A picosecond time-resolved laser Raman spectroscopy measurement device and method

Abstract

The present invention relates to a Raman spectroscopy measurement device, specifically to a picosecond time-resolved laser Raman spectroscopy measurement device and method, which solves the technical problems of low time resolution and high cost in existing time-resolved Raman spectroscopy detection; the picosecond time-resolved laser Raman spectroscopy measurement device includes a laser, a first beam adjustment module, a second beam adjustment module, an encoding module, and a collection module; the first beam adjustment module adjusts the emitted light of the laser and then incident it on the sample to be measured; the second beam adjustment module is used to receive the scattered light of the sample to be measured; the encoding module includes a grating spectrometer, a first collimating mirror, a galvanometer unit, a multi-slit encoding template, and a dispersion compensation device arranged in sequence along the outgoing light path of the second beam adjustment module; the grating spectrometer disperses the scattered light emitted by the sample to be measured and emits a spectral band; it realizes reducing the cost of Raman spectroscopy testing and improving the time resolution.

Description

Technical Field

[0001] The present invention relates to a Raman spectroscopy measurement device, and particularly to a picosecond time-resolved laser Raman spectroscopy measurement device and method. Background Art

[0002] Laser Raman spectroscopy is a powerful tool for detecting molecular characteristic information and has been widely applied in fields such as chemical production, biomedicine, environmental protection, and food safety. However, for many samples, laser excitation will generate strong fluorescence signals. In some cases, the intensity of the fluorescence signal may even be several orders of magnitude higher than that of the Raman spectrum, which may cause the weak Raman spectrum to be submerged in the fluorescence background. Especially in aspects such as biomedicine, detection of illegal food additives, and pesticide detection, the fluorescence phenomenon is particularly prominent. To obtain a high-quality Raman spectrum, certain fluorescence suppression measures must be taken.

[0003] In recent years, researchers have proposed some new laser Raman spectroscopy techniques to eliminate or reduce fluorescence; such as Shifted excitation Raman difference spectroscopy (SERDS), that is, two lasers with similar wavelengths are used to respectively excite the sample to be measured to obtain two original Raman spectra, and the two original Raman spectra are subtracted to obtain a differential spectrum; since the fluorescence signal hardly changes with the change of the excitation wavelength, on the contrary, the Raman spectrum will closely follow the change of the excitation wavelength and shift, so in the differential spectrum, the spectral signal of the fluorescence is almost completely eliminated, while the Raman spectrum can be retained, and the Raman spectrum without the fluorescence background can be accurately reconstructed by mathematical methods. The SERDS technique has very high requirements for the stability and consistency during the test process. If there are slight differences in the test conditions of different wavelengths, it may lead to the generation of spurious peaks that do not belong to the sample to be measured during the reconstruction process; in addition, using ultraviolet lasers (wavelength less than 300 nm) or infrared lasers (wavelength greater than 800 nm) as the excitation source will also reduce the fluorescence background to a certain extent, but it is selective for the sample to be measured and may not be applicable to some biological samples to be measured and cultural relics.

[0004] Generally, the fluorescence lifetime of the sample to be measured is in the range of several hundred picoseconds (ps) to several tens of nanoseconds (ns). The generation and duration of Raman spectra are on the ps scale. By using a short-pulse picosecond laser as the light source and setting an appropriate gating time window, Raman spectra and fluorescence signals can be separated and measured separately. During data processing, removing the long-lived fluorescence photon signals can effectively improve the signal-to-noise ratio of Raman spectra. Currently, most existing time-resolved Raman spectra use area detectors such as ICCD and ICMOS to achieve Raman spectral imaging detection, which has high costs and low time resolution, only reaching the ns scale; using a SPAD array can achieve picosecond time-resolved Raman detection, but the SPAD array has low time resolution and high costs. Summary of the Invention

[0005] The object of the present invention is to solve the technical problems of low time resolution and high cost in existing time-resolved Raman spectral detection, and provide a picosecond time-resolved laser Raman spectral measurement device and method to reduce the cost of Raman spectral testing and improve the time resolution.

