A line focusing mode planetary laser raman spectrum acquisition device and method

Abstract

The present application relates to a kind of line focusing mode planetary laser raman spectrum acquisition device and method, the device includes laser emission unit, beam expander unit, two-way optical element, line focusing unit, raman spectrum signal separation and acquisition unit, spectrometer and computer control unit.Wherein, laser emission unit outputs laser beam, beam expander unit, two-way optical element are placed in the light path direction of laser beam in turn, line focusing unit is placed in the emission direction of beam expander unit and the light path reflection direction of two-way optical element, raman spectrum signal separation and acquisition unit and spectrometer unit are placed in the transmission direction of two-way optical element in turn, computer control unit is connected with spectrometer, laser emission unit.This application can realize the line focusing laser raman spectrum signal acquisition and output single total spectrum or multiple point spectrum, provide new ideas for realizing the rapid, efficient acquisition of lunar mineral composition, provide more efficient detection method for in-situ detection of planetary surface material composition.

Description

Technical Field

[0001] This invention belongs to the field of spectral measurement technology, and particularly relates to a planetary laser Raman spectroscopy acquisition device and method in line focusing mode. Background Technology

[0002] Obtaining precise mineralogical and major chemical information from lunar and planetary samples is a key task in deep space exploration. Raman spectroscopy, as a rapid, accurate, and efficient molecular spectroscopy tool, has already been deployed on Mars rovers to obtain the composition of materials on the Martian surface and will soon be used for scientific exploration activities on the Moon, Phobos, Deimos, and other celestial bodies. Raman spectroscopy can accurately identify the composition of solid, liquid, or gaseous substances, especially for rock or soil samples, providing information on their mineral content and structure, offering significant advantages over other spectroscopic detection techniques. Raman spectra have sharp peaks and fixed characteristic peak positions; only minerals with specific crystal structures produce Raman scattering light at specific frequencies, hence it is also known as a mineral "fingerprint" identification technology. Furthermore, Raman spectroscopy is simple to operate, fast to analyze, and requires no sample pretreatment, making it of significant application value and potential in the field of deep space exploration.

[0003] Currently, Raman spectrometers used for analyzing the composition of samples from the Moon and Mars primarily employ a point-focusing mode. A laser beam is focused onto the surface of the sample as a circular spot, exciting Raman scattering signals from a tiny region at that spot. However, for lunar and terrestrial planetary samples, the mineral composition is unevenly distributed, typically consisting of aggregates of various minerals. Therefore, whether in laboratory research or in-situ planetary exploration applications, Raman detection of samples tends to rely on multi-point scanning. The same sample needs to be irradiated multiple times at different locations to obtain more complete information on mineral types and distribution. The disadvantage of this method is its time-consuming nature; analyzing a single sample often requires collecting hundreds of Raman spectral data points, significantly extending the execution time of planetary surface spectral exploration missions. Furthermore, the need for multi-point, precise detection places certain demands on the pointing accuracy and lifespan of the laser direction-changing mechanism. These limitations are unfavorable for deep space exploration missions with strict constraints on detection time and component lifespan. In addition, the material composition of lunar and planetary samples is highly heterogeneous, and micro-point detection can easily miss areas of interest or abnormal composition in the sample, making it difficult for researchers to truly grasp information such as the distribution and content of the material composition of the sample. Summary of the Invention

[0004] The purpose of this invention is to solve one of the above-mentioned technical problems and to provide a planetary laser Raman spectroscopy acquisition device and method in line focusing mode.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] A planetary laser Raman spectroscopy acquisition device with line focusing mode, comprising:

[0007] Laser emitting unit: used to output a laser beam and adjust the power of the laser beam;

[0008] Beam expander unit: Located in the emission direction of the laser emitting unit, used to keep the laser beam collimated and change the diameter of the laser beam;

[0009] Line focusing unit: Located along the optical path of the laser beam in the output direction of the beam expander unit, the line focusing unit includes a cylindrical mirror array and a focusing lens, used to shape the laser beam into an ideal focal line with a high aspect ratio and uniform light intensity distribution.

[0010] Sample to be tested: set at the focal point of the focusing lens; the laser beam passes through the cylindrical mirror array and the focusing lens in sequence and then illuminates the sample to be tested, exciting linear Raman scattered light on the surface of the sample to be tested. The Raman scattered light is reflected to the focusing lens, which is also used to collimate the Raman scattered light.

[0011] Two-way beam splitter: It is set between the cylindrical mirror array and the focusing lens along the optical path of the laser beam. It is used to reflect the laser beam that has passed through the cylindrical mirror array to the focusing lens and transmit the Raman scattered light excited by the laser beam on the surface of the sample to be tested.

