Confocal single photon detection system and method based on scanning analysis of galvanometer group

Abstract

The invention relates to the technical field of single-photon detection, in particular to a confocal single-photon detector based on scanning analysis of a galvanometer group and a detection method of the confocal single-photon detector. Comprising a detection box, a PC end data processing system, a confocal light path system, a confocal scanning control system, a PC end data processing system and an external acquisition card. The confocal single photon detector based on galvanometer scanning analysis is comprehensive teaching equipment integrating a confocal system, a lighting system, materials and a software algorithm, and the equipment can operate under the conditions of normal temperature and normal pressure and is suitable for most teaching experiment environments; student experiments widely relate to optical imaging experiments, galvanometer scanning regulation and control, signal acquisition, algorithm processing, equipment maintenance and the like, and exercise effects are achieved from all aspects.

Description

Technical Field

[0001] The present invention relates to the field of single-photon detection technology, and specifically to a confocal single-photon detector based on galvanometer group scanning analysis and a detection method thereof. Background Art

[0002] Currently, the integrated TCSPC systems widely used in the market are mostly scientific research instruments, primarily used in quantum physics fields such as quantum optics, fluorescence lifetime imaging (FLIM), single-molecule spectroscopy, quantum entanglement, and quantum source performance characterization. These devices are typically designed for high-end research laboratories and feature high precision, high confidentiality, and strict experimental environment requirements, making them suitable for challenging experiments such as parameter measurement and property characterization. However, this also results in their bulk, high price, and complex operation, making them unsuitable for everyday teaching.

[0003] In the field of teaching, the lack of low-cost, modular, highly stable single-photon detection equipment that is adaptable to diverse experimental content has become a key bottleneck restricting the deepening development of experimental teaching. Summary of the Invention

[0004] In response to the above problems, a confocal single-photon detector based on galvanometer scanning analysis and a detection method thereof are provided to meet the teaching and experimental needs of single photons.

[0005] To solve the problems in the prior art, the present invention provides a confocal single-photon detector based on galvanometer scanning analysis, which is characterized by comprising:

[0006] A detection box, the front panel of which has a communication interface;

[0007] A PC data processing system is connected to the detection box through the communication interface;

[0008] A confocal optical system is installed on the periphery of the detection box, and the confocal optical system includes an imaging optical path, an excitation optical path, and a collection optical path;

[0009] The imaging optical path includes a light source module, a sample platform, a microscope objective lens, a tube lens group, a spectroscope and a camera arranged in sequence along the optical path;

[0010] The excitation light path includes an optical fiber excitation group, a first reflector, a dichroic mirror, a galvanometer group, a field lens group, a tube lens group and a microscope objective lens which are sequentially arranged along the light path;

[0011] The light collecting path includes a microscope objective lens, a tube lens group, a field lens group, a galvanometer group, a dichroic mirror, a condenser group and an optical fiber collecting group which are sequentially arranged along the light path;

[0012] Wherein, the microscope objective lens, tube lens group, field lens group, galvanometer group and dichroic mirror are shared in the imaging light path, excitation light path and collection light path;

[0013] The beam splitter is arranged on the optical path between the tube lens group and the field lens group, and the beam splitter reflects the light path between the tube lens group and the field lens group to the camera;

[0014] The galvanometer mirror group is a controlled mirror group. The galvanometer mirror group in a controlled state controls the incident angle of the laser beam so that the focused light spot on the sample surface on the sample platform moves to scan the sample and stimulate it to generate fluorescence.

[0015] Among them, the fluorescence signal emitted by the sample is converged to the optical fiber collection group along the collection light path;

[0016] The confocal scanning control system is installed inside the detection box and is used to control the galvanometer group to perform controlled movement according to the instructions issued, and to process the optical signals collected by the optical fiber collection group and send them to the PC data processing system;

[0017] The PC data processing system is connected to the detection box for analyzing and processing the single photon signal output by the detection box and generating an image.

[0018] Preferably, the confocal scanning control system includes:

[0019] There are two single-photon detectors for converting optical signals into electrical signals, and the input ends of the two single-photon detectors are connected to the optical fiber collection group through a splitter;

[0020] a core board, communicatively connected to an output terminal of one of the single-photon detectors;

[0021] A galvanometer drive board, used for driving the galvanometer group to perform controlled motion;

[0022] The DAC board is in communication with the core board and is used to convert the instructions sent by the PC data processing system to the core board into electrical signals and send them to the galvanometer drive board.