[0006] To solve the above technical problems, the technical solution adopted by the present invention is as follows:

[0007] A picosecond time-resolved laser Raman spectral measurement device, characterized in that it includes a laser, a first beam adjustment module, a second beam adjustment module, an encoding module, and an acquisition module;

[0008] The first beam adjustment module adjusts the outgoing light of the laser and then irradiates it onto the sample to be measured;

[0009] The second beam adjustment module is used to receive the scattered light of the sample to be measured;

[0010] The encoding module includes a grating spectrometer, a first collimating mirror, a galvanometer unit, a multi-slit encoding template, and a dispersion compensation device arranged in sequence along the outgoing light path of the second beam adjustment module;

[0011] The grating spectrometer disperses the scattered light emitted by the sample to be measured and emits a spectral band;

[0012] The galvanometer unit is used to irradiate the spectral band emitted by the grating spectrometer onto the multi-slit encoding template;

[0013] The multi-slit encoding template is used to encode the spectral band emitted by the galvanometer unit;

[0014] The dispersion compensation device is used to restore the spectral band encoded by the multi-slit encoding template to composite light; the acquisition module includes a single-point detector, a synchronous control unit, and a control computer connected in sequence;

[0015] The single-point detector is located on the outgoing light path of the dispersion compensation device;

[0016] The single-point detector is used to convert the composite light restored by the dispersion compensator into an electrical signal and transmit it to the synchronization control unit;

[0017] The synchronization control unit is used to synchronously collect the laser pulse signal of the laser and the electrical signal converted by the single-point detector and transmit them to the control computer;

[0018] The control computer is used to decode the laser pulse signal and the electrical signal transmitted by the synchronization control unit.

[0019] Further, the first beam adjustment module includes a first mirror, a second mirror, a beam expander, a third mirror, and a fourth mirror sequentially arranged along the laser output optical path;

[0020] The beam expander is used to focus the beam reflected by the second mirror onto the third mirror; the sample to be measured is located in the output optical path of the fourth mirror;

[0021] The second beam adjustment module includes a Cassegrain unit;

[0022] The Cassegrain unit is arranged on the scattered light path of the sample to be measured and is used to collect the scattered light of the sample to be measured.

[0023] Further, the Cassegrain unit includes a concave mirror and a convex mirror sequentially arranged along the scattered light path of the sample to be measured.

[0024] Further, the first beam adjustment module includes a second collimating mirror, a first focusing mirror, and a beam splitter sequentially arranged along the laser output optical path;

[0025] The beam splitter is used to transmit the output light of the first focusing mirror to the sample to be measured and reflect the scattered light of the sample to be measured;

[0026] The second beam adjustment module includes a filter, a first mirror, and a second focusing mirror sequentially arranged along the reflected light of the beam splitter;

[0027] The filter is used to filter out the Rayleigh scattered light generated by the sample to be measured.

[0028] Further, the laser light source is a monochromatic laser; the galvanometer unit is composed of galvanometer X and galvanometer Y; the multi-slit encoding template is an encoding template modulated by Hadamard transform and is composed of a plurality of alternately arranged light-transmitting or light-blocking grooves, and the width of each groove ranges from 5 to 200 μm.

[0029] The present invention also provides a picosecond time-resolved laser Raman spectroscopy measurement method, which is based on the picosecond time-resolved laser Raman spectroscopy measurement device and is characterized in that it includes the following steps:

[0030] Step 1: Electrically connect the laser and the synchronization control unit to the laser power supply respectively;

[0031] Step 2: Use the synchronization control unit to collect the laser pulse signal emitted by the laser.

[0032] Step 3: The first beam adjustment module adjusts the emitted light of the laser to be incident on the sample to be measured.

[0033] Step 4: The second beam adjustment module receives the scattered light of the sample to be measured.

[0034] Step 5: The grating spectrometer splits the scattered light of the sample to be measured and emits a spectral band.

[0035] Step 6: Encode the spectral band

[0036] 6.1) The first collimating mirror collimates the spectral band emitted by the grating spectrometer to form a collimated beam.

[0037] 6.2) Control the movement of galvanometer X and galvanometer Y of the galvanometer unit to deflect the incident collimated beam and direct it to different positions of the multi-slit encoding template.

[0038] 6.3) The multi-slit encoding template modulates and encodes the collimated beam and is incident on the dispersion compensation device.

[0039] 6.4) The dispersion compensation device restores the emitted collimated beam to composite light and couples it into a single-point detector, and the single-point detector converts the composite light into an electrical signal.

