poor initial matching caused by using uniform static preset values, which requires long-term dynamic adjustments to enter a stable detection state. As a result, the warm-up time for the system to enter efficient detection is shortened, and the overall detection efficiency and initial signal quality are improved.

[0046] This embodiment utilizes the nanoscale gap between the scanning tunneling microscope tip and the nanocavity structure to form the current light field region, solving the problems of insufficient local precision of the light field and the inability to compress the light field to the single-molecule scale in existing technologies. The synergistic design of the nanoscale gap and the tip curvature radius generates an extremely strong local electromagnetic field at the tip, concentrating the incident laser energy into a sub-nanometer hot spot. This ensures precise spatial matching between the excitation light field and the single molecule, avoiding energy waste and interference from neighboring molecules due to an excessively large hot spot region. Simultaneously, by controlling the scanning tunneling microscope tip to scan the surface of the sample to be tested, the target single molecule is actively moved to the current light field region. This overcomes the shortcomings of existing technologies where single molecules are randomly distributed and cannot be controlled to be guided to the light field hot spot. It realizes the process of moving molecules from passively waiting for them to enter the hot spot to actively capturing and moving them to the hot spot. It can accurately identify and move single molecules without interfering with surrounding molecules, significantly improving the spatial matching accuracy and detection stability between the light field and single molecules.

[0047] Step S20: Obtain the current Raman scattering signal of the target single molecule in the current light field region acquired by the Raman signal acquisition module; In one feasible embodiment, a sample to be tested is provided, and the intensity data of the Raman signal of the target single molecule under the current light field excitation is acquired in real time as a direct indicator of the light field modulation effect and molecular state. The current Raman scattering signal includes Raman characteristic peak intensity, signal-to-noise ratio, and peak position information. The acquisition process is synchronously triggered by a synchronization control module with a triggering accuracy of no less than 1 ns, ensuring that the signal acquisition is strictly aligned with the light field excitation and molecule capture time.

[0048] A single-molecule capture module is a functional unit used to capture, locate, and confine a single molecule.

[0049] A Raman signal acquisition module is a functional unit used to collect and detect Raman scattering signals.

[0050] The sample to be tested can be a biological sample or a polymer sample. The sample is dispersed on a transparent substrate (such as a quartz substrate) to prepare a monomolecular dispersion sample, ensuring that the density of monomolecules in the sample is moderate and avoiding molecular aggregation.

[0051] A target single molecule refers to a single molecule in the sample that needs to be studied or detected (such as a single protein, DNA, organic dye molecule, etc.).

[0052] The current optical field region refers to the spatial electromagnetic field range generated by the optical field modulation module that acts on the target single molecule. The current optical field region is usually the focal point of the excitation light or the near-field enhancement region, and its intensity distribution, polarization direction, phase and other parameters affect the Raman excitation efficiency and trapping force of the single molecule.

[0053] In another feasible embodiment, the Raman signal acquisition module includes: a near-field acquisition probe and a far-field acquisition component. Step S20, which acquires the current Raman scattering signal of the target single molecule in the current optical field region acquired by the Raman signal acquisition module, includes: Step S210: Acquire the first Raman scattering signal of the near-field region of the target single molecule collected by the near-field acquisition probe; In a feasible embodiment, the first Raman scattering signal mainly originates from the local electromagnetic field enhancement region at the tip of the needle, reflecting the vibrational information of the target single molecule itself. It has high spatial resolution and signal enhancement factor, but is easily affected by the state of the needle tip, molecular position shift, etc., resulting in large fluctuations in signal intensity.

[0054] The near-field collection probe is a precious metal-coated fiber probe, coaxially set with the STM tip, used to collect Raman scattering signals in the near-field region, with a collection efficiency of not less than 80%.

[0055] Step S220: Acquire the second Raman scattering signal of the far-field region of the target single molecule acquired by the far-field acquisition component; In one feasible embodiment, the second Raman scattering signal originates from scattered light over a larger spatial range, including background noise generated by the substrate, other molecules, impurities, etc., and the Raman signal in the non-enhanced region. The intensity is relatively stable but the spatial resolution is low, and it is mainly used to characterize the environmental background.

[0056] The far-field collection component includes a parabolic mirror and a focusing lens group. The parabolic mirror is used to reflect the Raman scattering signal from the far-field region to the focusing lens group, which focuses the scattered signal onto the spectral filtering component to achieve efficient collection of the far-field signal.

[0057] Step S230: Determine the current Raman scattering signal based on the first Raman scattering signal and the second Raman scattering signal.

