Intelligent in-situ modification method and device for tip-enhanced Raman spectrum probe
By employing an intelligent TERS probe modification method that combines scanning imaging, oscillation control, and spectral detection, and utilizing the change in the apparent tunneling barrier height, rapid and intelligent optical activity assessment and modification of TERS probes are achieved. This solves the problems of long processing time and poor repeatability in existing technologies, and enables efficient and deterministic LSPR mode preparation of probes.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-30
- Publication Date
- 2026-04-10
AI Technical Summary
The existing TERS probe modification process is time-consuming, relies on manual operation, has poor repeatability, and cannot definitively obtain LSPR modes within a specific frequency range.
By combining scanning imaging, oscillation control, and spectral detection with machine learning, intelligent in-situ modification of the probe is achieved. Optical activity is determined by changes in the apparent tunneling barrier height, LSPR modes are automatically selected, and the scanning imaging process is decoupled.
It significantly shortens the probe modification time, improves repeatability and determinism, and enables rapid and intelligent optical activity judgment and modification of probes.
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Figure CN121830488A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The application belongs to the cross technical field of micro-nano optics and scanning probe microscopy, and particularly relates to an intelligent in-situ modification method and device for a tip-enhanced Raman spectroscopy probe. BACKGROUND
[0002] Tip-enhanced Raman spectroscopy (TERS) is a powerful ultra-high resolution spectroscopy technology, which combines the chemical specificity of Raman spectroscopy with the nanoscale spatial resolution of a scanning probe microscope (SPM), and is a key tool for realizing nanoscale “chemical imaging”. TERS technology can break through the diffraction limit of traditional optical microscopes and can simultaneously obtain surface topography and chemical structure information at a resolution of nanometers or even sub-nanometers.
[0003] The core of TERS technology is to use a metal probe (usually gold or silver) with “optical activity” to obtain a very small “hot spot” at the tip when it is irradiated by a laser. When the incident laser is focused on the tip of the metal probe, the collective oscillation of the free electrons on the metal surface is excited, forming localized surface plasmon resonance (LSPR), which greatly enhances the electromagnetic field in the tunnel junction formed by the probe tip and the substrate, thereby significantly enhancing the Raman signal. Therefore, the key to realizing TERS technology is how to obtain a metal probe with “optical activity”.
[0004] The existing probe modification process is that the experimental personnel convey the metal probe after chemical etching and vacuum annealing treatment to an ultra-high vacuum low-temperature environment, and perform the optical activity modification of the probe through repeated in-situ modification processes of the following cycles: down-sticking (or bias voltage pulse)-lifting the probe-scanning imaging-spectrum acquisition, and combining the observation of the peak position movement of the scanning tunneling spectroscopy (STS) or the intensity of the TERS spectrum to determine whether the probe has sufficient optical activity. The existing probe modification process has the following defects: first, the probe modification process involves multiple cycles of down-sticking (or bias voltage pulse)-lifting the probe-scanning imaging-spectrum acquisition, which is time-consuming and often lasts for several hours or even several days; second, the LSPR frequency, which is crucial for Raman enhancement, is completely random in the probe modification process, and it is impossible to obtain the LSPR mode in a specific frequency range with certainty; third, the human operation has strong contingency and poor repeatability, and is too dependent on the experience of the operator.