[0023] Preferably, the core board includes:

[0024] The MCU module is connected to the PC data processing system to analyze the execution instructions received from the PC data processing system and issue the drive commands. The MCU module is connected to the DAC board to generate the drive signals from the drive commands and provide them to the galvanometer drive board to execute the controlled motion.

[0025] Counting module; its input is the output signal of the single-photon detector. After receiving the instruction, the counting module executes the counting function and sends it to the MCU module.

[0026] Preferably, the PC-side data processing system includes a PC host and analysis software configured in the system of the PC host, and the analysis software has the following functions:

[0027] (a) The MCU module feeds the collected signal back to the analysis software, which performs data analysis on the signal and reconstructs the image, thus achieving confocal scanning imaging of the current field of view.

[0028] (b) Set the scanning range, scanning accuracy and scanning speed;

[0029] (c) Real-time feedback of the current counting results transmitted by the core board in the non-scanning state.

[0030] Preferably, an external acquisition card is further included, wherein the input end of the external acquisition card is communicatively connected to the output ends of the two single-photon detectors, and the output end of the external acquisition card is communicatively connected to the PC-side data processing system.

[0031] Preferably, the analysis software also has the following functions:

[0032] (d) Send signals through analysis software to achieve data download and parameter setting;

[0033] (e) The data obtained from the external acquisition card is processed by the analysis software using a local traversal algorithm to count the time difference of the single-photon signal and calculate the second-order correlation function curve.

[0034] Preferably, the confocal optical system further comprises a first mounting base for detachably mounting the beam splitter, and a color filter for filtering out fluorescence can be detachably mounted on the first mounting base;

[0035] When only the beam splitter is installed in the first mounting seat, the imaging optical path is in a wide-field imaging mode;

[0036] When a beam splitter is installed in the first mounting seat and a color filter is installed between the beam splitter and the camera, the imaging light path is a fluorescence imaging mode;

[0037] When the beam splitter is not installed in the first mounting seat, the imaging light path is in a blocking mode.

[0038] Preferably, a condenser lens group is provided between the galvanometer lens group and the optical fiber collection group on the collection light path, and the condenser lens group includes a bandpass filter and a lens sequentially arranged along the collection light path.

[0039] Preferably, a dichroic mirror is provided on the collection light path between the galvanometer group and the condenser group, and a first reflecting mirror is provided on the reflecting light path of the dichroic mirror for reflecting the laser beam emitted by the optical fiber excitation group onto the dichroic mirror.

[0040] Preferably, a confocal single-photon detection method based on galvanometer group scanning analysis is applied to a confocal single-photon detector based on galvanometer group scanning analysis as described above, comprising the following steps:

[0041] Step 1: Widefield positioning of the sample center and sample surface

[0042] Adjust the sample platform with the help of the imaging image obtained by the camera so that the sample to be inspected is in the middle area of ​​the field of view and facing the sample surface;

[0043] Step 2: Scan to find samples;

[0044] Step 2-1: Light signal excitation: Scan the sample through the excitation light path to excite the sample so that it emits fluorescence;

[0045] Step 2-2: Light signal acquisition: The excited fluorescence signal is collected through the acquisition optical path and then transmitted to the confocal scanning control system via the optical fiber acquisition group. The confocal scanning control system performs two-dimensional scanning and obtains a fluorescence confocal scanning image;

[0046] Step 2-3: Double-click the center of the sample in the fluorescence confocal scan image through the software interface to perform rough positioning;

[0047] Step 3: Control the focus spot to move in small steps to the position where the counting result in the sample reaches the highest value.

[0048] Step 4: Collect data through an external acquisition card, and analyze and calculate the output second-order correlation function curve in combination with the PC data processing system.

[0049] Compared with the prior art, the present invention has the following advantages:

[0050] The common focusing optical path system in the present invention adopts a galvanometer group as the core, simplifies the optical path design, retains only the receiving, excitation, and detachable imaging channels, and minimizes the number of lenses to reduce the loss of collected light.