[0040] Step 7: Obtain the Raman spectrum signal

[0041] 7.1) The synchronization control unit transmits the laser pulse signal of the laser collected synchronously and the electrical signal of the single-point detector to the control computer.

[0042] 7.2) The control computer decodes to obtain the Raman spectrum signal of the sample to be measured.

[0043] Further, specifically in Step 3: The laser pulse signal emitted by the laser is passed through the first reflecting mirror and the second reflecting mirror, and the reflected light of the second reflecting mirror is optimized in quality by the beam expander and then concentrated and incident on the third reflecting mirror, and is reflected to the measurement sample after passing through the fourth reflecting mirror.

[0044] Specifically, Step 4: Adjust the concave mirror and the convex mirror to focus on the sample to be measured, and reflect the scattered light of the sample to be measured to the grating spectrometer through the concave mirror and the convex mirror. After the grating spectrometer splits the light, it is incident on the first collimating mirror.

[0045] Further, specifically in Step 3: The laser pulse signal emitted by the laser is incident on the beam splitter through the second collimating mirror and the first focusing mirror. The beam splitter transmits the emitted light of the first focusing mirror and reflects it to the filter.

[0046] Step 4 specifically is: After the filter removes the Rayleigh scattered light generated by the sample to be measured, it is incident on the grating spectrometer through the first mirror and the second focusing mirror.

[0047] Further, step 6.3 specifically is:

[0048] 6.3.1) Set the circulant matrix S according to the Hadamard transform matrix;

[0049] 6.3.2) Denote the transmissive grooves of the multi-slit encoding template as 1 and the non-transmissive grooves as 0, and the number of transmissive grooves and non-transmissive grooves of the multi-slit encoding template is equal;

[0050] 6.3.3) Use the galvanometer unit to map the collimated beam to the corresponding positions of the multi-slit encoding template according to the matrix S, and through the dispersion compensator to the single-point detector to obtain the sum Y of the collimated beams;

[0051] 6.3.4) Calculate the matrix X of the Raman spectrum: X = S -1 ·Y.

[0052] Compared with the prior art, the beneficial effects of the technical solution of the present invention are:

[0053] 1. The picosecond time-resolved laser Raman spectroscopy measurement device of the present invention adopts a galvanometer unit, a multi-slit encoding template, a dispersion compensator, a single-point detector, a synchronous control unit and a control computer, effectively filters the fluorescence noise in the Raman spectrum, improves the signal-to-noise ratio of the Raman spectrum, makes the structure complexity of the picosecond time-resolved laser Raman spectroscopy measurement device lower, can realize picosecond time-resolved Raman spectroscopy, and has the advantages of low cost and small volume.

[0054] 2. The picosecond time-resolved laser Raman spectroscopy detection device of the present invention can make the detection distance of the picosecond time-resolved laser Raman spectroscopy measurement device reach more than 10 m through the first mirror, the second mirror, the beam expander, the third mirror, the fourth mirror and the Cassegrain unit, and is applied to explosive detection and dangerous working environments, and can realize remote detection of picosecond time-resolved laser Raman spectroscopy at a safe distance, ensuring the safety of personnel and equipment.

[0055] 3. The picosecond time-resolved laser Raman spectroscopy microscopic measurement device of the present invention adopts a second collimating mirror, a first focusing mirror, a beam splitter, a filter, a first mirror and a second focusing mirror, makes the detection distance of the picosecond time-resolved laser Raman spectroscopy measurement device less than 20 cm, can detect samples to be measured with a particle size in the μm level, and is applied to drug and cultural relic research. Description of the Drawings

[0056] Figure 1 It is a schematic structural diagram of Embodiment 1 in the present invention;

[0057] Figure 2 It is a schematic structural diagram of the second embodiment in the present invention;

[0058] Figure 3 It is a schematic structural diagram of a 16-channel multi-slit encoding template in the first and second embodiments of the present invention;

[0059] Figure 4 It is a schematic structural diagram of the galvanometer unit in the first and second embodiments of the present invention;

[0060] The reference numerals are:

[0061] 1 - Laser power supply, 2 - Laser, 3 - First reflector, 4 - Second reflector, 5 - Beam expander, 6 - Third reflector, 7 - Fourth reflector, 8 - Sample to be measured, 9 - Convex mirror, 10 - Concave mirror, 11 - Grating spectrometer, 12 - First collimator, 13 - Galvanometer X, 14 - Galvanometer Y, 15 - Multi-slit encoding template, 16 - Dispersion compensation device, 17 - Single-point detector, 18 - Synchronous control unit, 19 - Control computer, 20 - First focusing mirror, 21 - Beam splitter, 22 - Filter, 23 - Second focusing mirror, 24 - Second collimator. Detailed implementation manners

[0062] Next, the technical solutions of the present invention will be described clearly and completely in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of them. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0063] In the description of the present invention, it should be noted that the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance.