[0005] How to develop an intelligent, fast and decoupled TERS probe optical activity judgment and in-situ modification method, coordinate the automatic data transmission of the program in the whole process experiment, the decision instrument related operation, realize the intelligent TERS probe optical activity in-situ modification of high efficiency, at the same time, ensure that the TERS probe has LSPR mode in a certain frequency range, is the core technical problem to be solved in the application. SUMMARY
[0006] To solve the above technical problems, the application adopts the following technical scheme:
[0007] An intelligent in-situ modification method of a needle tip enhanced Raman spectrum probe, comprising:
[0008] Step 1, moving the probe to a flat area by scanning imaging: scanning several rows in a predetermined side length scanning frame by constant current mode, segmenting linear fitting of the probe height Z data in the scanning topography height map, and regarding the area with variance meeting the flatness requirement as a flat area, and moving the probe to the center of the flat area;
[0009] Step 2, gradually increasing the integral gain of the STM constant current control, controlling the mechanical oscillation of the probe into contact with the substrate, and repeatedly contacting the probe tip with the substrate in the oscillation process, realizing the modification of the atomic level topography of the probe tip, and controlling the mechanical oscillation of the probe to be in a critical state, and sensitively capturing the oscillation stop caused by the apparent barrier height drop of the optical activity;
[0010] Step 3, after the oscillation stops, performing secondary detection of the optical activity of the probe by the spectrum analyzer control interface: under the set needle tip enhanced Raman spectrum measurement condition, a sharp peak appears in the low frequency region, and the highest intensity of the sharp peak meets the preset signal-to-noise ratio requirement, to judge whether the probe has optical activity at this time; if the probe has optical activity, the intelligent in-situ modification method of the needle tip enhanced Raman spectrum probe is completed; if the probe has no optical activity, a flat area is found again to enter the next cycle;
[0011] Step 4, if the probe still has no optical activity after multiple cycles, continuously driving the probe several times at the position judged as the flat area, or applying a bias pulse to the probe to destroy its tip structure, until the monitored probe height in the constant current mode appears obvious change, after refreshing the state of the probe tip, entering a new cycle round, continuing to perform steps 1 to 3 to modify the probe, until the probe obtains optical activity.
[0012] An intelligent in-situ modification device of a needle tip enhanced Raman spectrum probe, comprising:
[0013] The flat area search module moves the probe to the flat area through scanning imaging: it scans several rows within a scanning frame of a predetermined side length using constant current mode, segments the probe height Z data in the scanning topography height map into linear fits, and considers the area whose variance meets the flatness requirements as the flat area, and moves the probe to the center of the flat area.
[0014] The oscillation control module gradually increases the integral gain of the STM constant current control, controlling the probe to enter mechanical oscillation in contact with the substrate. During the oscillation, the probe tip repeatedly contacts the substrate, achieving atomic-level morphology modification of the probe tip. The mechanical oscillation of the probe is controlled to be in a critical state, sensitively capturing the oscillation stop caused by the decrease in the tunneling apparent barrier height due to optical activity.
[0015] The optical activity assessment module performs a secondary detection of the probe's optical activity via the spectrometer control interface after the oscillation stops: under the set tip-enhanced Raman spectroscopy measurement conditions, if a peak feature appears in the low wavenumber region and the highest intensity of the peak meets the preset signal-to-noise ratio requirement, it determines whether the probe has optical activity; if the probe already has optical activity, the intelligent in-situ modification method of the tip-enhanced Raman spectroscopy probe is completed; if the probe has no optical activity, a flat region is searched again to enter the next cycle;
[0016] If the probe still lacks optical activity after multiple cycles, the probe is repeatedly driven into a flat area, or a bias pulse is applied to the probe to disrupt its tip structure, until a significant change in the probe height monitored in constant current mode is observed. After the probe tip state is refreshed, a new cycle begins, and the operations of the flat area search module, oscillation control module, and optical activity judgment module are executed sequentially to modify the probe until it gains optical activity.
[0017] The present invention has the following beneficial effects:
[0018] (1) This invention utilizes the change in the apparent barrier height (ABH) of tunneling as a real-time criterion for optical activity, thereby eliminating the dependence of the probe optical activity judgment process on scanning imaging and significantly shortening the time consumption of the probe modification process. Once an LSPR mode resonating with the incident laser is generated below the probe (i.e., it has optical activity), the ABH caused by the photocurrent generated by photon-assisted tunneling will drop sharply, which can be used as the basis for determining that the probe has acquired optical activity, thus reducing the dependence of the probe optical activity judgment process on scanning imaging.
[0019] (2) The application monitors the critical oscillation state of the STM constant current feedback instability to determine the decrease of ABH by developing a machine learning method with less manual marking. During the in-situ probe modification, on the one hand, by increasing the STM constant current control integral gain (I-gain) parameter, the probe instability enters a high-frequency oscillation state and repeatedly contacts the substrate, thereby realizing the modification of the atomic-level morphology of the probe tip; on the other hand, the machine learning method with less manual marking is used to determine the oscillation state of the probe in real time, and the integral gain (I-gain) of the constant current control is adjusted to keep the probe in a critical state between non-oscillation and sufficient oscillation, and the sensitivity to the change of ABH is maintained. Once the ABH decreases, the oscillation threshold will be raised above the current set I-gain value, and the oscillation state will stop immediately. Such operation can quickly capture the moment when the probe has optical activity, and can also avoid easily oscillating again to damage the atomic-level morphology of the probe tip and affect its optical activity.