[0051] The present invention places the single-photon detector, core board, galvanometer driver board and DAC board inside the detection box, reduces signal interference while integrating external devices, and concentrates laser adjustment, PC interface, signal output and single-photon detector switch on the front panel, thereby improving the overall coordination of the equipment.

[0052] The confocal single-photon detector PhotonG2 based on galvanometer scanning analysis applied for teaching experiments in this invention is a comprehensive teaching equipment integrating confocal system, illumination system, materials and software algorithms. The equipment can operate under normal temperature and pressure conditions and is suitable for most teaching experimental environments. Its student experiments cover a wide range including: optical imaging experiments, confocal optical path system debugging, galvanometer scanning control, signal acquisition, algorithm processing, equipment maintenance, etc., which has a training effect in all aspects. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Figure 1 This is a schematic diagram of a confocal single-photon detection system based on galvanometer mirror group scanning analysis applied for by the present invention.

[0054] Figure 2 This is a schematic diagram of the three-dimensional structure of the detection box in the confocal single-photon detection system based on the scanning analysis of the galvanometer group applied in the present invention. Figure 1 .

[0055] Figure 3 This is a schematic diagram of the three-dimensional structure of the detection box in the confocal single-photon detection system based on the scanning analysis of the galvanometer group applied in the present invention. Figure 2 .

[0056] Figure 4 It is a schematic diagram of the three-dimensional decomposition structure of a detection box in a confocal single-photon detection system based on scanning analysis of a galvanometer group applied for by the present invention.

[0057] Figure 5 This is a schematic diagram of extended data acquisition in a confocal single-photon detection system based on galvanometer group scanning analysis applied for by the present invention.

[0058] Figure 6 This invention discloses a control interface of analysis software and a scanning and positioning process of NV color center in a confocal single-photon detection system based on scanning analysis of a galvanometer group.

[0059] Figure 7 This invention discloses a control interface of analysis software in a confocal single-photon detection system based on scanning analysis of a galvanometer group and a second NV color center scanning and positioning process.

[0060] Figure 8 This invention discloses a control interface of analysis software in a confocal single-photon detection system based on scanning analysis of a galvanometer group and a third process of NV color center scanning and positioning.

[0061] Figure 9 This invention discloses a control interface of analysis software in a confocal single-photon detection system based on scanning analysis of a galvanometer group and a fourth process of NV color center scanning and positioning.

[0062] Figure 10 The invention relates to an interface for calculating second-order correlation function characteristics of statistical data of analysis software in a confocal single-photon detection system based on scanning analysis of a galvanometer group.

[0063] The numbers in the figure are: 1. Detection box; 2. Galvanometer group; 3. Camera; 4. Fiber excitation group; 5. Fiber acquisition group; 6. Light source module; 7. Sample platform; 8. Microscope objective; 9. Tube lens group; 10. Field lens group; 11. Spectrometer; 12. Single-photon detector; 13. Core board; 14. Galvanometer driver board; 15. DAC board; 16. Laser generator; 17. First interface; 18. Second interface; 19. Third interface; 20. Independent power switch; 21. Laser adjustment panel; 22. Condenser group; 23. Dichroic mirror; 24. First reflector. DETAILED DESCRIPTION

[0064] In order to further understand the features, technical means, and specific objectives and functions achieved by the present invention, the present invention is further described in detail below with reference to the accompanying drawings and specific implementation methods.

[0065] Reference Figure 1-Figure 4 The confocal single-photon detection system based on galvanometer scanning analysis includes a detection box 1, a PC data processing system, a confocal optical path system, a confocal scanning control system, a PC data processing system and an external acquisition card.

[0066] The front panel of the detection box 1 has a communication interface.

[0067] The PC data processing system is connected to the detection box 1 through the communication interface.