[0058] In one feasible embodiment, the two Raman scattering signals from the near-field and far-field regions are comprehensively analyzed and processed to output an optimized current Raman scattering signal. The processing may include background subtraction, signal correction, noise suppression, and weighted fusion. The current Raman scattering signal obtained after fusion processing serves as the input for subsequent matching judgment steps. It retains the advantages of high resolution and high enhancement factor from near-field acquisition while subtracting environmental interference through background reference from the far-field signal, resulting in higher signal-to-noise ratio and accuracy.

[0059] Optionally, the Raman signal acquisition module also includes a spectral filtering component and a signal detection component. The spectral filtering component includes a long-pass filter and a narrow-band filter. The long-pass filter is used to filter the excitation light, and the narrow-band filter is used to filter stray light to ensure the purity of the Raman signal. The signal detection component includes a scientific-grade CCD camera and a photon counter. The scientific-grade CCD camera has a pixel size of no more than 10 μm and a quantum efficiency of no less than 90%. The photon counter has a response time of no more than 1 ns and is used to convert the collected Raman scattering signal into an electrical signal to achieve efficient signal detection.

[0060] This embodiment employs a dual-channel collaborative acquisition architecture for both near-field and far-field signals, coupled with high-precision optical and detection components, significantly improving the purity, efficiency, and reliability of single-molecule Raman signal acquisition. The near-field acquisition probe utilizes a noble metal-coated fiber optic probe, coaxially positioned with the STM tip, to accurately acquire the local Raman signal in the tip-enhanced region. Furthermore, its coaxial alignment with the scanning tunneling microscope facilitates real-time correlation with Raman spectral information. The far-field acquisition component combines a parabolic mirror and a focusing lens group, efficiently collecting a wide range of background scattered light, thus enhancing the overall performance and robustness of the single-molecule Raman detection system.

[0061] Step S30: Determine the matching status between the current light field region and the target single molecule based on the current Raman scattering signal and the current capture parameters; In a feasible embodiment, the current capture parameters can accurately reflect the spatial position state of the target single molecule, and the current Raman scattering signal can reflect the coupling efficiency between the excitation light field and the vibrational mode of the target single molecule. By fusing and judging the information from two different dimensions (molecular spatial position accuracy and light field-molecule coupling efficiency), the matching degree between the current light field region and the target single molecule can be accurately identified, and the specific types of mismatch can be accurately distinguished. This provides a scientific and accurate basis for subsequent differentiated control, avoiding the inefficiency caused by blind adjustment and repeated trial and error in traditional technologies.

[0062] Step S40: Determine the working parameters to be adjusted based on the matching between the current light field region and the target single molecule, and then adjust the working parameters.

[0063] In one feasible embodiment, different mismatch types require different control methods. Molecular position deviation requires adjustment of capture parameters for repositioning; optical field parameter mismatch requires adjustment of optical field parameters to optimize excitation conditions. The corresponding adjustment scheme is precisely selected based on the matching status, the parameters to be adjusted are determined, the adjustment is performed, the signal is reacquired, and the matching status is reassessed until a match is achieved.

[0064] Operating parameters refer to the set of adjustable parameters in the system. These can be adjustable parameters in the single-molecule capture module or adjustable light field parameters in the current light field region.

[0065] For example, refer to Figure 2 The single-molecule Raman signal light field modulation enhancement method provided in this embodiment can effectively improve the intensity of the single-molecule spectral characteristic peak signal, and the enhanced Raman spectrum has smaller fluctuations and stronger signals.

[0066] In this embodiment, the current capture parameters of the target single molecule in the sample under test within the current light field region are first acquired by the single-molecule capture module; the current Raman scattering signal of the target single molecule within the current light field region is acquired by the Raman signal acquisition module. This allows for the perception of the real-time state of the target single molecule from two dimensions: light field-molecule coupling and molecular spatial positioning accuracy, providing a complete data foundation for subsequent accurate judgment. Then, based on the current Raman scattering signal and the current capture parameters, the matching status between the current light field region and the target single molecule is determined; based on the matching status, the working parameters to be adjusted are determined and adjusted. By comprehensively analyzing the two signals, the modules and corresponding parameters requiring adjustment are accurately determined, overcoming the limitation of existing technologies that use a single control method to simultaneously address multiple light field mismatches in the Raman detection process of single molecules. This ensures that the adjusted current light field region continuously matches the real-time state of the target single molecule, significantly improving the accuracy of single-molecule Raman signal detection. Therefore, this embodiment achieves accurate detection of single-molecule Raman signals through a closed-loop control process that enhances the light field modulation signal.