[0020] (3) The application can automatically select the probe with a large ABH decrease under different wavelength laser excitation by selecting different incident laser wavelengths, and then selectively modify the optical activity probe with LSPR mode in the target frequency range, to realize the intelligent customization of the LSPR frequency of the optical activity probe. BRIEF DESCRIPTION OF DRAWINGS
[0021] Figure 1 The structure schematic diagram of the intelligent in-situ modification device for the needle tip enhanced Raman spectrum probe of the application;
[0022] Figure 2 The scheduling flowchart of the intelligent in-situ modification method for the needle tip enhanced Raman spectrum probe of the application;
[0023] Figure 3 The probe height (STM scanning tube Z direction displacement)-time trajectory curve diagram during the oscillation starting to the probe modification completion in a constant current mode;
[0024] Figure 4 The needle tip TERS spectrum data result diagram before and after the probe modification;
[0025] Figure 5 The STM induced luminescence spectrum data result. DETAILED DESCRIPTION
[0026] In order to make the purpose, technical scheme and advantages of the application more clear and understandable, the application will be further described in detail below in combination with the drawings and examples. It should be understood that the specific examples described herein are only used to explain the application and not to limit the application. In addition, the technical features involved in each embodiment of the application described below can be combined with each other as long as they do not conflict with each other.
[0027] The present application provides an in-situ modification method (hereinafter or in-situ modification method) and device of an intelligent needle tip enhanced spectroscopic active probe with customizable plasmonic resonance frequency. Figure 1 The device of the present application comprises the following seven parts, including two interfaces and five modules:
[0028] Scanning tunneling microscope (STM) control interface: used to send probe XYZ direction displacement data, constant current parameters, bias setting, scanning imaging and other instructions to the controller of the STM, and request probe XYZ direction displacement data, tunneling current data, scanning imaging data and other information from the controller of the STM.
[0029] Spectrometer control interface: provides an interface for calling spectrometer control software, triggering the spectrometer to perform spectrum acquisition, setting exposure time and saving position, obtaining spectrum data from the saved position, etc.
[0030] Flat area search module: scan several rows in a 50nm side length scanning frame in constant current mode, and regard the area where the segmented linear fitting variance of probe height Z in the scanning topography height map meets the flatness requirement as a flat area, and move the probe to the center of the flat area.
[0031] Oscillation control module: gradually increase the STM constant current control integral gain (I-gain) to make the probe enter mechanical oscillation in contact with the substrate (judged by the intermittent saturation of the tunneling current), and then classify the tunneling current and height trajectory of the probe through a machine learning classifier to divide the oscillation state of the probe into a critical oscillation state and a sufficient oscillation state. The machine learning classifier uses an automatic encoder to reduce the dimension of the data, and then uses a Gaussian mixture model (GMM) pre-trained and manually labeled clustering results for classification. When the probe is in the sufficient oscillation state, reduce the constant current control integral gain (I-gain); when the probe is not in the sufficient oscillation state (critical oscillation state), increase the constant current control integral gain (I-gain), so that probes in different states are in the critical oscillation state. The reduction of apparent barrier height (ABH) will lead to the increase of oscillation threshold; and the critical oscillation state is most sensitive to the change of ABH, i.e. the change of ABH is most likely to cause the stop of the oscillation state of the probe. Therefore, when the probe has optical activity, plasmonic assisted tunneling current will appear, causing a sudden decrease in ABH, and thus the oscillation of the probe will suddenly stop. In other words, once the oscillation of the probe stops, it is considered that the probe has optical activity at this time, and the constant current control integral gain (I-gain) is reduced and the probe height is raised to protect the needle tip. In the constant current mode, the probe oscillation starts after the probe is in the tunneling state, and the probe height (STM scanning tube Z direction displacement)-time trajectory curve in the process from the completion of the probe modification is as follows: Figure 3As shown, the horizontal axis represents time, and the vertical axis represents the probe's Z-axis displacement. Oscillation amplitude changes are recorded with an accuracy of 0.02 s, illustrating the entire process from the probe entering a controlled oscillation state until it acquires TERS activity, ends the oscillation, and is then lifted for protection. Using the oscillation control module, rapid changes in tip morphology and monitoring of probe optical activity can be achieved simultaneously without scanning imaging, improving the efficiency of preparing optically active probes.