[0068] The confocal optical system is installed on the periphery of the detection box 1 and includes an imaging optical path, an excitation optical path, and a collection optical path. The imaging optical path includes a light source module 6, a sample platform 7, a microscope objective lens 8, a tube lens assembly 9, a beam splitter 11, and a camera 3 arranged in sequence along the optical path. The excitation optical path includes a fiber excitation group 4, a first reflector 24, a dichroic mirror 23, a galvanometer lens assembly 2, a field lens assembly 10, a tube lens assembly 9, and the microscope objective lens 8 arranged in sequence along the optical path. The collection optical path includes a microscope objective lens 8, a tube lens assembly 9, a field lens assembly 10, a galvanometer lens assembly 2, a dichroic mirror 23, a condenser lens assembly 22, and a fiber collection group 5 arranged in sequence along the optical path. The microscope objective lens 8, the tube lens assembly 9, the field lens assembly 10, the galvanometer lens assembly 2, and the dichroic mirror 23 are shared by the imaging optical path, the excitation optical path, and the collection optical path. The beam splitter 11 is positioned on the optical path between the tube lens assembly 9 and the field lens assembly 10, reflecting the light from the tube lens assembly 9 and the field lens assembly 10 toward the camera 3. The galvanometer assembly 2 is a controlled mirror assembly. In a controlled state, the galvanometer assembly 2 controls the incident angle of the laser beam, moving the focused spot on the sample surface on the sample platform 7 to scan the sample and stimulate fluorescence. The fluorescence signal emitted by the sample is then converged along the collection optical path to the optical fiber collection assembly 5.

[0069] The confocal scanning control system is installed inside the detection box 1, and is used to control the galvanometer group 2 to perform controlled movement according to the instructions issued, and to process the optical signal collected by the optical fiber collection group 5 and send it to the PC data processing system.

[0070] The PC-side data processing system is connected to the detection box 1 for communication, so as to analyze and process the single photon signal output by the detection box 1 and generate an image.

[0071] The input end of the external acquisition card is communicatively connected to the output ends of the two single-photon detectors 12 , and the output end of the external acquisition card is communicatively connected to the PC-side data processing system.

[0072] The confocal scanning control system includes a single-photon detector 12 , a core board 13 , a galvanometer drive board 14 and a DAC board 15 .

[0073] There are two single-photon detectors 12 for converting optical signals into electrical signals. The input ends of the two single-photon detectors 12 are connected to the optical fiber acquisition group 5 through a splitter. The core board 13 is communicatively connected to the output end of one of the single-photon detectors 12. Specifically, the single-photon detector 12 (SPAD) is a photodetector with single-photon detection capability that can operate in avalanche mode and achieve high-sensitivity detection of extremely low light signals. The single-photon detector 12 is connected to the core board 13 using SMA terminals.

[0074] The galvanometer drive plate 14 is used to drive the galvanometer group 2 to perform controlled motion. Figure 4 As described above, the controlled movement of the galvanometer group 2 is controlled by a motor. The galvanometer group 2 has two galvanometers. Each galvanometer group 2 is installed on the output shaft of an independently controlled motor. The motor drives the galvanometer to rotate around the output shaft to form a controlled movement and thus change the incident angle of the back pupil of the objective lens.

[0075] The DAC board 15 is in communication with the core board 13 and is used to convert instructions sent from the PC data processing system to the core board 13 into electrical signals and send them to the galvanometer drive board 14 .

[0076] The detection box 1 is provided with a fiber laser connected to the fiber excitation group 4 , and the front panel is provided with a laser adjustment panel 21 for setting parameters of the laser emitter.

[0077] The communication interface includes a first interface 17, which is used to connect the core board 13 to the PC data processing system for communication. Specifically, the first interface 17 is a Type-A interface.

[0078] The communication interface includes a second interface 18, which is used for communication between the camera 3 and the PC data processing system. Specifically, the second interface 18 is a Type-C interface.

[0079] The communication interface includes two third interfaces 19, which are used to connect the output ends of the two single-photon detectors 12 to the external acquisition card, which is a time-to-digital converter (TDC) acquisition card. Specifically, the third interfaces 19 are BNC interfaces.

[0080] The front panel of the detection box 1 also has an independent power switch 20 for controlling the power supply of the single-photon detector 12. The single-photon detector 12 must be in a power-off state when not in operation, and when the single-photon detector 12 is powered on, a protective cover needs to be used to cover the entire detection box 1 to shield ambient light.

[0081] The detection box 1 is provided with a laser generator 16 connected to the optical fiber excitation group 4 , and the front panel is provided with a laser adjustment panel 21 for setting parameters of the laser emitter.