[0064] Embodiment 1

[0065] As Figure 1 shown, a picosecond time-resolved laser Raman spectroscopy measurement device includes a laser 2, a first beam adjustment module, a second beam adjustment module, an encoding module, and a collection module;

[0066] The laser 2 and the synchronous control unit 18 are respectively electrically connected to the laser power supply 1. The first beam adjustment module adjusts the emitted light of the laser 2 and then irradiates it onto the sample to be measured 8. The first beam adjustment module is sequentially provided with a first reflector 3, a second reflector 4, a beam expander 5, a third reflector 6, and a fourth reflector 7 along the emission optical path of the laser 2. The beam expander 5 is used to concentrate the beam reflected by the second reflector 4 and irradiate it onto the third reflector 6. The sample to be measured 8 is located in the emission optical path of the fourth reflector 7;

[0067] The second beam adjustment module is used to receive the scattered light of the sample 8 to be measured; the second beam adjustment module is provided with a Cassegrain unit; the Cassegrain unit is arranged on the scattered light path of the sample 8 to be measured, and the Cassegrain unit is successively provided with a concave mirror 10 and a convex mirror 9 along the scattered light path of the sample 8 to be measured; it is used to collect the scattered light of the sample 8 to be measured.

[0068] The encoding module is successively provided with a grating spectrometer 11, a first collimator 12, a galvanometer unit, a multi-slit encoding template 15 and a dispersion compensation device 16 along the outgoing light path of the second beam adjustment module; the grating spectrometer 11 disperses the scattered light emitted by the sample 8 to be measured and emits a spectral band; the galvanometer unit is used to direct the spectral band emitted by the grating spectrometer 11 onto the multi-slit encoding template 15; the multi-slit encoding template 15 is used to encode the spectral band emitted by the galvanometer unit; the dispersion compensation device 16 is used to restore the spectral band encoded by the multi-slit encoding template 15 to composite light; the acquisition module is provided with a single-point detector 17, a synchronous control unit 18 and a control computer 19 connected in sequence; the single-point detector 17 is located on the outgoing light path of the dispersion compensation device 16; the single-point detector 17 is used to convert the composite light restored by the dispersion compensation device 16 into an electrical signal and transmit it to the synchronous control unit 18; the synchronous control unit 18 is used to synchronously collect the laser pulse signal of the laser 2 and the electrical signal converted by the single-point detector 17 and transmit them to the control computer 19; the control computer 19 is used to decode the laser pulse signal and the electrical signal transmitted by the synchronous control unit 18.

[0069] Among them, the light source of the laser 2 is monochromatic laser; as Figure 4 shown, the galvanometer unit is composed of a galvanometer X13 and a galvanometer Y14; the multi-slit encoding template 15 is a coding template for Hadamard transform optical modulation, which is composed of a plurality of alternately arranged light-transmitting or light-impermeable grooves, and the width of each groove ranges from 5 to 200 μm.

[0070] The present invention also provides a picosecond time-resolved laser Raman spectroscopy measurement method, based on the picosecond time-resolved laser Raman spectroscopy measurement device, including the following steps:

[0071] Step 1: Electrically connect the laser 2 and the synchronous control unit 18 to the laser power supply 1 respectively;

[0072] Step 2: Use the synchronous control unit 18 to collect the laser pulse signal emitted by the laser 2;

[0073] Step 3: The first beam adjustment module adjusts the outgoing light of the laser 2 to be incident on the sample 8 to be measured;

[0074] The laser pulse signal emitted by the laser 2 passes through the first reflector 3 and the second reflector 4, and the reflected light of the second reflector 4 is optimized in quality by the beam expander 5 and then concentratedly incident on the third reflector 6, and is reflected to the measurement sample after passing through the fourth reflector 7;

[0075] Step 4: The second light beam adjustment module receives the scattered light of the sample 8 to be measured;

[0076] Adjust the concave mirror 10 and the convex mirror 9 to focus on the sample 8 to be measured, and reflect the scattered light of the sample 8 to be measured to the grating spectrometer 11 through the concave mirror 10 and the convex mirror 9. After being dispersed by the grating spectrometer 11, the light is incident on the first collimating mirror 12.