[0032] Optical activity assessment module: Under the conditions of scanning tunneling microscope with scanning bias voltage set to -0.1V, tunneling current set to 1nA, laser wavelength / power set to 532nm / 600μW, and spectral integration time set to 10s (all conditions can be changed according to actual conditions), at low wavenumbers (<200cm²), the optical activity assessment module assesses the optical activity of the target material. -1 If a spike appears in the region, and the highest intensity of the spike meets a preset signal-to-noise ratio requirement as a threshold, it is used to determine whether the probe has optical activity. The threshold standard can be adjusted according to actual needs.
[0033] The probe-drilling refresh module: In areas deemed flat, the module operates the probe to drill several times under conditions of -1V bias, 2pA current, 0.1s drilling duration, and 1nm depth. Alternatively, a bias pulse of 6V for 50ms duration is applied to the probe to disrupt its tip structure (the drilling or bias pulse conditions can be adjusted). The module repeatedly performs the drilling or bias pulse operation until a significant change in the probe height monitored in constant current mode is observed. Since the probe-substrate spacing under the same tunneling current is related to the atomic-level morphology of the probe tip, the change in probe height in constant current mode directly reflects the change in the atomic-level structural characteristics of the probe tip, thus completing the refresh of the probe tip state.
[0034] Scheduling module: Performs in-situ probe modification process of flat area search, oscillation control and optical activity judgment within a specified time. If the probe fails to acquire optical activity after multiple consecutive attempts, it calls the refresh module to refresh the tip state and move the probe to a position farther away from the current position. The cycle ends after successfully preparing an optically active probe or after timeout (all calls in this invention are made through the scheduling module).
[0035] The following combination Figure 2 The specific implementation methods of the present invention are as follows:
[0036] Step 1: The coarsely processed metal probe is transferred to the observation chamber of the scanning tunneling microscope (STM) and inserted into the surface of the processed metal substrate.
[0037] The laser is turned on, and the incident laser wavelength is set to 532 nm, so that the laser spot covers the STM tunneling junction region. First, the flat area search module is called, which moves the probe to a flat area through scanning imaging: several rows are scanned in a 50 nm square scanning frame in constant current mode, the probe height Z data in the scanning topography height map is piecewise linearly fitted, and the area with a variance meeting the flatness requirement is regarded as a flat area, and the probe is moved to the center of the flat area (for different samples, additional criteria for judging the flatness of the sample surface can be added).
[0038] Step 2, as shown in the accompanying Figure 3 oscillation control module: gradually increase the STM constant current control integral gain (I-gain) to make the probe enter mechanical oscillation in contact with the substrate (judged by the intermittent saturation of tunneling current), and the probe tip repeatedly contacts the substrate during oscillation, achieving atomic-level modification of the probe tip morphology. The mechanical oscillation of the probe is controlled in a critical state, and the oscillation stop caused by the decrease of the apparent barrier height of the tunneling caused by the optical activity is sensitively captured. The oscillation control module classifies the oscillation state into critical oscillation and sufficient oscillation through a machine learning classifier. When the probe is in a sufficient oscillation state, the constant current control integral gain (I-gain) is reduced, and when the probe is in a critical oscillation state, the constant current control integral gain (I-gain) is increased, thereby controlling the oscillation in a critical state and intelligently adapting to various probes and various states of the probe. Since the probe is kept in a critical oscillation state, when the probe has optical activity, plasmonic-assisted tunneling current will occur, which is manifested as a sudden decrease in the apparent barrier height (ABH) of the tunneling and an increase in the oscillation threshold, and the probe oscillation immediately stops. At this time, the constant current control integral gain (I-gain) is reduced and the probe height is raised to protect the needle tip. Although the pre-trained machine learning classifier is used to control the oscillation state of the probe in this embodiment, other monitoring quantities or algorithms can also be used to control the oscillation state of the probe in other embodiments.