[0082] The core board 13 includes an MCU module and a counting module.

[0083] The MCU module is connected to the PC data processing system for communication, and realizes the analysis of the execution instructions received from the PC data processing system and the issuance of the drive commands; the MCU module is connected to the DAC board 15 for communication, and the DAC board 15 generates the drive signal from the drive command and provides it to the galvanometer drive board 14 to execute the controlled motion.

[0084] The input of the counting module is the output signal of the single photon detector 12. After receiving the instruction, the counting module executes the counting function and sends it to the MCU module.

[0085] The PC-side data processing system includes a PC host and analysis software configured in the system of the PC host, and the analysis software has the following functions:

[0086] (a) The MCU module feeds the collected signal back to the analysis software, which performs data analysis on the signal and reconstructs the image, thus achieving confocal scanning imaging of the current field of view.

[0087] (b). Set the scanning range, scanning accuracy and scanning speed.

[0088] (c) Real-time feedback of the current counting result transmitted by the core board 13 in the non-scanning state.

[0089] (d) Send signals through analysis software to achieve data download and parameter setting.

[0090] (e) The data obtained from the external acquisition card is processed by the analysis software using a local traversal algorithm to count the time difference of the single-photon signal and calculate the second-order correlation function curve.

[0091] It should be noted that the logic of the algorithm is as follows:

[0092] Preprocessing: data splicing;

[0093] Data processing: traversal algorithm to obtain the time difference within a domain;

[0094] Algorithm statistics: Calculate the second-order correlation function by statistical time difference.

[0095] The confocal optical system also includes a first mounting block for detachably mounting the beam splitter 11. A color filter for filtering fluorescence can also be detachably mounted on the first mounting block. Specifically, the first mounting block is configured with two inserts: one insert contains the beam splitter 11 and the color filter, and the other insert contains only the beam splitter without the filter.

[0096] When only the beam splitter 11 is installed in the first mounting seat, the imaging optical path is in widefield imaging mode. When the beam splitter 11 is installed in the first mounting seat and a color filter is installed between the beam splitter 11 and 3, the imaging optical path is in fluorescence imaging mode. When the beam splitter 11 is not installed in the first mounting seat, the imaging optical path is in blocking mode. In blocking mode, the controlled movement of the galvanometer group 2 changes the angle at which the laser beam enters the back pupil of the objective lens, forming a Z-shaped path for the focused light spot to scan the sample.

[0097] The beam splitter 11 is a semi-transparent and semi-reflective mirror. The laser beam in the excitation light path can pass through the beam splitter 11 , and the fluorescence emitted by the sample is reflected by the beam splitter 11 and then captured by the camera 3 .

[0098] A condenser lens group 22 is provided between the galvanometer lens group 2 and the optical fiber collection group 5 on the collection optical path. The condenser lens group 22 includes a bandpass filter and a lens sequentially arranged along the collection optical path. Figure 1 The bandpass filter includes a high-pass filter and a low-pass filter, which are used in series to allow light within a specific wavelength range to pass through. The lens is a doublet lens that focuses light within the specific wavelength range onto a spot on the inner core surface of the optical fiber of the optical fiber collection assembly 5.

[0099] A dichroic mirror 23 is provided between the galvanometer group 2 and the condenser group 22 on the collection light path. A first reflector 24 is provided on the reflection light path of the dichroic mirror 23 for reflecting the laser beam emitted by the optical fiber excitation group 4 onto the dichroic mirror 23. Figure 1 In the excitation optical path, the laser beam emitted by the optical fiber excitation group 4 is reflected by the first reflector 24 and then by the dichroic mirror 23 to the galvanometer group 2. In the collection optical path, the light path is reflected by the galvanometer group 2 and then transmitted to the condenser group 22 through the dichroic mirror 23.

[0100] A confocal single-photon detection method based on galvanometer group scanning analysis is applied to a confocal single-photon detection system based on galvanometer group scanning analysis, comprising the following steps:

[0101] Step 1: Widefield positioning of the sample center area and sample surface.

[0102] The sample platform 7 is adjusted with the aid of the imaging image acquired by the camera 3 so that the sample to be inspected is in the middle area of ​​the field of view and faces the sample surface.