[0077] Step 5: The grating spectrometer 11 disperses the scattered light of the sample 8 to be measured and emits a spectral band;

[0078] Step 6: Encode the spectral band

[0079] 6.1) The first collimating mirror 12 collimates the spectral band emitted by the grating spectrometer 11 to form a collimated light beam;

[0080] 6.2) Control the movement of the galvanometer X13 and galvanometer Y14 of the galvanometer unit to deflect the incident collimated light beam and direct it to different positions of the multi-slit encoding template 15;

[0081] 6.3) The multi-slit encoding template 15 modulates and encodes the collimated light beam and is incident on the dispersion compensation device 16;

[0082] 6.3.1) Set the circulant matrix S according to the Hadamard transform matrix;

[0083] 6.3.2) Denote the light-transmitting grooves of the multi-slit encoding template 15 as 1 and the light-impermeable grooves as 0. The number of light-transmitting grooves and light-impermeable grooves of the multi-slit encoding template 15 is equal;

[0084] 6.3.3) Use the galvanometer unit to map the collimated light beam to the corresponding positions of the multi-slit encoding template 15 according to the matrix S, and through the dispersion compensation device 16 to the single-point detector 17 to obtain the sum Y of the collimated light beams;

[0085] 6.3.4) Calculate the matrix X of the Raman spectrum: X = S -1 ·Y.

[0086] 6.4 The dispersion compensation device 16 restores the outgoing collimated light beam to composite light and couples it into the single-point detector 17. The single-point detector 17 converts the composite light into an electrical signal;

[0087] Step 7: Obtain the Raman spectrum signal

[0088] 7.1) The synchronization control unit 18 transmits the laser pulse signal of the laser 2 and the electrical signal of the single-point detector 17 collected synchronously to the control computer 19;

[0089] 7.2) The control computer 19 decodes to obtain the Raman spectrum signal of the sample 8 to be measured.

[0090] The working principle of the above embodiments is as follows:

[0091] For time-resolved Raman spectroscopy, the fluorescence lifetime of the sample 8 to be measured is usually in the range of several hundred picoseconds (ps) to several tens of nanoseconds (ns), and the generation and duration of Raman spectroscopy are on the ps scale. Using a short-pulse picosecond laser 2 as the light source and setting an appropriate gating time window, the Raman spectrum and fluorescence signal can be separated and measured separately. By removing the long-lived fluorescence photon signal during data processing, the signal-to-noise ratio of the Raman spectrum can be effectively improved.

[0092] The present invention uses a 532 nm picosecond pulsed laser 2 as the excitation light source. After the detection laser exits the laser 2, it is incident on the beam expander 5 through the first mirror 3 and the second mirror 4 to optimize the laser spot size. The optimized beam is incident on the surface of the sample 8 to be measured through the third mirror 6 and the fourth mirror 7; the distance from the sample 8 to be measured to the fourth mirror 7 is 10 m. The concave mirror 10 and the convex mirror 9 of the Cassegrain unit are adjusted by the stepper motor control card to focus the Cassegrain unit on the surface of the sample 8 to be measured; the scattered light on the surface of the sample 8 to be measured is collected by the Cassegrain unit and then dispersed by the grating spectrometer 11. The dispersed spectral band is incident on the galvanometer unit through the collimating mirror. The spectral band is mapped onto the multi-slit encoding template 15 by the galvanometer unit controlled by the servo motor. After the spectral band is encoded by the template, it passes through the dispersion compensation device 16 and is focused by the focusing mirror to the single-point detector 17. The single-point detector 17 converts the composite light generated by the dispersion compensation device 16 into an electrical signal. The electrical signal of the single-point detector 17 is compared with the laser pulse signal by the synchronous control unit 18, and an appropriate gating time is set, and the data after filtering the fluorescence signal is transmitted to the control computer 19.