[0067] Based on the first embodiment of this application, in the second embodiment of this application, the content that is the same as or similar to that in the first embodiment described above can be referred to the above description and will not be repeated hereafter. Based on this, step S40, which determines the working parameters to be adjusted according to the matching situation between the current light field region and the target single molecule, includes: Step S410: If the current capture parameter is less than the preset capture parameter threshold, determine the working parameter to be adjusted as the current capture parameter; Step S420: If the current Raman scattering signal is less than the preset Raman signal threshold, determine the working parameter to be adjusted as the current optical field parameter. Step S430: If the current capture parameter is less than the capture parameter threshold and the current Raman scattering signal is less than the Raman signal threshold, determine the working parameters to be adjusted as the current capture parameter and the current optical field parameter.

[0068] In one feasible embodiment, the operating parameters that need to be adjusted are accurately determined based on the comparison results between the current capture parameters and the current Raman scattering signal and their respective preset thresholds. Different adjustment objects are selected for different mismatch types to avoid blind adjustment.

[0069] The preset capture parameter threshold is a pre-set limit used by the system to determine whether the current capture parameter matches the current state of the target single molecule. If the current capture parameter is less than the capture parameter threshold, it indicates that the target single molecule has deviated from the optimal excitation position in the current light field region.

[0070] The preset Raman signal threshold is a pre-set limit set by the system to determine whether the current Raman scattering signal generated by the target single molecule in the current optical field region matches the current state of the target single molecule. If the current Raman scattering signal is less than the Raman signal threshold, it indicates that the optical field parameters in the current optical field region are no longer in the optimal excitation state.

[0071] In another feasible implementation, the operating parameters include current capture parameters, which include the tunneling current signal, the current spacing of the nano-gap, and the current position of the scanning tunneling microscope tip. The capture parameter threshold includes a current signal threshold. Step S40, adjusting the operating parameters, includes: Step A10: Determine the adjustment value of the current spacing based on the intensity change of the current Raman scattering signal; The tunneling current signal refers to the current signal generated between the STM tip and the sample due to the quantum tunneling effect. It has sub-nanometer exponential sensitivity to the tip-sample distance. The current changes by about an order of magnitude for every 0.1 nm increase in distance, so it can be used as a real-time probe of molecular spatial position.

[0072] In one feasible embodiment, when the detected tunneling current signal is less than a preset current signal threshold, it indicates that the target single molecule has deviated from the optimal position of the light field hotspot, and the localized state of the light field between the tip and the nanocavity does not meet the enhancement requirements. At this time, the system takes the real-time Raman scattering signal intensity change as the optimization target, and determines the target spacing between the tip and the nanocavity that can achieve the best localization effect of the light field and the strongest Raman signal through signal intensity feedback iteration. Then, it drives the piezoelectric control component to precisely adjust the height and displacement of the scanning tunneling microscope tip with sub-nanometer precision, adjusts the actual spacing of the nano gap to the target spacing, so that the single molecule returns to the core region of localized light field enhancement, and restores the high local field strength and stable Raman signal output.

[0073] Step A20: Perform a region search centered on the current position of the scanning tunneling microscope tip to determine the current position offset of the scanning tunneling microscope tip, and determine the position compensation value based on the current position offset; In one feasible embodiment, in order to compensate for the positional shift caused by factors such as changes in ambient temperature, mechanical vibration, and thermal expansion and contraction of the sample substrate during the detection process, based on determining the current position of the scanning tunneling microscope tip, a preset area search is performed within a small range centered on this position. By collecting tunneling current signals and Raman scattering signals point by point and comparing intensity changes, the actual position of the single molecule is accurately located. Then, the piezoelectric control component drives the scanning tunneling microscope tip and the nanocavity structure to perform sub-nanometer displacement correction, automatically eliminating the positional deviation caused by environmental drift, so that the target single molecule is always stably located in the core hot spot region of localized light field enhancement, ensuring continuous and accurate matching between the light field and the molecular position throughout the detection process.

[0074] Step A30: Control the single-molecule capture module to adjust according to the adjustment value and position compensation value, so that the adjusted tunnel current signal is greater than or equal to the current signal threshold.

[0075] In one feasible embodiment, by optimizing the spacing based on an adjustment value determined according to changes in Raman signal intensity, the tip can be precisely locked at the optimal height for nano-gap plasmon resonance, where the Raman signal is strongest. Furthermore, by moving the tip according to a position compensation value determined through region search, positional shifts caused by environmental temperature drift, mechanical vibration, etc., can be effectively compensated for, ensuring that the molecule remains within the core region of near-field enhancement.

[0076] This embodiment first determines the adjustment value of the nanogap based on the tunneling current signal and Raman scattering intensity feedback. Then, it uses a piezoelectric control component to adjust the nanogap, quickly resetting the target single molecule to the core enhancement region of the light field. Next, it performs a small-range search centered on the current position of the needle tip to accurately compensate for positional shifts caused by environmental temperature drift and vibration. Throughout the process, the single molecule is stably constrained at the center of the light field hotspot in the target light field region, significantly improving the local stability and modulation efficiency of the light field, ensuring continuous high-intensity output of the Raman signal, and greatly improving the repeatability, stability, and accuracy of the detection.