[0103] Specifically, confirm that the PC host and camera 3 are connected and then turn on the power, install the microscope objective lens 8; place a sample with a drop of microscope oil (specifically, a single NV diamond) on the sample platform 7 and make the area to be measured roughly located directly below the microscope objective lens 8, install the spectrometer 11 on the first mounting seat, turn on the power of the light source module 6 and adjust it to the appropriate brightness; turn on 3 to set the exposure time and gain to the appropriate size; find the upper surface of the single NV diamond by adjusting the position of the sample platform 7.

[0104] Step 2: Scan for samples.

[0105] Step 2-1: Light signal excitation: Scan the sample through the excitation light path to excite the sample so that it emits fluorescence.

[0106] Specifically, turn off 3, pull out the spectroscope 11, turn on the laser emitter, set the intensity, and excite the sample through the excitation light path.

[0107] Step 2-2: Light Signal Acquisition: The excited fluorescence signal is collected via the acquisition optical path and transmitted via the optical fiber acquisition assembly 5 to the confocal scanning control system. The confocal scanning control system performs a two-dimensional scan and acquires a fluorescence confocal scan image. By controlling the galvanometer angle (i.e., the incident angle at the objective lens' back pupil), a two-dimensional scan is performed in the objective lens focal plane to acquire the fluorescence confocal scan image.

[0108] Specifically, connect the core board 13 to the PC host through the first interface 17; set the scanning time in the analysis software; turn on the independent power switch 20 of the single-photon detector 12, start the continuous acquisition function, and start real-time acquisition of counting results; adjust the sample platform 7 so that the sample is close to the microscope objective lens 8, click "Stop Acquisition" in the analysis software, and set the scanning time, scanning range, and scanning accuracy; click "Point Scan" to obtain a fluorescence confocal scanning image.

[0109] More specifically, the controlled movement of the galvanometer group 2 realizes a specific scanning excitation mode, specifically a Z-shaped route scanning. Since there is a certain lag (physical delay) between the actual displacement of the galvanometer and the input sawtooth wave, there will be certain error data at the starting position of each line (such as Figure 5 As shown in the figure, this design uses an extended acquisition route, that is, sampling starts at the ten sampling points before the actual acquisition position, and finally collects data in a rectangular area. However, during processing, only the required second half of the square area is received, thereby achieving the effect of eliminating artifacts.

[0110] Step 2-3: Double-click the center of the sample in the fluorescence confocal scanning image through the software interface for rough positioning.

[0111] Specifically, observe whether there are scattered bright spots in the fluorescence confocal scanning image and whether the corresponding peak value on the waveform is greater than 40; repeat the "point scan" three times. If there is no obvious change in position and intensity, this is a possible single-photon source.

[0112] Step 3: Control the focus spot to move in small steps to the position where the counting result in the sample reaches the highest value.

[0113] Specifically, on a fluorescence confocal scan image, move the mouse to a bright spot and double-click with the left mouse button. The confocal probe will move to that bright spot. Narrow the scan range, gradually approaching the sample, and double-click the brightest spot for observation. If the spot is a single NV, the reference count value is 30-60. Use continuous acquisition to collect counts in real time, setting the increment to 0.01μm, and use the shift key to maximize the count.

[0114] like Figure 6-Figure 9 As shown, it is the software interface of the analysis software, including a common function area, a classification function area, a result display area, an information feedback area, and a sampling waveform area.

[0115] Step 4: Perform data acquisition through an external acquisition card, and analyze and calculate the output of the second-order correlation function curve in combination with the data processing system on the PC side.

[0116] Step 4-1: Open the analysis software (as Figure 10 shown), set the storage locations of "acquisition card data acquisition" and "data saving", pay attention to the storage path, and download data from the external acquisition card.

[0117] Step 4-2: Select the data to be analyzed, calculate the data to be analyzed, and display the calculation results in the second-order correlation function table;

[0118] Step 4-3: Save the analysis result data as a TXT file, and the storage location is set by "save path selection".