[0012] Raman spectroscopy signal separation and acquisition unit: The light path of the Raman scattered light after collimation by the focusing lens is set in the transmission direction of the two-dimensional beam splitter to focus the Raman scattered light and eliminate Rayleigh scattered light excited by the laser beam on the surface of the sample to be tested;

[0013] Spectrometer: Located at the focal point of the Raman scattered light focused by the Raman spectral signal separation and acquisition unit, it is used to receive the focused Raman scattered light and convert the Raman scattered light signal into a Raman scattered electrical signal; The spectrometer is equipped with a CCD detector, and the linear Raman scattered light signal focused at the front end of the spectrometer slit corresponds one-to-one with each row of pixels of the CCD detector, so as to realize the output of multiple point spectra on a single linear Raman scattered light spot;

[0014] Computer control unit: electrically connected to the laser emitting unit, used to adjust the laser emission parameters of the laser emitting unit; electrically connected to the spectrometer, used to adjust the spectral acquisition parameters of the spectrometer and the operating parameters of the area array CCD detector. At the same time, it is also used to acquire the Raman scattering electrical signal output by the spectrometer, and to draw a single Raman total spectrum or multiple Raman point spectrum excited by a single linear laser beam spot on the surface of the sample under test based on the acquired Raman scattering electrical signal.

[0015] In some embodiments of the present invention, the cylindrical lens array includes multiple elongated cylindrical unit lenses with the same length, width and radius of curvature. The multiple elongated cylindrical unit lenses are arranged in parallel. Each cylindrical unit lens cooperates with a focusing lens to focus the laser beam incident on the cylindrical unit lens into a linear light spot. The focal line light intensity produced by adjacent cylindrical unit lenses is opposite and they compensate and superimpose with each other. The focal lines produced by all cylindrical unit lenses are superimposed to form an ideal focal line with uniform light intensity distribution.

[0016] The focal length L of an ideal focal line conforms to the following formula:

[0017] L=D*f / (n*f c );

[0018] Where D is the diameter of the incident laser spot, f is the focal length of the focusing lens, and n is the number of unit cylindrical lenses. c This is the focal length of the single cylindrical lens.

[0019] In some embodiments of the present invention, the Raman spectral signal separation and acquisition unit includes a high-pass filter and an achromatic triplet lens arranged sequentially along the optical path of the Raman scattered light transmitted through the two-way beam splitter. The high-pass filter is used to filter Rayleigh scattered light excited by the laser beam on the surface of the sample to be tested, and the achromatic triplet lens is used to eliminate the aberrations of the Raman scattered light transmitted by the high-pass filter. The unit also focuses the Raman scattered light transmitted by the high-pass filter and couples it into the spectrometer.

[0020] In some embodiments of the present invention, the spectrometer collimates the focused Raman scattered light into parallel light and disperses light of different wavelengths into different angles through a grating, focusing it onto different positions of the area array CCD detector to form multiple image points;

[0021] The area array CCD detector measures the light intensity of each wavelength image point and converts the Raman scattered light signal into a Raman scattered electrical signal output. The Raman scattered electrical signal includes the total Raman spectrum data of a single line laser beam spot excited by the area array CCD detector under different operating parameters, or the spectrum data of multiple Raman points excited by a single line laser beam spot.

[0022] In some embodiments of the present invention, the computer control unit includes a laser adjustment module, a spectrometer adjustment module, and a Raman spectrum plotting module;

[0023] The laser adjustment module is used to adjust the laser emission parameters of the laser emitting unit;

[0024] The spectrometer adjustment module is used to adjust the spectral acquisition parameters of the spectrometer and the operating parameters of the area array CCD detector.

[0025] The Raman spectroscopy plotting module is used to acquire the Raman scattering electrical signals output by the spectrometer and plot the corresponding Raman spectra based on the single total Raman spectral data or multiple Raman point spectral data output by the spectrometer.

[0026] In some embodiments of the present invention, the laser emitting unit includes a laser, an optical isolator, a laser attenuator, and a reflector; the optical isolator is disposed at the output port of the laser to prevent reflected light from returning to the laser; the laser attenuator is disposed in the output optical path of the optical isolator to change the energy of the laser beam; and the reflector is disposed in the output optical path of the laser attenuator to change the propagation direction of the laser beam.

[0027] In some embodiments of the present invention, the beam expander unit includes a negative lens and a positive lens arranged sequentially along the optical path of the laser beam. By changing the relative distance between the negative lens and the positive lens, the magnification and focal length of the beam expander unit are adjusted.

[0028] Some embodiments of the present invention further provide a method for acquiring planetary laser Raman spectroscopy in line focusing mode, comprising the following steps:

[0029] S1: Start the computer control unit and laser emission unit. Adjust the laser emission parameters of the laser emission unit through the computer control unit. The laser emission unit outputs a collimated laser beam, which enters the beam expander unit after being emitted.

[0030] S2: Adjust the beam expander unit to change the magnification and focal length of the beam expander unit so that the laser beam is incident on the line focusing unit with a suitable spot size;

[0031] S3: Place the sample to be tested at the focusing position of the focusing lens in the line focusing unit; the line focusing unit shapes the laser beam into a focused linear spot with a high aspect ratio and uniform intensity distribution to illuminate the sample to be tested, and excites Rayleigh scattering and Raman scattering signals of the sample to be tested within the spot area.