[0077] In another feasible implementation, the system further includes an optical field modulation module, wherein the current optical field parameters include at least one of spatial phase, spatial amplitude, polarization state, and time gating, and the operating parameters include the current optical field parameters, with reference to... Figure 3 Step S40, adjusting the operating parameters, includes: Step B10: When the tunnel current signal is greater than or equal to the current signal threshold, control the optical field modulation module to adjust the polarization state of the excitation light to match the transition dipole moment direction of the target single molecule. In one feasible embodiment, polarization dynamic matching is performed when the tunneling current signal is normal, i.e., the single molecule position is correct. This solves the problem in the prior art that it cannot actively track and adjust the polarization state when the direction of molecular vibration changes. Through polarization space frequency sweep and polar coordinate correlation analysis, the optimal coupling angle between the excitation photoelectric vector and the molecular transition dipole moment is accurately identified. Real-time dynamic adjustment of the polarization vector is achieved through periodic small perturbations, effectively eliminating the signal quenching phenomenon caused by single-molecule rotational dynamics and ensuring that the excitation energy is converted into molecular vibrational energy to the maximum extent.

[0078] Step B20: When the signal-to-noise ratio of the current Raman scattering signal decreases, control the optical field modulation module to adjust the spatial phase and spatial amplitude of the excitation light to suppress sidelobes; In a feasible embodiment, a decrease in signal-to-noise ratio (SNR) signifies a weakening of the signal relative to noise, typically due to insufficient spatial concentration of the excitation light field, resulting in additional scattering or fluorescence background, while simultaneously reducing the excitation efficiency of the target molecule. This is attributed to insufficient localization of the light field. Adjusting the spatial phase and amplitude of the excitation light, and suppressing the sidelobes of the DMD (Digital Micromirror Device) using SLM (Spatial Light Modulator) wavefront shaping techniques (such as using a spatial light modulator or deformable mirror), can highly concentrate the light field energy at the location of the target single molecule, enhancing the local field enhancement effect and improving signal purity and SNR.

[0079] Step B30: When the background noise of the current Raman scattering signal increases, control the optical field modulation module to adjust the acquisition time window to suppress background interference.

[0080] In one feasible embodiment, increased background noise (rather than a weakening signal) indicates that the acquired optical signal contains a large amount of non-target scattering (such as fluorescence, elastic scattering, Rayleigh scattering, etc.). This is usually because the acquisition time window of the time-gated system (including the delay time and window width) does not match the temporal characteristics of the target Raman signal: opening the window too early or too late will include unnecessary background light in the acquisition, while the target signal is compressed. Adjusting the time-gating parameters (e.g., changing the gating delay time, shortening or lengthening the gate width) so that the acquisition window is precisely aligned with the generation time of the target Raman signal (usually determined by the molecular vibrational lifetime) can effectively suppress background interference and improve the detection signal-to-noise ratio.

[0081] This embodiment constructs a closed-loop feedback control system based on multi-dimensional feature diagnosis. It avoids blindly adjusting a single parameter. Instead, it accurately distinguishes three attenuation types—polarization mismatch, insufficient optical field localization, and time-gated mismatch—by jointly analyzing the tunnel current signal, signal-to-noise ratio, and background noise level. It then performs polarization dynamic matching, wavefront reconstruction, and time-gated adjustment operations respectively, ensuring the rationality of the adjustment actions, avoiding unnecessary coupling interference between parameters, and quickly converging to the optimal working state, significantly improving the signal-to-noise ratio and purity of the signal.

[0082] For example, refer to Figure 4The optical field excitation module generates stable Raman excitation light, providing the light source for subsequent detection. The optical field modulation module performs multi-dimensional coordinated modulation of the phase, amplitude, polarization, and temporal characteristics of the excitation light to generate a customized optical field matching the vibrational mode of the target single molecule. The single-molecule capture module captures and confines the target single molecule to the current optical field region, and simultaneously constructs a near-field local enhancement structure through the synergistic effect of the scanning tunneling microscope tip and the nanocavity structure, compressing the optical field to the single-molecule scale. During these steps, the synchronization control module sends nanosecond-precision synchronization trigger signals to the optical field modulation module, the single-molecule capture module, and the Raman signal collection module to ensure the timing linkage of each module. The Raman signal collection module collects the first Raman scattering signal in the near-field region and the second Raman scattering signal in the far-field region through the near-field collection probe and the far-field collection component, respectively, achieving dual-channel coordinated collection. The data processing module performs noise reduction, spectral analysis, and molecular recognition on the detected Raman electrical signals, ultimately outputting the identification result and Raman spectrum of the target single molecule. This forms a complete closed loop for single-molecule Raman signal optical field modulation enhancement detection.