[0119] More specifically, the operation steps of a confocal single-photon detection system based on galvanometer group scanning analysis in this application are as follows: ]>

[0120] Connect the camera 3 to the PC host through the second interface 18, and adjust the optical imaging parameters through the analysis software; double-click the calibration crosshair to assist in optical path calibration; use the analysis software to send control instructions to the core board 13 to make the galvanometer group 2 perform the scanning function, and at the same time send a counting instruction to the core board 13 and count each point during the scanning process; upload the data to the PC host and reconstruct the image through the analysis software; modify the scanning parameters multiple times on the analysis software and cooperate with the software interface of the analysis software (as <|0000264|>3]) to simplify the operation of single-click positioning of the image through chemical control.

[0121] Adjust the scanning parameters, scan multiple times and move in small steps to gradually approach the best acquisition point, adjust the moving step and real-time feedback the counting situation of the current point to facilitate positioning the best position.

[0122] Send an acquisition instruction through the analysis software to start the external acquisition card (time-to-digital converter TDC acquisition card) to acquire the data at the best point, and perform preprocessing of the acquired results (data splicing, data traversal, time difference statistics); the analysis software splices the input data according to the data format to make the two channels corresponding in time, uses the least squares method to subtract the two-channel timestamps in the corresponding window from each other, and performs data statistics that satisfy -M < t < M.

[0123] Obtain the second-order correlation function curve through analysis software statistics: calculate the time difference of each group of single photons, statistically analyze and reconstruct the second-order correlation function and normalize it to verify the single-photon statistical properties.

[0124] The above embodiments merely represent one or more embodiments of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that a person of ordinary skill in the art may make various modifications and improvements without departing from the spirit of the present invention, and these modifications and improvements fall within the scope of protection of the present invention. Therefore, the scope of protection of the present invention shall be determined by the appended claims.

Claims

1. A confocal single-photon detection system based on galvanometer scanning analysis, characterized in that: include: A detection box, the front panel of which has a communication interface; A PC data processing system is connected to the detection box through the communication interface; A confocal optical system is installed on the periphery of the detection box, and the confocal optical system includes an imaging optical path, an excitation optical path, and a collection optical path; The imaging optical path includes a light source module, a sample platform, a microscope objective lens, a tube lens group, a spectroscope and a camera arranged in sequence along the optical path; The excitation light path includes an optical fiber excitation group, a first reflector, a dichroic mirror, a galvanometer group, a field lens group, a tube lens group and a microscope objective lens which are sequentially arranged along the light path; The light collecting path includes a microscope objective lens, a tube lens group, a field lens group, a galvanometer group, a dichroic mirror, a condenser group and an optical fiber collecting group which are sequentially arranged along the light path; Wherein, the microscope objective lens, tube lens group, field lens group, galvanometer group and dichroic mirror are shared in the imaging light path, excitation light path and collection light path; The beam splitter is arranged on the optical path between the tube lens group and the field lens group, and the beam splitter reflects the light path between the tube lens group and the field lens group to the camera; The galvanometer mirror group is a controlled mirror group. The galvanometer mirror group in a controlled state controls the incident angle of the laser beam so that the focused light spot on the sample surface on the sample platform moves to scan the sample and stimulate it to generate fluorescence. Among them, the fluorescence signal emitted by the sample is converged to the optical fiber collection group along the collection light path; The confocal scanning control system is installed inside the detection box and is used to control the galvanometer group to perform controlled movement according to the instructions issued, and to process the optical signals collected by the optical fiber collection group and send them to the PC data processing system; The PC data processing system is connected to the detection box for analyzing and processing the single photon signal output by the detection box and generating an image.

2. The confocal single-photon detection system based on galvanometer scanning analysis according to claim 1, characterized in that: The confocal scanning control system includes: There are two single-photon detectors for converting optical signals into electrical signals, and the input ends of the two single-photon detectors are connected to the optical fiber collection group through a splitter; a core board, communicatively connected to an output terminal of one of the single-photon detectors; A galvanometer drive board, used for driving the galvanometer group to perform controlled motion; The DAC board is in communication with the core board and is used to convert the instructions sent by the PC data processing system to the core board into electrical signals and send them to the galvanometer drive board. The communication interface includes a first interface, which is used to connect the core board to the PC data processing system for communication. The communication interface includes a second interface, which is used for communication connection between the camera and the PC data processing system.