[0032] S4: The Rayleigh scattering and Raman scattering signals of the sample to be tested return along the original optical path, pass through the focusing lens of the line focusing unit and the two-dimensional beam splitter in sequence, and then enter the Raman spectral signal separation and acquisition unit; the Raman spectral signal separation and acquisition unit filters out the Rayleigh scattering signal and eliminates the aberration of the Raman scattering signal, then focuses the Raman scattering signal and couples it into the spectrometer.

[0033] S5: Adjust the spectral acquisition parameters of the spectrometer unit and the operating parameters of the area array CCD detector in the spectrometer through the computer control unit to acquire single Raman total spectral data or multiple Raman point spectral data corresponding to a single linear Raman scattering light spot, and draw the corresponding Raman spectrum based on the acquired single Raman total spectral data or multiple Raman point spectral data.

[0034] In some embodiments of the present invention, the following steps are also included:

[0035] Divide the surface of the sample to be tested into n test points;

[0036] The computer control unit adjusts the operating parameters of the area CCD detector in the spectrometer. The area CCD detector divides a single line spot into n point spots based on n test points on the surface of the sample to be tested. Based on the n point spectra after division, the data of all the Raman point spectra collected are merged to output the n Raman point spectrum data corresponding to the n point spots.

[0037] In some embodiments of the present invention, the method for adjusting the beam expander unit in step S2 includes:

[0038] Adjusting the relative distance between the negative and positive lenses in the beam expander unit changes the magnification and focal length of the beam expander unit.

[0039] The beneficial effects of this invention are as follows:

[0040] 1. This invention applies an optical shaping element cylindrical mirror array to a Raman spectroscopy detection system. By superimposing and compensating the focusing lines of multiple unit cylindrical mirrors, a high-quality linear light spot with good light uniformity is formed. This ensures that different positions on the surface of the sample can obtain similar irradiation conditions in a single analysis during the detection process, guaranteeing the consistency and comparability of laser excitation conditions for samples at different sampling points. In addition, compared with a point light spot, a linear light spot can cover a larger sample area in a single irradiation, while exciting more Raman scattered light signals from more molecules in a larger range of the sample. This reduces the number of laser irradiations required for scanning a single sample point, improves the acquisition efficiency of the Raman spectroscopy detection system, and avoids missing regions of interest or abnormal composition in the sample.

[0041] 2. This invention eliminates aberrations such as chromatic aberration and spherical aberration in Raman spectral signal separation and acquisition unit by setting an achromatic triplet lens. This achieves a one-to-one correspondence between the line spot focused on the sample surface and the Raman signal line spot focused on the spectrometer slit. This allows the spectrometer to output not only a single total Raman spectrum excited by a single line spot, but also multiple point spectra under line focusing, so as to more comprehensively understand the spatial distribution of different minerals on the sample surface.

[0042] 3. The Raman spectroscopy acquisition device and acquisition method provided by this invention can not only obtain the material composition information of the sample to be tested more accurately, but also greatly save the detection time, improve the detection efficiency and accuracy, and reduce the consumption of instrument life and engineering resources. It can better serve the deep space exploration engineering missions with strict requirements on detection time, power consumption and life, and provide a more efficient and faster detection method for in-situ detection of the material composition of planetary surfaces. Attached Figure Description

[0043] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0044] Figure 1 This is a schematic diagram of the planetary laser Raman spectroscopy acquisition device with line focusing mode provided by the present invention.

[0045] Figure 2 This is a schematic diagram of the linear focusing unit in the planetary laser Raman spectroscopy acquisition device with linear focusing mode provided by the present invention.

[0046] Wherein, (a) is the structural block diagram, and (b) is the Zemax simulation entity diagram;

[0047] Figure 3 The Lighttools simulation diagram shows the laser optical path from the line focusing unit to the sample under test in the planetary laser Raman spectroscopy acquisition device of the line focusing mode provided by the present invention.

[0048] Among them, (a) is the solid image and (b) is the line-focused spot image;

[0049] Figure 4 A Lighttools simulation diagram of the spot light spot in the Raman signal collection optical path of the planetary laser Raman spectroscopy acquisition device in line focusing mode provided by the present invention;

[0050] Among them, (a) is the solid image and (b) is the light spot image at the front end of the spectrometer slit;

[0051] Figure 5 A flowchart of the planetary laser Raman spectroscopy acquisition method in line focusing mode provided by the present invention;

[0052] Figure 1 In the attached figures, the labels are:

[0053] 1. Laser emitting unit; 101. Laser; 102. Optical isolator; 103. Laser attenuator; 104. Mirror.

[0054] 2. Beam expander unit, 201. Negative lens, 202. Positive lens;

[0055] 3. Two-way beam splitter;

[0056] 4. Line focusing unit; 401. Cylindrical mirror array; 402. Focusing lens;

[0057] 5. Sample to be tested;

[0058] 6. Raman spectroscopy signal separation and acquisition unit, 601, high-pass filter, 602, achromatic cemented triplet lens;

[0059] 7. Spectrometer;

[0060] 8. Computer control unit. Detailed Implementation

[0061] To make the objectives, technical solutions, and advantages of this application clearer, the application is described and illustrated below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application. All other embodiments obtained by those skilled in the art based on the embodiments provided in this application without inventive effort are within the scope of protection of this application.