[0083] This application also provides a single-molecule Raman signal optical field modulation and enhancement system, referring to... Figure 5 The single-molecule Raman signal optical field modulation enhancement system includes: Single molecule capture module 10; Raman signal acquisition module 20; The control module 30 is communicatively connected to the single-molecule capture module 10 and the Raman signal acquisition module 20, respectively. It is used to acquire the current capture parameters of the target single molecule in the test sample in the current light field region acquired by the single-molecule capture module; acquire the current Raman scattering signal of the target single molecule in the current light field region acquired by the Raman signal acquisition module; determine the matching status between the current light field region and the target single molecule based on the current Raman scattering signal and the current capture parameters; determine the working parameters to be adjusted based on the matching status between the current light field region and the target single molecule, and adjust the working parameters.

[0084] The control module 30 also includes a synchronous trigger controller, a data acquisition card, and a control computer. The synchronous trigger controller uses a high-frequency synchronous trigger with a trigger frequency adjustable in the range of 1~100 MHz and a trigger accuracy of not less than 1 ns. It is used to send synchronous trigger signals to the light field modulation module, the single molecule capture and local enhancement module, and the Raman signal collection module. The data acquisition card has a sampling frequency of not less than 1 GHz and a sampling accuracy of not less than 16 bits. It is used to acquire the electrical signals output by the signal detection component and transmit them to the control computer. The control computer has built-in control software to receive the signals transmitted by the data acquisition card and send control commands to each module to adjust the light field parameters, tip position, time gating parameters, etc., so as to realize the automated control and synchronous linkage of the entire system.

[0085] In a feasible embodiment, the single-molecule Raman signal light field modulation enhancement system further includes a light field modulation module 40, used for multi-dimensional synergistic modulation of the phase, polarization, and temporal characteristics of the excitation light to generate a customized light field matching the single-molecule vibrational mode. This module includes a spatial light modulator, a digital micromirror device, a polarization modulation component, and a time-gated component. The spatial light modulator is a reflective liquid crystal spatial light modulator with a pixel resolution of at least 1024×768, a phase modulation range of 0~2π, and a response time of no more than 10 μs. It is used to phase-control the excitation light, achieve spatial reconstruction of the light field, and precisely focus the light field to the single-molecule position, forming a localized light field hotspot. The digital micromirror device has a pixel resolution of at least 1920×1080, a micromirror flip angle of ±12°, and a response time of no more than 1 μs. It is used to modulate the amplitude of the excitation light, suppress sidelobes, and improve the localization of the light field. The polarization modulation component includes an electrically controlled polarization controller and a waveplate, enabling rapid switching between various polarization states such as linear polarization, circular polarization, and radial polarization (switching speed not exceeding 1 μs). The time-gated component (ms) is used to control the polarization direction of the excitation light, match the vibration direction of a single molecule, and enhance the Raman signal of a specific vibrational mode. The time-gated component includes a time-gated detector and a delay generator. The time-gated width can be adjusted in the range of 10 ps to 1 ns, and the delay time can be precisely controlled (with an accuracy of not less than 1 ps). It is used to collect only the pulse period with the strongest Raman signal, suppress background fluorescence and stray light interference, and improve the signal-to-noise ratio.

[0086] In a feasible embodiment, the single-molecule Raman signal light field modulation enhancement system further includes a data processing module 50. The data processing module receives the Raman electrical signal transmitted by the control computer. First, it uses a signal denoising unit to suppress background noise and eliminate signal fluctuations using a machine learning algorithm. Then, it uses a spectral analysis unit to perform peak identification, intensity calculation, and peak position fitting on the denoised Raman spectrum to extract characteristic parameters such as the vibrational mode and scattering cross section of the single molecule. Finally, it uses a molecule recognition unit to match the extracted characteristic parameters with a preset single-molecule Raman spectrum database to achieve accurate identification of the target single molecule and output the identification result and Raman spectrum.

[0087] In a feasible embodiment, the single-molecule Raman signal optical field modulation enhancement system further includes an optical field excitation module 60. The optical field excitation module includes a laser source, a beam collimation component, and a beam expander component, used to generate stable excitation light. The laser source is a femtosecond pulsed laser source with an output wavelength adjustable in the range of 532 nm to 1064 nm, a pulse width of 10 to 100 fs, a repetition frequency of 1 to 100 MHz, and an adjustable output power (0 to 100 mW), ensuring the monochromaticity, coherence, and stability of the excitation light, while reducing background fluorescence interference through pulse excitation. The beam collimation component includes a collimating lens and a polarizer, used to collimate the laser output from the laser source into a parallel beam, while adjusting the initial polarization direction of the excitation light. The beam expander component includes a beam expander lens group, used to expand the collimated parallel beam to a preset size, adapting to the control range of the subsequent optical field modulation module.