[0093] Using the single-point detector 17 can transform the time-intensity signal into a spatial-intensity signal. However, the energy corresponding to a single wavelength is very weak, and the noise of the detector is relatively large. If the energy at a single wavelength is detected, it will inevitably lead to a large measurement error. If different spectra are detected in a certain way, the signal-to-noise ratio of the measurement result can be greatly improved. The multi-slit encoding template 15 is used to realize the combined measurement of different wavelengths, so that the radiation of multiple channels reaches the detector at the same time, making the measurement signal much larger than the noise signal, thereby improving the signal-to-noise ratio of the spectrometer system. The multi-slit encoding template 15 consists of a plurality of transmissive or non-transmissive recyclable grooves, each groove having a width of 0.1 mm. The transmissive grooves are denoted as 1, and the non-transmissive grooves are denoted as 0. The number of transmissive grooves and non-transmissive grooves of the multi-slit encoding template 15 is equal. The cyclic matrix S is set according to the Hadamard transform matrix. Each row of the matrix S is generated by shifting the previous row to the left or right. Therefore, once the first row of the matrix S is determined, the entire matrix S is determined. For example Figure 3As shown, a 16-channel multi-slit encoding template 15 is made based on the matrix S with the first row being 1000110101010011. The galvanometer unit is used to map the collimated beam to the corresponding positions of the multi-slit encoding template 15 according to the matrix S, and then through the dispersion compensation device 16 to the single-point detector 17 to obtain the sum Y of the collimated beams; calculate the matrix X of the Raman spectrum: X = S -1 ·Y.

[0094] When the multi-slit encoding template 15 works, the galvanometer unit is used to map the spectral band to the multi-slit encoding template 15, and the projection is controlled by the galvanometer unit to pass through different slits on the multi-slit encoding template 15 in sequence. Finally, the single-point detector 17 collects the composite light generated by the dispersion compensation device 16 and converts it into an electrical signal, which is transmitted to the synchronous control unit 18; the control computer 19 decodes the laser pulse signal and the electrical signal transmitted by the synchronous control unit 18 to obtain the Raman spectrum.

[0095] Embodiment 2

[0096] As Figure 2 shown, the difference between this embodiment and Embodiment 1 is that the first beam adjustment module includes a second collimating mirror 24, a first focusing mirror 20 and a beam splitter 21 arranged in sequence along the outgoing light path of the laser 2; the beam splitter 21 is used to transmit the outgoing light of the first focusing mirror 20 to the sample to be measured 8 and reflect the scattered light of the sample to be measured 8;

[0097] The second beam adjustment module includes a filter 22, a first mirror 3 and a second focusing mirror 23 arranged in sequence along the reflected light of the beam splitter 21; the filter 22 is used to filter out the Rayleigh scattered light generated by the sample to be measured 8.

[0098] The difference between this embodiment and the picosecond time-resolved laser Raman spectroscopy measurement method of Embodiment 1 is that

[0099] Step 3 is specifically: the first beam adjustment module adjusts the laser pulse signal emitted by the laser 2 to be incident on the sample to be measured 8;

[0100] The monochromatic laser emitted by the laser 2 is incident on the beam splitter 21 through the second collimating mirror 24 and the first focusing mirror 20. The beam splitter 21 transmits the outgoing light of the first focusing mirror 20 and reflects it to the filter 22;

[0101] Step 4 is specifically: the second beam adjustment module receives the scattered light of the sample to be measured 8;

[0102] After the filter 22 filters out the Rayleigh scattered light generated by the sample to be measured 8, it is incident on the grating spectrometer 11 through the first mirror 3 and the second focusing mirror 23.

[0103] The rest of the devices and methods in Embodiment 2 are the same as those in Embodiment 1.