[0062] It should be noted that the terminology used herein is for the purpose of describing particular implementations only and is not intended to limit the exemplary implementations according to this application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. Furthermore, it should be understood that the terms “comprising” and “having”, and any variations thereof, are intended to cover non-exclusive inclusion, for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such process, method, product, or apparatus.

[0063] Where there is no conflict, the embodiments and features in the embodiments of the present invention can be combined with each other.

[0064] The technical solution of the present invention will be described in detail below with reference to specific embodiments and accompanying drawings.

[0065] As attached Figure 1-4 As shown, in an illustrative embodiment of a planetary laser Raman spectroscopy acquisition device with line focusing mode according to the present invention, the acquisition device includes a laser emitting unit 1, a beam expander unit 2, a line focusing unit 4, a sample to be tested 5, a two-dimensional beam splitter 3, a Raman spectral signal separation and acquisition unit 6, a spectrometer 7, and a computer control unit 8.

[0066] The laser emitting unit 1 is equipped with a laser 101 for outputting a laser beam and adjusting the power of the laser beam. The laser emitting unit 1 uses a pulsed laser, which emits a Gaussian beam with a wavelength of 532nm, a repetition rate of 1kHz, and a pulse width of 10ns.

[0067] The beam expander unit 2 is positioned in the emission direction of the laser emitting unit 1 to maintain laser beam collimation and change the diameter of the laser beam. In this embodiment, the magnification of the beam expander unit 2 is 1.4X, the focal length is 3m, and the antireflection coating in the beam expander unit is 532nm.

[0068] The line focusing unit 4 is positioned along the optical path of the laser beam in the output direction of the beam expander unit 2. The line focusing unit 4 includes a cylindrical mirror array 401 and a focusing lens 402.

[0069] The cylindrical lens array 401 is set along the optical path of the laser beam to set the emission direction of the beam expander unit 2. The cylindrical lens array 401 is composed of multiple long strip-shaped unit cylindrical lenses arranged in parallel. Each sub-unit cylindrical lens focuses the laser incident on it along the main axis direction, but does not focus in the direction perpendicular to the main axis direction, forming a sub-focal line. The energy distribution of the symmetrical sub-focal lines is exactly opposite. The superposition of multiple sub-focal lines can shape the circular laser beam into an ideal focal line with a high aspect ratio and uniform light intensity distribution.

[0070] A dichroic beam splitter 3 is disposed between the cylindrical mirror array 401 and the focusing lens 402 along the optical path of the laser beam. The dichroic beam splitter 3 is used to reflect the laser beam passing through the cylindrical mirror array 401 to the focusing lens 402, and also to transmit the Raman scattered light excited by the laser beam on the surface of the sample 5 under test. In this embodiment, the dichroic beam splitter 3 is a 532nm dichroic beam splitter 3 and is placed at 45° to the optical path direction of the beam expander unit 2, reflecting the 532nm pulsed laser beam to the focusing lens 402 in the line focusing unit 4, and is capable of transmitting Raman scattered light from 535nm to 780nm.

[0071] A focusing lens 402 is positioned in the reflection direction of the dihedral beam splitter 3. The focusing lens 402, in conjunction with the cylindrical mirror array 401, focuses an ideal focal line with a high aspect ratio and uniform light intensity distribution. It also serves to standardize the Raman scattered light excited from the surface of the sample 5.

[0072] The sample to be tested 5 is set at the focal point of the focusing lens 402; the laser beam passes through the cylindrical mirror array 401 and the focusing lens 402 in sequence and then illuminates the sample to be tested 5, exciting linear Raman scattering and Rayleigh scattering on the surface of the sample to be tested 5. The Raman scattering and Rayleigh scattering are reflected to the focusing lens 402 and collimated by the focusing lens 402.

[0073] Because the Raman scattered light signal is weak, it is easily obscured by the Rayleigh scattered light signal, affecting the quality of the Raman scattered signal. Therefore, it is necessary to remove the Rayleigh scattered light signal. Thus, a Raman spectral signal separation and acquisition unit 6 is set along the transmission direction of the two-dimensional beam splitter 3 along the optical path of the Raman scattered light collimated by the focusing lens 402. This unit is used to focus the Raman scattered light and eliminate the Rayleigh scattered light excited by the laser beam on the surface of the sample 5.

[0074] Spectrometer 7 is positioned at the focal point of the Raman scattered light focused by Raman spectral signal separation and acquisition unit 6. It receives the focused Raman scattered light and converts the Raman scattered light signal into a Raman scattered electrical signal. Spectrometer 7 contains an area-array CCD detector. The linear Raman scattered light signal focused at the front end of the slit in spectrometer 7 corresponds one-to-one with each row of pixels on the area-array CCD detector, enabling the output of multiple point spectra on a single linear Raman scattered light spot.