[0088] After single-molecule detection is completed, the control module sequentially shuts down the light field excitation module, light field modulation module, single-molecule capture and local enhancement module, and Raman signal collection module, stopping signal acquisition and data processing; the sample stage is removed, the detection area is cleaned; and the power to the entire device is turned off, completing the detection process.

[0089] It should be noted that the above examples are only for understanding this application and do not constitute a limitation on the single-molecule Raman signal light field modulation enhancement method of this application. Any simple transformations based on this technical concept are within the protection scope of this application.

[0090] This application provides a single-molecule Raman signal light field modulation and enhancement device, which includes: at least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores instructions executable by the at least one processor, and the instructions are executed by the at least one processor to enable the at least one processor to perform the single-molecule Raman signal light field modulation and enhancement method in Embodiment 1 above.

[0091] The following is for reference. Figure 6 This document illustrates a schematic diagram of a single-molecule Raman signal light field modulation and enhancement device suitable for implementing embodiments of this application. The single-molecule Raman signal light field modulation and enhancement device in the embodiments of this application may include, but is not limited to, mobile terminals such as mobile phones, laptops, digital broadcast receivers, PDAs (Personal Digital Assistants), PADs (Portable Application Description), PMPs (Portable Media Players), and in-vehicle terminals (e.g., in-vehicle navigation terminals), as well as fixed terminals such as digital TVs and desktop computers. Figure 6The single-molecule Raman signal light field modulation and enhancement device shown is merely an example and should not impose any limitation on the functionality and scope of use of the embodiments of this application.

[0092] like Figure 6 As shown, the single-molecule Raman signal light field modulation and enhancement device may include a processing device 1001 (e.g., a central processing unit, a graphics processing unit, etc.), which can perform various appropriate actions and processes according to a program stored in a read-only memory 1002 or a program loaded from a storage device 1003 into a random access memory 1004. The random access memory 1004 also stores various programs and data required for the operation of the single-molecule Raman signal light field modulation and enhancement device. The processing device 1001, the read-only memory 1002, and the random access memory 1004 are interconnected via a bus 1005. An input / output interface 1006 is also connected to the bus. Typically, the following systems can be connected to the input / output interface 1006: input devices 1007 including, for example, touch screens, touchpads, keyboards, mice, image sensors, microphones, accelerometers, gyroscopes, etc.; output devices 1008 including, for example, liquid crystal displays (LCDs), speakers, vibrators, etc.; storage devices 1003 including, for example, magnetic tapes, hard disks, etc.; and communication devices 1009. Communication device 1009 allows the single-molecule Raman signal light field modulation and enhancement device to communicate wirelessly or wiredly with other devices to exchange data. Although the figure shows single-molecule Raman signal light field modulation and enhancement devices with various systems, it should be understood that implementation or possession of all the systems shown is not required. More or fewer systems may be implemented alternatively.

[0093] Specifically, according to the embodiments disclosed in this application, the processes described above with reference to the flowcharts can be implemented as computer software programs. For example, embodiments disclosed in this application include a computer program product comprising a computer program carried on a computer-readable medium, the computer program containing program code for performing the methods shown in the flowcharts. In such embodiments, the computer program can be downloaded and installed from a network via a communication device, or installed from storage device 1003, or installed from read-only memory 1002. When the computer program is executed by processing device 1001, it performs the functions defined in the methods of the embodiments disclosed in this application.

[0094] The single-molecule Raman signal light field modulation and enhancement device provided in this application employs the single-molecule Raman signal light field modulation and enhancement method described in the above embodiments. This solves the technical problem that existing light field modulation techniques suffer from low modulation efficiency for single-molecule Raman signals, leading to inaccurate detection of single-molecule Raman signals. Compared with the prior art, the beneficial effects of the single-molecule Raman signal light field modulation and enhancement device provided in this application are the same as those of the single-molecule Raman signal light field modulation and enhancement method provided in the above embodiments. Furthermore, other technical features of this single-molecule Raman signal light field modulation and enhancement device are the same as those disclosed in the previous embodiment method, and will not be repeated here.

[0095] It should be understood that the various parts disclosed in this application can be implemented using hardware, software, firmware, or a combination thereof. In the description of the above embodiments, specific features, structures, materials, or characteristics can be combined in any suitable manner in one or more embodiments or examples.

[0096] The above are merely specific embodiments of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

[0097] This application provides a computer-readable storage medium having computer-readable program instructions (i.e., a computer program) stored thereon, the computer-readable program instructions being used to execute the single-molecule Raman signal light field modulation enhancement method in the above embodiments.