[0104] The working principle of the above embodiments is as follows:

[0105] The present invention uses a 532 nm picosecond pulsed laser 2 as an excitation light source. After the detection laser exits from the laser 2, it passes through a second collimating mirror 24, a first focusing mirror 20, and a beam splitter 21 and then focuses on the surface of the sample to be measured 8. The beam splitter 21 enables the detection distance of the picosecond time-resolved laser Raman spectroscopy measurement device to be less than 20 cm. The scattered light on the surface of the sample to be measured 8 is reflected by the beam splitter 21, and the Rayleigh scattered light is filtered by the filter 22, and then coupled to the grating spectrometer 11 after passing through the second focusing mirror 23. The spectral band obtained after the grating spectrometer 11 disperses the light is collimated by the second collimating mirror 24 and then mapped to the multi-slit encoding template 15 through the galvanometer unit. After the spectral band is encoded by the multi-slit encoding template 15, it is focused and coupled to the single-point detector 17 through the dispersion compensation device 16. The single-point detector 17 converts the composite light generated by the dispersion compensation device 16 into an electrical signal. The electrical signal of the single-point detector 17 is compared with the laser pulse signal through the synchronous control unit 18, and an appropriate gating time is set. The data after filtering the fluorescence signal is transmitted to the control computer 19. The control computer 19 decodes the laser pulse signal and the electrical signal transmitted by the synchronous control unit 18 to obtain the Raman spectral signal for microscopic detection of the sample to be measured 8.

Claims

1. A picosecond time-resolved laser Raman spectroscopy measurement device, characterized in that: it includes a laser (2), a first beam adjustment module, a second beam adjustment module, an encoding module, and a collection module; the first beam adjustment module adjusts the emitted light of the laser (2) and then irradiates it onto the sample to be measured (8); the second beam adjustment module is used to receive the scattered light of the sample to be measured (8); the encoding module includes a grating spectrometer (11), a first collimator (12), a galvanometer unit, a multi-slit encoding template (15), and a dispersion compensation device (16) arranged in sequence along the optical path of the light emitted by the second beam adjustment module; the grating spectrometer (11) disperses the scattered light emitted by the sample to be measured (8) and emits a spectral band; the galvanometer unit is used to irradiate the spectral band emitted by the grating spectrometer (11) onto the multi-slit encoding template (15); the multi-slit encoding template (15) is used to encode the spectral band emitted by the galvanometer unit; the dispersion compensation device (16) is used to restore the spectral band encoded by the multi-slit encoding template (15) to composite light; the collection module includes a single-point detector (17), a synchronous control unit (18), and a control computer (19) connected in sequence; the single-point detector (17) is located on the optical path of the light emitted by the dispersion compensation device (16); the single-point detector (17) is used to convert the composite light restored by the dispersion compensation device (16) into an electrical signal and transmit it to the synchronous control unit (18); the synchronous control unit (18) is used to synchronously collect the laser pulse signal of the laser (2) and the electrical signal converted by the single-point detector (17) and transmit them to the control computer (19); the control computer (19) is used to decode the laser pulse signal and the electrical signal transmitted by the synchronous control unit (18).

2. The picosecond time-resolved laser Raman spectroscopy measurement device according to claim 1, characterized in that: the first beam adjustment module includes a first reflecting mirror (3), a second reflecting mirror (4), a beam expander (5), a third reflecting mirror (6), and a fourth reflecting mirror (7) arranged in sequence along the optical path of the light emitted by the laser (2); the beam expander (5) is used to focus the light beam reflected by the second reflecting mirror (4) and irradiate it onto the third reflecting mirror (6); the sample to be measured (8) is located in the optical path of the light emitted by the fourth reflecting mirror (7); the second beam adjustment module includes a Cassegrain unit; the Cassegrain unit is arranged on the scattered light path of the sample to be measured (8) and is used to collect the scattered light of the sample to be measured (8).

3. The picosecond time-resolved laser Raman spectroscopy measurement device according to claim 2, characterized in that: the Cassegrain unit includes a concave mirror (10) and a convex mirror (9) arranged in sequence along the scattered light path of the sample to be measured (8).

4. The picosecond time-resolved laser Raman spectroscopy measurement device according to claim 1, characterized in that: the first beam adjustment module includes a second collimator (24), a first focusing mirror (20), and a beam splitter (21) arranged in sequence along the optical path of the light emitted by the laser (2); The beam splitter (21) is configured to transmit the outgoing light of the first focusing mirror (20) to the sample to be measured (8) and reflect the scattered light of the sample to be measured (8); The second beam adjustment module includes a filter (22), a first mirror (3), and a second focusing mirror (23) arranged in sequence along the reflected light of the beam splitter (21); The filter (22) is configured to filter out the Rayleigh scattered light generated by the sample to be measured (8).