[0075] The computer control unit 8 is connected to the laser 101, spectrometer 7, and area CCD detector via data cables. It includes a laser 101 adjustment module, a spectrometer 7 adjustment module, and a Raman spectroscopy plotting module. The laser 101 adjustment module adjusts the laser emission parameters of the laser emission unit 1, such as energy and frequency. The spectrometer 7 adjustment module adjusts the spectral acquisition parameters of the spectrometer 7, such as integration time, Readout-Mode, Regions of Interest, accumulation count, and spectral detection range, as well as the operating parameters of the area CCD detector. The Raman spectroscopy plotting module acquires the Raman scattering electrical signal output by the spectrometer 7 and plots the corresponding single-line Raman total spectrum or multiple Raman point spectrum based on the single-line Raman total spectrum data or multiple Raman point spectrum data output by the spectrometer 7.

[0076] It should be noted that in this embodiment, the pulsed laser used by the laser emitting unit 11 is a green laser with a wavelength of 532nm. However, by selecting appropriate laser emitting unit 1, beam expander unit 2, two-way beam splitter 3, and Raman spectral signal separation and acquisition unit 6, the principle of the present invention can also be applied to the use of lasers of other wavelengths.

[0077] In some embodiments of the present invention, the laser emitting unit 1 further includes an optical isolator 102, a laser attenuator 103, and a reflector 104. The optical isolator 102 is disposed at the output port of the laser 101 to prevent reflected light from returning to the laser 101, thereby protecting the laser 101. The laser attenuator 103 is disposed in the output optical path of the optical isolator 102 to change the energy of the laser beam. The reflector 104 is disposed at 45° in the output optical path of the laser attenuator 103 to reflect the laser beam that passes sequentially through the optical isolator 102 and the laser attenuator 103, thereby changing the propagation direction of the laser beam and reflecting it to the beam expander unit 2.

[0078] In some embodiments of the present invention, the beam expander unit 2 includes a negative lens 201 and a positive lens 202 arranged sequentially along the optical path of the laser beam. Since the laser beam diverges during transmission, the magnification and focal length of the beam expander unit 2 can be changed by adjusting the relative distance between the negative lens 201 and the positive lens 202, thereby obtaining a collimated laser beam. The collimated laser beam with a large cross-sectional diameter emitted from the laser emitting unit 1 is incident on the center of the negative lens 201, diverges to a larger diameter at the center of the positive lens 202, and then contracts back into collimated light. The positive and negative lenses 201 achieve the function of changing the beam diameter of the laser beam and keeping it collimated by dividing it by the sum of its focal lengths.

[0079] In some embodiments of the present invention, the cylindrical lens array 401 includes multiple elongated cylindrical unit lenses with the same length, width, and radius of curvature. These elongated cylindrical unit lenses are arranged in parallel. Each cylindrical unit lens, together with the focusing lens 402, focuses the light beam incident on it into a linear spot. Although the light intensity of this focal line is not uniform, the light intensity of the focal line produced by its symmetrical cylindrical unit lens is exactly opposite. The two complement each other and superimpose, thus forming a focal line with relatively uniform light intensity. Finally, all the focal lines formed by the cylindrical unit lenses and the focusing lens 402 are superimposed to form an ideal focal line with high light intensity uniformity. (See attached image) Figure 3 As shown, attached Figure 3 This is a Lighttools simulation diagram of the laser optical path from the line-focusing unit to the sample in a planetary laser Raman spectroscopy acquisition device in line-focusing mode. (See attached image.) Figure 3 It can be seen that the laser beam uniformity on the surface of sample 5 is relatively high.

[0080] The focal length L of the ideal focal line is determined by the diameter of the incident laser spot, the number of unit cylindrical lenses, the focal length of the unit cylindrical lenses, and the focal length of the focusing lens 402, and conforms to the following formula:

[0081] L=D*f / (n*f c );

[0082] Where D is the diameter of the incident laser spot, f is the focal length of the focusing lens 402, and n is the number of unit cylindrical lenses. c The focal length of the unit cylindrical lens is given. The width d of the unit cylindrical lens satisfies d = D / n. By changing the above parameters, focal lines of different lengths can be obtained to meet more detection requirements. In this embodiment, the diameter of the incident laser spot is 7mm, the focal length of the focusing lens 402 is 100mm, the width of the unit cylindrical lens is 0.5mm, and the focal length of the unit cylindrical lens is 10mm, resulting in a focal line with a length of 5mm and a width of approximately 50µm.

[0083] In some embodiments of the present invention, the Raman spectral signal separation and acquisition unit 6 includes a high-pass filter 601 and an achromatic cemented triplet lens 602 arranged sequentially along the optical path of the Raman scattered light transmitted through the dihedral beam splitter 3. The high-pass filter 601 only allows the Raman scattered light signal to pass through, filtering Rayleigh scattered light excited by the laser beam on the surface of the sample 5. The achromatic cemented triplet lens 602 is disposed between the high-pass filter 601 and the spectrometer unit 7. This achromatic cemented triplet lens 602 can be used to eliminate aberrations such as chromatic aberration and spherical aberration in the Raman scattered light, ensuring a one-to-one correspondence between the linear light spot on the surface of the sample 5 and the Raman signal line light spot at the front end of the slit of the spectrometer 7, achieving the output of multiple point spectra under line focusing. It can also focus the collimated Raman scattered light and input it to the spectrometer unit 7. (See attached...) Figure 4 As shown, attached Figure 4 This is a Lighttools simulation image of the spot light pattern in the Raman signal collection optical path of a planetary laser Raman spectroscopy acquisition device in line-focusing mode, provided by [attached image]. Figure 4 It can be seen that the laser line spot on the surface of the sample 5 to be tested corresponds one-to-one with the Raman signal line spot focused to the front end of the slit of the spectrometer 7.