3. The confocal single-photon detection system based on galvanometer scanning analysis according to claim 2, characterized in that: The core board includes: The MCU module is connected to the PC data processing system to analyze the execution instructions received from the PC data processing system and issue the drive commands. The MCU module is connected to the DAC board to generate the drive signals from the drive commands and provide them to the galvanometer drive board to execute the controlled motion. Counting module; its input is the output signal of the single-photon detector. After receiving the instruction, the counting module executes the counting function and sends it to the MCU module.

4. The confocal single-photon detection system based on galvanometer scanning analysis according to claim 1, characterized in that: The PC-side data processing system includes a PC host and analysis software configured in the system of the PC host, and the analysis software has the following functions: (a) The MCU module feeds the collected signal back to the analysis software, which performs data analysis on the signal and reconstructs the image, thus achieving confocal scanning imaging of the current field of view. (b) Set the scanning range, scanning accuracy and scanning speed; (c) Real-time feedback of the current counting results transmitted by the core board in the non-scanning state.

5. The confocal single-photon detection system based on galvanometer scanning analysis according to claim 2, characterized in that: It also includes an external acquisition card, the input end of the external acquisition card is communicatively connected to the output ends of the two single-photon detectors, and the output end of the external acquisition card is communicatively connected to the PC-side data processing system. The communication interface includes two third interfaces, and the two third interfaces are used to connect the output ends of the two single-photon detectors to the external acquisition card for communication. The external acquisition card is a time-to-digital converter.

6. The confocal single-photon detection system based on galvanometer scanning analysis according to claim 5, characterized in that: The analysis software also has the following functions: (d) Send signals through analysis software to achieve data download and parameter setting; (e) The data obtained from the external acquisition card is processed by the analysis software using a local traversal algorithm to count the time difference of the single-photon signal and calculate the second-order correlation function curve.

7. The confocal single-photon detection system based on galvanometer scanning analysis according to claim 1, characterized in that: The confocal optical system further comprises a first mounting base for detachably mounting the beam splitter, and a color filter for filtering out fluorescence can also be detachably mounted on the first mounting base; When only the beam splitter is installed in the first mounting seat, the imaging optical path is in a wide-field imaging mode; When a beam splitter is installed in the first mounting seat and a color filter is installed between the beam splitter and the camera, the imaging light path is a fluorescence imaging mode; When the beam splitter is not installed in the first mounting seat, the imaging light path is in a blocking mode.

8. The confocal single-photon detection system based on galvanometer scanning analysis according to claim 1, characterized in that: A condenser lens group is provided on the light collection path between the galvanometer lens group and the optical fiber collection group. The condenser lens group includes a bandpass filter and a lens sequentially arranged along the light collection path.

9. The confocal single-photon detection system based on galvanometer scanning analysis according to claim 1, characterized in that: A dichroic mirror is provided on the collection light path between the galvanometer group and the condenser group, and a first reflecting mirror is provided on the reflecting light path of the dichroic mirror for reflecting the laser beam emitted by the optical fiber excitation group onto the dichroic mirror.

10. A confocal single-photon detection method based on galvanometer scanning analysis, applied to a confocal single-photon detection system based on galvanometer scanning analysis as claimed in claims 1 to 9, comprising the following steps: Step 1: Widefield positioning of the sample center and sample surface Adjust the sample platform with the help of the imaging image obtained by the camera so that the sample to be inspected is in the middle area of ​​the field of view and facing the sample surface; Step 2: Scan to find samples; Step 2-1: Light signal excitation: Scan the sample through the excitation light path to excite the sample so that it emits fluorescence; Step 2-2: Light signal acquisition: The excited fluorescence signal is collected through the acquisition optical path and then transmitted to the confocal scanning control system via the optical fiber acquisition group. The confocal scanning control system performs two-dimensional scanning and obtains a fluorescence confocal scanning image; Step 2-3: Double-click the center of the sample in the fluorescence confocal scan image through the software interface to perform rough positioning; Step 3: Control the focus spot to move in small steps to the position where the counting result in the sample reaches the highest value. Step 4: Collect data through an external acquisition card, and analyze and calculate the output second-order correlation function curve in combination with the PC data processing system.

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