[0039] Step 3, after the oscillation stops, the optical activity judgment module is started, and the probe optical activity is detected again through the spectrometer control interface: under the conditions of bias voltage -0.1 V, current 1 nA, laser wavelength / power 532 nm / 600 μW, and spectrum integration time 10 s (each condition can be changed according to actual conditions), as shown in the accompanying Figure 4 , a sharp peak appears in the low wavenumber (<200 cm -1 ) region, and the highest intensity of the sharp peak meets the signal-to-noise ratio requirement as the threshold value. It is judged whether the probe has optical activity at this time, and the threshold value can be adjusted according to actual needs. Figure 4 shows the low wavenumber sharp peak (<200 cm -1The feature is generated from scratch, where the horizontal axis represents the Raman shift and the vertical axis represents the spectral intensity. This feature is used to ultimately verify whether the modified probe has optical activity, serving as a supplement and verification to the ABH method for detecting the probe's optical activity. Based on the detection results, the next step is performed: if the probe already has optical activity, the intelligent in-situ modification method for tip-enhanced Raman spectroscopy probes is complete, and the step stops; if the probe has no optical activity, a new flat region is searched for, and the next cycle begins.
[0040] Step 4: If the probe still has no optical activity after multiple cycles, call the burping refresh module to perform several consecutive burping operations on the probe at the location determined to be a flat area, with a bias voltage of -1V, a current of 2pA, a burping duration of 0.1s, and a depth of 1nm, or apply a bias voltage pulse of 6V and a duration of 50ms to the probe to destroy the tip structure (the parameters of burping or bias pulse can be adjusted).
[0041] The probe tip refresh module repeatedly performs the insertion or applies a bias pulse until a significant change in the monitored probe height in constant current mode is observed, thus completing the tip refresh. After the tip refresh, a new cycle begins, continuing steps 1 to 3 to modify the probe until an optically active probe is obtained.
[0042] Application Extension: To address different LSPR resonance peak position requirements, the incident laser wavelength in step 1 can be modified (e.g., modified to 633nm), and steps 1-4 can be repeated to customize optically active probes with different LSPR frequencies. To meet the LSPR resonance peak position requirements of different experiments, changing the incident laser wavelength and performing steps 1 to 4 above will ensure good coupling between the LSPR mode of the optically active probe and different excitation wavelengths, meaning the LSPR peak position of the optically active probe is near the incident laser wavelength, such as... Figure 5 As shown. In this way, the LSPR frequency of the needle tip can be customized by selecting a specific incident laser wavelength. Figure 5 The STM-induced emission spectroscopy data show the LSPR peak positions of the modified optically active probes excited by incident lasers at wavelengths of 532 nm and 633 nm, respectively. The laser wavelengths are marked with vertical lines. The corresponding STM-induced emission spectra show that the LSPR peaks are located near the incident laser wavelengths. The STM-induced emission spectra were obtained under conditions of -3.5 V and 1 nA. Figure 5 This indicates that the present invention can achieve intelligent customization of the LSPR frequency of optically active probes.
[0043] Example 1: A Ag (silver element) probe with a diameter of 0.3 mm is selected, cleaned by electrochemical corrosion and vacuum annealing, and then placed in a STM vacuum chamber with a temperature of 6 K. The above in-situ modification method is performed 400 times in succession on an Ag (100) single crystal under laser excitation of a 532 nm wavelength laser. Before each test, the sample is punctured and a bias voltage pulse is applied to the flat area to destroy the optical activity of the tip. Then, the above in-situ modification method is used to modify the optical activity of the probe, and the time for a single run is limited to within 10 minutes (i.e. 600 s). If the modification is not successful within 10 minutes, it is considered a failure. According to statistics, the number of times that the probe successfully obtains optical activity within 120 s using the method of the present application is 65.8%, the number of times that the probe successfully obtains optical activity within 300 s is 89.8%, and the total number of successful times within 600 s is 96.8%. The average time for a single probe to obtain optical activity is about 122 s.
[0044] Example 2: The 532 nm wavelength laser of Example 1 is replaced with a 633 nm wavelength laser, and similar 400 times of continuous probe modification tests are performed. According to statistics, the number of times that the probe successfully obtains optical activity within 120 s using the method of the present application is 55.2%, the number of times that the probe successfully obtains optical activity within 300 s is 87.5%, and the total number of successful times within 600 s is 98.2%. The average time for a single probe to obtain optical activity is about 150 s.