[0084] In some embodiments of the present invention, the spectrometer 7 employs an area-array CCD detector structure, and this area-array CCD detector is a CCD camera. The spectrometer 7 first collimates the focused Raman scattered light into parallel light, and then disperses the light of different wavelengths into different angles through a grating, focusing it onto different positions of the CCD camera to form a series of image points. The CCD camera measures the light intensity of each wavelength image point after dispersion and converts the Raman scattered light signal into a Raman scattered electrical signal for output. The linear Raman signal focused at the front end of the slit of the spectrometer 7 corresponds one-to-one with each row of pixels of the CCD camera. Therefore, in addition to a single total Raman spectrum, the present invention can also output multiple point spectra on a single line spot. The Raman scattered electrical signal includes the single total Raman spectrum data or the multiple Raman point spectrum data excited by a single linear laser beam spot on the surface of the sample 5 under different operating parameters acquired by the CCD camera.

[0085] In some embodiments of the present invention, the computer control unit 8 includes a laser 101 adjustment module, a spectrometer adjustment module, and a Raman spectroscopy plotting module.

[0086] The laser 101 adjustment module is used to adjust the laser emission parameters of the laser emitting unit 1.

[0087] The spectrometer adjustment module is the spectrometer control software running in the computer control unit 8, used to adjust the spectral acquisition parameters of the spectrometer 7 and the operating parameters of the area array CCD detector.

[0088] When the Readout-Mode of the area array CCD detector is set to Frame Transfer and the Regions of Interest is set to Rows Binned (1024×1), a single Raman total spectrum excited by a single linear laser beam spot on the surface of the sample 5 can be output. When the Readout-Mode of the area array CCD detector is set to Full Frame and the Regions of Interest is set to Full Sensor (1024×256), multiple Raman point spectra excited by a single linear laser beam spot on the surface of the sample 5 can be output, that is, 256 Raman point spectrum data can be read out. The 256 Raman point spectra are superimposed together to form a single Raman total spectrum. Furthermore, in the Frame Frame mode of this area array CCD detector, setting the Regions of Interest to Full Sensor, Binned (1024×256) allows for the division of the linear light spot into the number of point spots. For example, dividing the linear light spot into n point spots allows for the merging of multiple data points from the 256 point spectra, resulting in the output of n Raman point spectra. Here, n can be determined based on the number of test points on the surface of the sample 5. By dividing the test points and outputting multiple Raman point spectrum data, the two-dimensional profile distribution of different minerals in the sample 5 can be obtained, thus allowing for the deduction of the formation environment of the sample 5.

[0089] The Raman spectroscopy plotting module is used to acquire the Raman scattering electrical signal output by spectrometer 7, and plot the corresponding Raman spectrum based on the single total Raman spectrum data or multiple Raman point spectrum data output by spectrometer 7.

[0090] In this embodiment, the computer control unit 8 is able to store the acquired Raman spectral data, and the computer control unit 8 also includes a human-computer interaction screen to adjust the parameters of the laser emitting unit 1, the spectrometer 7 and the area array CCD detector, as well as to view the acquired Raman spectral data and the plotted Raman spectrum in real time.

[0091] The specific working process of the planetary laser Raman spectroscopy acquisition device with line focusing mode provided by the present invention is as follows: The laser 101 of the laser emitting unit 1 is turned on, and the laser 101 outputs a 532nm wavelength pulsed laser beam. When the laser beam is emitted, it passes through the optical isolator 102 and the laser attenuator 103, and is reflected by the reflector 104 to change the direction of the light path before entering the beam expander unit 2. A collimated beam is formed and incident at 45° onto the cylindrical mirror array 401 in the line focusing unit 4, splitting the beam into multiple sub-beams to the dihedral beam splitter 3. The dihedral beam splitter 3 reflects the beam to the focusing lens 402 in the line focusing unit 4. The focusing lens 402 focuses the multiple sub-beams, forming a high aspect ratio, uniformly distributed focusing line on the surface of the sample 5 to be tested, thus exciting the sample 5 and generating a Rayleigh beam with the same frequency as the laser beam. Scattered light and Raman scattered light with changing frequency, Rayleigh scattered light and Raman scattered light return along the original optical path through the focusing lens 402 in the line focusing unit 4 to become collimated light, and then through the two-way beam splitter 3 to reach the Raman spectral signal separation and acquisition unit 6. Rayleigh scattered light is filtered out by a 532nm high-pass filter 601. Raman scattered light is eliminated by an achromatic triplet lens 602 to eliminate aberrations such as chromatic aberration and spherical aberration and is collected into the spectrometer 7. In the spectrometer 7, a Raman spectral electrical signal is formed and transmitted to the computer control unit 8. The computer control unit 8 changes the parameters of the spectrometer control software, acquires the total Raman spectrum of a single line laser beam spot or multiple Raman spot data, and draws the Raman spectrum based on the Raman scattering data. After processing the Raman spectrum, the Raman spectrum of the sample 5 can be drawn.