5. A picosecond time-resolved laser Raman spectroscopy measurement device according to any one of claims 1-4, characterized in that: The light source of the laser (2) is monochromatic laser light; The galvanometer unit is composed of a galvanometer X (13) and a galvanometer Y (14); The multi-slit encoding template (15) is an encoding template for Hadamard transform optical modulation, which is composed of a plurality of alternately arranged light-transmitting or light-impermeable grooves, and the width of each groove ranges from 5 to 200 μm.

6. A picosecond time-resolved laser Raman spectroscopy measurement method, based on the picosecond time-resolved laser Raman spectroscopy measurement device according to any one of claims 1 to 5, characterized by comprising the following steps: Step 1: Electrically connect the laser (2) and the synchronous control unit (18) to the laser power supply (1) respectively; Step 2: Use the control unit (18) to collect the laser pulse signal emitted by the laser (2); Step 3: The first beam adjustment module adjusts the outgoing light of the laser (2) to be incident on the sample to be measured (8); Step 4: The second beam adjustment module receives the scattered light of the sample to be measured (8); Step 5: The grating spectrometer (11) disperses the scattered light of the sample to be measured (8) and emits a spectral band; Step 6: Encode the spectral band 6.1) The first collimating mirror (12) collimates the spectral band emitted by the grating spectrometer (11) to form a collimated beam; 6.2) Control the movement of the galvanometer X (13) and the galvanometer Y (14) of the galvanometer unit to deflect the incident collimated beam and direct it to different positions of the multi-slit encoding template (15); 6.3) The multi-slit encoding template (15) modulates and encodes the collimated beam and is incident on the dispersion compensation device (16); 6.4) The dispersion compensation device (16) restores the outgoing collimated beam to composite light and couples it into the single-point detector (17), and the single-point detector (17) converts the composite light into an electrical signal; Step 7: Obtain the Raman spectrum signal 7.1) The synchronous control unit (18) synchronously collects the laser pulse signal of the laser (2) and the electrical signal converted by the single-point detector (17) and transmits them to the control computer (19); 7.2) The control computer (19) performs decoding to obtain the Raman spectrum signal of the sample to be measured (8).

7. A picosecond time-resolved laser Raman spectroscopy measurement method according to claim 6, characterized in that, Specifically in step 3: The laser pulse signal emitted by the laser (2) passes through the first mirror (3) and the second mirror (4), and the reflected light of the second mirror (4) is optimized in quality by the beam expander (5) and then focused and incident on the third mirror (6), and is reflected by the fourth mirror (7) onto the sample to be measured (8); Step 4 specifically includes: adjusting the concave mirror (10) and the convex mirror (9) to focus on the sample to be measured (8), and reflecting the scattered light of the sample to be measured (8) through the concave mirror (10) and the convex mirror (9) to the grating spectrometer (11), and the light after being dispersed by the grating spectrometer (11) is incident on the first collimating mirror (12).

8. A picosecond time-resolved laser Raman spectroscopy measurement method according to claim 6, wherein, Step 3 specifically includes: the laser pulse signal emitted by the laser (2) is incident on the beam splitter (21) through the second collimating mirror (24) and the first focusing mirror (20), and the beam splitter (21) transmits the light emitted by the first focusing mirror (20) and reflects it to the filter (22); Step 4 specifically includes: after the filter (22) filters out the Rayleigh scattered light generated by the sample to be measured (8), it is incident on the grating spectrometer (11) through the first reflecting mirror (3) and the second focusing mirror (23).

9. A picosecond time-resolved laser Raman spectroscopy measurement method according to any one of claims 6-8, wherein, Step 6.3 specifically includes: 6.3.1) Setting the circulant matrix S according to the Hadamard transform matrix; 6.3.2) Denote the light-transmitting grooves of the multi-slit encoding template (15) as 1 and the non-light-transmitting grooves as 0, and the number of light-transmitting grooves and non-light-transmitting grooves of the multi-slit encoding template (15) is equal; 6.3.3) Using the galvanometer unit to map the collimated beam to the corresponding positions of the multi-slit encoding template (15) according to the matrix S, and through the dispersion compensator (16) to the single-point detector (17) to obtain the sum Y of the collimated beams. 6.3.4) Calculate the matrix X of the Raman spectrum: X = S -1 ·Y.

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