[0045] From the results of the running examples, it can be seen that the present method can efficiently modify the optical activity of the probe. The time for a single in-situ modification of the optical activity of the probe is reduced from several hours / days in the prior art to the order of minutes, and the process is stable (can be continuously run for more than 40 hours). In addition, since the oscillation control module can intelligently capture the tip state that is well coupled with the selected excitation light wavelength, i.e. the LSPR peak of the optical activity probe is near the incident laser wavelength, the success rate of the probe modification is greatly improved. Figure 5Therefore, the present application can achieve the customization of the probe plasmon resonance frequency range by using the excitation light wavelength. In addition, although the two embodiments are both on Ag probe and Ag substrate, similarly, for other needle tip systems with plasmonic enhancement effect, such as Au (gold element) probe, Al (aluminum element) probe, etc., as long as the element materials of the probe and the substrate are the same, the modification method of the present application is also applicable. Even for those probe systems without plasmonic enhancement effect, such as W (tungsten), Fe (iron) probe, etc., the modification method of the optical active probe described in the present application can also be used to modify the probe tip on the substrate with plasmonic activity (such as Au, Ag) to prepare the needle tip with optical activity.
[0046] Those skilled in the art will appreciate that embodiments of the present application can be readily used as a method, a system or a computer program product. Accordingly, the present application can take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present application can take the form of a computer program product on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROMs, optical storage devices, etc.) embodying computer-readable program code. Embodiments of the present application can be implemented in various computer languages.
[0047] The present application is described in reference to the flowchart and / or block diagrams of the method, apparatus (system) and computer program product according to the embodiments of the present application. It should be understood that each flow and / or block in the flowchart and / or block diagram, as well as a combination of flows and / or blocks in the flowchart and / or block diagram can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device produce the functions specified in the flowchart and / or block diagram block or blocks. Figure 1 one or more flows and / or blocks Figure 1 means for performing the function specified by the flow or flows and / or block or blocks.
[0048] These computer program instructions can also be stored in a computer-readable memory that can direct the computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer-readable memory produce a product including instruction means, which implements the functions specified in the flowchart and / or block diagram block or blocks. Figure 1 one or more flows and / or blocks Figure 1 one or more blocks or blocks.
[0049] These computer program instructions can also be loaded into a computer or other programmable data processing devices, so that a series of operational steps are performed on the computer or other programmable data processing devices, to generate a computer implemented process, so that the instructions executed on the computer or other programmable data processing devices provide the function of implementing the flow Figure 1 one or more flows and / or blocks Figure 1 one or more blocks or a plurality of blocks.
[0050] Although the preferred embodiments of the application have been described, those skilled in the art will be able to make additional modifications and variations to these embodiments without departing from the spirit and scope of the application. Accordingly, the appended claims are intended to encompass within their scope all such modifications and variations as fall within the scope of the application.
[0051] Obviously, various modifications and changes can be made to the present application by those skilled in the art without departing from the spirit and scope of the present application. Accordingly, the present application intends to include all such modifications and changes as fall within the scope of the claims and their equivalents.
[0052] The above description is merely illustrative of the application, and is not intended to limit the scope of the application. Any equivalent structure or equivalent processes that directly or indirectly serve the same function are also intended to be included in the scope of the application.
[0053] The contents not described in detail in the specification of the present application are the prior art known to those skilled in the art.