[0098] The computer-readable storage medium provided in this application may be, for example, a USB flash drive, but is not limited to, electrical, magnetic, optical, electromagnetic, infrared, or semiconductor systems or devices, or any combination thereof. More specific examples of computer-readable storage media may include, but are not limited to: electrical connections having one or more wires, portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fiber, portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination thereof. In this embodiment, the computer-readable storage medium may be any tangible medium containing or storing a program that can be used by or in conjunction with an instruction execution system or device. The program code contained on the computer-readable storage medium may be transmitted using any suitable medium, including but not limited to: wires, optical cables, RF (Radio Frequency), etc., or any suitable combination thereof.

[0099] The aforementioned computer-readable storage medium may be included in the single-molecule Raman signal light field modulation and enhancement device; or it may exist independently and not assembled into the single-molecule Raman signal light field modulation and enhancement device.

[0100] The aforementioned computer-readable storage medium carries one or more programs. When these programs are executed by the single-molecule Raman signal light field modulation and enhancement device, the single-molecule Raman signal light field modulation and enhancement device: acquires the current capture parameters of the target single molecule in the current light field region of the sample to be tested, collected by the single-molecule capture module; acquires the current Raman scattering signal of the target single molecule in the current light field region, collected by the Raman signal acquisition module; determines the matching status between the current light field region and the target single molecule based on the current Raman scattering signal and the current capture parameters; and determines the operating parameters to be adjusted based on the matching status between the current light field region and the target single molecule, and adjusts the operating parameters.

[0101] Computer program code for performing the operations of this application can be written in one or more programming languages ​​or a combination thereof, including object-oriented programming languages ​​such as Java, Smalltalk, and C++, and conventional procedural programming languages ​​such as the "C" language or similar programming languages. The program code can be executed entirely on the user's computer, partially on the user's computer, as a standalone software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In cases involving remote computers, the remote computer can be connected to the user's computer via any type of network—including a Local Area Network (LAN) or a Wide Area Network (WAN)—or can be connected to an external computer (e.g., via the Internet using an Internet service provider).

[0102] The flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various embodiments of this application. In this regard, each block in a flowchart or block diagram may represent a module, segment, or portion of code containing one or more executable instructions for implementing a specified logical function. It should also be noted that in some alternative implementations, the functions indicated in the blocks may occur in a different order than those indicated in the drawings. For example, two consecutively indicated blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each block in the block diagrams and / or flowcharts, and combinations of blocks in the block diagrams and / or flowcharts, can be implemented using a dedicated hardware-based system that performs the specified function or operation, or using a combination of dedicated hardware and computer instructions.

[0103] The modules described in the embodiments of this application can be implemented in software or hardware. The names of the modules do not necessarily limit the functionality of the unit itself.

[0104] The readable storage medium provided in this application is a computer-readable storage medium that stores computer-readable program instructions (i.e., a computer program) for executing the above-described single-molecule Raman signal light field modulation enhancement method. This solves the technical problem that existing light field modulation techniques have low modulation efficiency for single-molecule Raman signals, leading to inaccurate detection of single-molecule Raman signals. Compared with the prior art, the beneficial effects of the computer-readable storage medium provided in this application are the same as those of the single-molecule Raman signal light field modulation enhancement method provided in the above embodiments, and will not be repeated here.

[0105] This application also provides a computer program product, including a computer program that, when executed by a processor, implements the steps of the single-molecule Raman signal light field modulation enhancement method as described above.

[0106] The computer program product provided in this application can solve the technical problem that the modulation efficiency of existing optical field modulation technology for single-molecule Raman signals is low, resulting in inaccurate detection of single-molecule Raman signals. Compared with the prior art, the beneficial effects of the computer program product provided in this application are the same as those of the single-molecule Raman signal optical field modulation enhancement method provided in the above embodiments, and will not be repeated here.

[0107] The above description is only a part of the embodiments of this application and does not limit the patent scope of this application. All equivalent structural transformations made under the technical concept of this application and using the contents of the specification and drawings of this application, or direct / indirect applications in other related technical fields, are included in the patent protection scope of this application.