[0092] Some embodiments of the present invention further provide a method for acquiring planetary laser Raman spectroscopy in line focusing mode, as shown in the appendix. Figure 5 As shown, it includes the following steps.

[0093] S1: Start the computer control unit 8 and the laser emitting unit 1. Adjust the laser emission parameters of the laser emitting unit 1 through the computer control unit 8. The laser emitting unit 1 outputs a collimated laser beam. The laser beam passes through the reflector 104 to change the optical path and exit direction and enters the beam expander unit 2.

[0094] S2: Adjust beam expander unit 2 to change its magnification and focal length so that the laser beam is incident on line focusing unit 4 with a suitable spot size.

[0095] In some embodiments of the present invention, the method for adjusting the beam expander unit 2 in step S2 includes:

[0096] Adjust the relative distance between the negative lens 201 and the positive lens 202 in the beam expander unit 2 to change the magnification and focal length of the beam expander unit 2.

[0097] S3: Place the sample 5 to be tested at the focusing position of the focusing lens 402 in the line focusing unit 4; the line focusing unit 4 shapes the laser beam into a focused linear spot with a high aspect ratio and uniform light intensity distribution to irradiate the sample 5 to be tested, and excites Rayleigh scattering light signal and Raman scattering light signal of the sample 5 to be tested within the spot area.

[0098] S4: The Rayleigh scattering light signal and Raman scattering light signal of the sample 5 to be tested return along the original optical path, and pass through the focusing lens 402 of the line focusing unit 4 and the two-way beam splitter 3 in sequence before entering the Raman spectral signal separation and acquisition unit 6.

[0099] After filtering out Rayleigh scattering signals and eliminating aberrations such as chromatic aberration and spherical aberration, the Raman spectral signal separation and acquisition unit 6 focuses the Raman scattering light and couples it to the spectrometer unit 7, which is placed at the focal position of the achromatic triplet lens 602 in the Raman spectral signal separation and acquisition unit 6.

[0100] S5: The computer control unit 8 adjusts the spectral acquisition parameters of the spectrometer 7 unit and the operating parameters of the area array CCD detector in the spectrometer 7 to acquire single-line Raman scattered light spot corresponding to a single total Raman spectrum or multiple Raman point spectrum data, and plots the corresponding Raman spectrum based on the acquired single total Raman spectrum or multiple Raman point spectrum data.

[0101] In some embodiments of the present invention, the following steps are also included:

[0102] n test points are divided on the surface of the sample 5 to be tested;

[0103] The computer control unit 8 adjusts the operating parameters of the area array CCD detector in the spectrometer 7. The area array CCD detector divides a single line spot into n point spots based on n test points on the surface of the sample 5 to be tested. Based on the n point spectra after division, the data of all the Raman point spectra collected are merged to output the n Raman point spectrum data corresponding to the n point spots.

[0104] Finally, it should be noted that the various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0105] The above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them; although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications can still be made to the specific implementation of the present invention or equivalent substitutions can be made to some technical features without departing from the spirit of the technical solutions of the present invention, and all such modifications and substitutions should be covered within the scope of the technical solutions claimed in the present invention.

Claims

1. A planetary laser Raman spectroscopy acquisition device with line focusing mode, characterized in that, include: Laser emitting unit: used to output a laser beam and adjust the power of the laser beam; Beam expander unit: disposed in the emission direction of the laser emitting unit, used to keep the laser beam collimated and change the diameter of the laser beam; Line focusing unit: disposed along the optical path of the laser beam in the output direction of the beam expander unit, the line focusing unit includes a cylindrical mirror array and a focusing lens, used to shape the laser beam into an ideal focal line with a high aspect ratio and uniform light intensity distribution; The cylindrical lens array includes multiple elongated cylindrical unit lenses with the same length, width, and radius of curvature. The multiple elongated cylindrical unit lenses are arranged in parallel. Each cylindrical unit lens is combined with a focusing lens to focus the laser beam incident on the cylindrical unit lens into a linear spot. The focal line light intensity produced by adjacent cylindrical unit lenses is opposite and they compensate and superimpose with each other. The focal lines produced by all cylindrical unit lenses are superimposed to form an ideal focal line with uniform light intensity distribution. The focal length of the ideal focal line It conforms to the following formula: ； in, The diameter of the incident laser spot is denoted as . The focal length of the focusing lens. This represents the number of unit cylindrical lenses. The focal length of the unit cylindrical lens; The sample to be tested is positioned at the focal point of the focusing lens. The laser beam passes sequentially through the cylindrical mirror array and the focusing lens before illuminating the sample to be tested, exciting linear Raman scattering on the surface of the sample. The Raman scattering is reflected back to the focusing lens, which is also used to collimate the Raman scattering. A two-way beam splitter is disposed between the cylindrical mirror array and the focusing lens along the optical path of the laser beam. It is used to reflect the laser beam passing through the cylindrical mirror array to the focusing lens and transmit the Raman scattered light excited by the laser beam on the surface of the sample to be tested. Raman spectroscopy signal separation and acquisition unit: The Raman scattered light is set along the transmission direction of the two-dimensional beam splitter along the optical path of the Raman scattered light after collimation by the focusing lens, and is used to focus the Raman scattered light and eliminate the Rayleigh scattered light excited by the laser beam on the surface of the sample to be tested; Spectrometer: Located at the focal point of the Raman scattered light focused by the Raman spectral signal separation and acquisition unit, it is used to receive the focused Raman scattered light and convert the Raman scattered light signal into a Raman scattered electrical signal; the spectrometer is equipped with an area array CCD detector, and the linear Raman scattered light signal focused at the front end of the spectrometer slit corresponds one-to-one with each row of pixels of the area array CCD detector, so as to realize the output of multiple point spectra on a single linear Raman scattered light spot; Computer control unit: electrically connected to the laser emitting unit, used to adjust the laser emission parameters of the laser emitting unit; electrically connected to the spectrometer, used to adjust the spectral acquisition parameters of the spectrometer and the operating parameters of the area array CCD detector; also used to acquire the Raman scattering electrical signal output by the spectrometer, and based on the acquired Raman scattering electrical signal, to plot a single Raman total spectrum or multiple Raman point spectra excited by a single linear laser beam spot on the surface of the sample under test.