Claims
1. An intelligent in-situ modification method of a needle-tip-enhanced Raman spectroscopy probe, characterized in that, Comprise: Step 1, move the probe to a flat area by scanning imaging: scan several rows in a predetermined side length scanning frame by constant current mode, piecewise linear fitting of the probe height Z data in the scanning topographic height map, the area with variance meeting the flatness requirement is regarded as a flat area, and the probe is moved to the center of the flat area; Step 2, gradually increase the STM constant current control integral gain, control the probe to enter the mechanical oscillation in contact with the substrate, the probe tip repeatedly contacts the substrate during oscillation, and the atomic level morphology of the probe tip is modified, the mechanical oscillation of the probe is in a critical state, and the oscillation stop caused by the apparent barrier height reduction of the tunneling caused by the optical activity is sensitively captured; Step 3, after the oscillation stops, the secondary detection of the optical activity of the probe is carried out through the control interface of the spectrometer: under the set tip-enhanced Raman spectrum measurement conditions, a sharp peak appears in the low wave number region, and the highest intensity of the sharp peak meets the preset signal-to-noise ratio requirement, to judge whether the probe has optical activity at this time; If the probe has optical activity, the intelligent in-situ modification method of the tip-enhanced Raman spectrum probe is completed; If the probe has no optical activity, find a flat area and enter the next cycle; Step 4, if the probe still has no optical activity after several cycles, judge the position of the flat area and implement continuous several times of down-punching on the probe, or apply a bias pulse to the probe to destroy its tip structure, until the monitored probe height in the constant current mode appears obvious change, after the tip state of the probe is refreshed, enter a new cycle round, continue to execute steps 1 to 3, and modify the probe until the probe obtains optical activity. 2.The in-situ modification method of the intelligentized needle-tip-enhanced Raman spectroscopy probe according to claim 1, characterized in that, Before step 1, the probe is moved to a flat area, which includes: the coarsely processed metal probe is transmitted to the observation cavity of the scanning tunneling microscope, and the probe is inserted into the surface of the processed metal substrate; Turn on the laser, set the incident laser wavelength, and make the laser spot cover the STM tunnel junction area. 3.The method of claim 1, wherein, In step 1, for different samples, additional criteria for judging the flatness of the sample surface are added. 4.The method of claim 1, wherein, In step 2, the mechanical oscillation of the probe in contact with the substrate is judged by the intermittent measurement saturation of the tunneling current. 5.The method of claim 1, wherein, In step 2, the oscillation state is classified into critical oscillation and sufficient oscillation by a machine learning classifier, the integral gain of the constant current control is reduced when the probe is in the sufficient oscillation state, and the integral gain of the constant current control is increased when the probe is in the critical oscillation state, so as to maintain the oscillation in a critical state and intelligently adapt to various types of probes and various states of the probe tip. 6.The method of claim 1, wherein, Step 2 includes: when the probe has optical activity, plasmonic assisted tunneling current will appear, which is manifested as a sudden decrease in apparent barrier height, thereby causing the probe oscillation threshold to be raised above the current setting value, and the probe mechanical oscillation immediately stops; At this time, the integral gain of the constant current control is lowered and the probe height is raised to protect the probe tip. 7.The method of claim 1, wherein, In step 3, the working conditions of the tip-enhanced Raman spectrum are set or changed according to actual needs. 8.The method of claim 1, wherein, In step 4, the parameters of the down-punching are set or changed according to actual needs. 9.The method of claim 2, wherein, Also include: To meet different LSPR resonance peak position requirements, the incident laser wavelength is modified, and steps 1 to 4 are repeated to customize optically active probes of different frequencies.
10. An intelligent in-situ modification device for a needle-tip enhanced Raman spectroscopy probe, characterized in that, include: The flat area search module moves the probe to the flat area through scanning imaging: it scans several rows within a scanning frame of a predetermined side length using constant current mode, segments the probe height Z data in the scanning topography height map into linear fits, and considers the area whose variance meets the flatness requirements as the flat area, and moves the probe to the center of the flat area. The oscillation control module gradually increases the integral gain of the STM constant current control, controlling the probe to enter mechanical oscillation in contact with the substrate. During the oscillation, the probe tip repeatedly contacts the substrate, achieving atomic-level morphology modification of the probe tip. The mechanical oscillation of the probe is controlled to be in a critical state, sensitively capturing the oscillation stop caused by the decrease in the tunneling apparent barrier height due to optical activity. The optical activity assessment module performs a secondary detection of the probe's optical activity via the spectrometer control interface after the oscillation stops: under the set tip-enhanced Raman spectroscopy measurement conditions, if a peak feature appears in the low wavenumber region and the highest intensity of the peak meets the preset signal-to-noise ratio requirement, it determines whether the probe has optical activity; if the probe already has optical activity, the intelligent in-situ modification method of the tip-enhanced Raman spectroscopy probe is completed; if the probe has no optical activity, a flat region is searched again to enter the next cycle; If the probe still lacks optical activity after multiple cycles, the probe is repeatedly driven into a flat area, or a bias pulse is applied to the probe to disrupt its tip structure, until a significant change in the probe height monitored in constant current mode is observed. After the probe tip state is refreshed, a new cycle begins, and the operations of the flat area search module, oscillation control module, and optical activity judgment module are executed sequentially to modify the probe until it gains optical activity.