Claims

1. A method for enhancing the optical field modulation of a single-molecule Raman signal, characterized in that, The method is applied to a single-molecule Raman signal optical field modulation and enhancement system, which includes a single-molecule capture module and a Raman signal acquisition module. The method includes: The current capture parameters of the target single molecule in the sample under test in the current light field region are obtained from the single molecule capture module. Acquire the current Raman scattering signal of the target single molecule in the current optical field region, acquired by the Raman signal acquisition module; Based on the current Raman scattering signal and the current capture parameters, determine the matching status between the current optical field region and the target single molecule; Based on the matching between the current light field region and the target single molecule, determine the working parameters to be adjusted, and then adjust the working parameters. The operating parameters include the current capture parameters, which include the tunneling current signal, the current spacing of the nano-gap, and the current position of the scanning tunneling microscope tip. The capture parameter threshold includes the current signal threshold, which is a limiting value used to determine whether the current capture parameters match the current state of the target single molecule. The step of adjusting the operating parameters includes: determining the adjustment value of the current spacing based on the intensity change of the current Raman scattering signal. A region search is performed centered on the current position of the scanning tunneling microscope tip to determine the current position offset of the scanning tunneling microscope tip, and a position compensation value is determined based on the current position offset. The single-molecule capture module is controlled to adjust according to the adjustment value and the position compensation value, so that the adjusted tunneling current signal is greater than or equal to the current signal threshold.

2. The method as described in claim 1, characterized in that, The single-molecule capture module includes: a scanning probe assembly, a nanocavity structure, and a piezoelectric control assembly. The scanning probe assembly includes a scanning tunneling microscope tip. Prior to the step of acquiring the current capture parameters of the target single molecule in the current light field region of the sample acquired by the single-molecule capture module, the module further includes: The initial capture parameters of the single-molecule capture module are determined based on the preset characteristic parameters of the target single molecule. Based on the initial capture parameters, a nano-gap is formed between the scanning tunneling microscope tip and the nanocavity structure to obtain the current light field region; The piezoelectric control component is controlled to move the target single molecule to the current light field region.

3. The method as described in claim 2, characterized in that, The single-molecule Raman signal optical field modulation and enhancement system further includes an optical field excitation module, which, after the step of controlling the piezoelectric control component to move the target single molecule to the current optical field region, further includes: The initial light field parameters are determined based on the preset characteristic parameters of the target single molecule; The optical field excitation module is controlled to generate excitation light according to the initial optical field parameters and apply it to the sample to be tested.

4. The method as described in claim 1, characterized in that, The step of determining the working parameters to be adjusted based on the matching between the current light field region and the target single molecule includes: If the current capture parameter is less than a preset capture parameter threshold, the working parameter to be adjusted is determined to be the current capture parameter. If the current Raman scattering signal is less than a preset Raman signal threshold, the operating parameter to be adjusted is determined to be the current optical field parameter. If the current capture parameter is less than the capture parameter threshold and the current Raman scattering signal is less than the Raman signal threshold, the operating parameters to be adjusted are determined to be the current capture parameter and the current optical field parameter.

5. The method as described in claim 4, characterized in that, The single-molecule Raman signal optical field modulation and enhancement system further includes an optical field modulation module. The current optical field parameters include at least one of spatial phase, spatial amplitude, polarization state, and time gating. The operating parameters include the current optical field parameters. The step of adjusting the operating parameters includes: When the tunnel current signal is greater than or equal to the current signal threshold, the optical field modulation module is controlled to adjust the polarization state of the excitation light to match the transition dipole moment direction of the target single molecule; When the signal-to-noise ratio of the current Raman scattering signal decreases, the optical field modulation module is controlled to adjust the spatial phase and spatial amplitude of the excitation light to suppress sidelobes; When the background noise of the current Raman scattering signal increases, the optical field modulation module is controlled to adjust the acquisition time window of the time gating to suppress background interference.

6. The method as described in claim 1, characterized in that, The Raman signal acquisition module includes a near-field acquisition probe and a far-field acquisition component. The step of acquiring the current Raman scattering signal of the target single molecule in the current optical field region acquired by the Raman signal acquisition module includes: Acquire the first Raman scattering signal of the near-field region of the target single molecule collected by the near-field acquisition probe; Acquire the second Raman scattering signal of the far-field region of the target single molecule acquired by the far-field acquisition component; The current Raman scattering signal is determined based on the first Raman scattering signal and the second Raman scattering signal.

7. A single-molecule Raman signal optical field modulation and enhancement system, characterized in that, The single-molecule Raman signal optical field modulation and enhancement system includes: Single-molecule capture module; Raman signal acquisition module; The control module is communicatively connected to the single-molecule capture module and the Raman signal acquisition module, respectively, and is used to execute the steps of the single-molecule Raman signal light field modulation enhancement method as described in any one of claims 1 to 6.

8. A storage medium, characterized in that, The storage medium is a computer-readable storage medium, and a computer program is stored on the storage medium. When the computer program is executed by a processor, it implements the steps of the single-molecule Raman signal light field modulation enhancement method as described in any one of claims 1 to 6.

9. A computer program product, characterized in that, The computer program product includes a computer program that, when executed by a processor, implements the steps of the single-molecule Raman signal light field modulation enhancement method as described in any one of claims 1 to 6.

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