2. The planetary laser Raman spectroscopy acquisition device in line-focusing mode according to claim 1, characterized in that, The Raman spectral signal separation and acquisition unit includes a high-pass filter and an achromatic triplet lens arranged sequentially along the optical path of the Raman scattered light transmitted through the two-way beam splitter. The high-pass filter is used to filter Rayleigh scattered light excited by the laser beam on the surface of the sample to be tested. The achromatic triplet lens is used to eliminate the aberrations of the Raman scattered light transmitted through the high-pass filter and to focus the Raman scattered light transmitted through the high-pass filter and couple it into the spectrometer.

3. The planetary laser Raman spectroscopy acquisition device in line-focusing mode according to claim 1, characterized in that, The spectrometer collimates the focused Raman scattered light into parallel light, and disperses light of different wavelengths into different angles through a grating, focusing it onto different positions of the area array CCD detector to form multiple image points; The area array CCD detector measures the light intensity of each wavelength image point and converts the Raman scattered light signal into a Raman scattered electrical signal for output; the Raman scattered electrical signal includes the total Raman spectrum data of a single line laser beam spot excited by the area array CCD detector under different operating parameters, or the spectrum data of multiple Raman points excited by a single line laser spot.

4. The planetary laser Raman spectroscopy acquisition device in line-focusing mode according to claim 1 or 3, characterized in that, The computer control unit includes a laser adjustment module, a spectrometer adjustment module, and a Raman spectrum plotting module; The laser adjustment module is used to adjust the laser emission parameters of the adjustable laser emission unit; The spectrometer adjustment module is used to adjust the spectral acquisition parameters of the spectrometer and the operating parameters of the area array CCD detector. The Raman spectroscopy plotting module is used to acquire the Raman scattering electrical signal output by the spectrometer, and plot the corresponding Raman spectrum based on the single total Raman spectral data or multiple Raman point spectral data output by the spectrometer.

5. The planetary laser Raman spectroscopy acquisition device in line-focusing mode according to claim 1, characterized in that, The laser emitting unit includes a laser, an optical isolator, a laser attenuator, and a reflector; the optical isolator is disposed at the output port of the laser to prevent reflected light from returning to the laser; the laser attenuator is disposed in the output optical path of the optical isolator to change the energy of the laser beam; and the reflector is disposed in the output optical path of the laser attenuator to change the propagation direction of the laser beam.

6. The planetary laser Raman spectroscopy acquisition device in line-focusing mode according to claim 1, characterized in that, The beam expander unit includes a negative lens and a positive lens arranged sequentially along the optical path of the laser beam. By changing the relative distance between the negative lens and the positive lens, the magnification and focal length of the beam expander unit can be adjusted.

7. A method for acquiring planetary laser Raman spectra in line-focusing mode, using the planetary laser Raman spectra acquisition device in line-focusing mode as described in claims 1-6, characterized in that, Includes the following steps: S1: Start the computer control unit and the laser emitting unit. Adjust the laser emitting parameters of the laser emitting unit through the computer control unit. The laser emitting unit outputs a collimated laser beam, which enters the beam expander unit after being emitted. S2: Adjust the beam expander unit to change the magnification and focal length of the beam expander unit so that the laser beam is incident on the line focusing unit with a suitable spot size; S3: Place the sample to be tested at the focusing position of the focusing lens in the line focusing unit; the line focusing unit shapes the laser beam into a focused linear spot with a high aspect ratio and uniform light intensity distribution to illuminate the sample to be tested, and excites Rayleigh scattering light signal and Raman scattering light signal of the sample to be tested within the spot area. S4: The Rayleigh scattering and Raman scattering signals of the sample to be tested return along the original optical path, pass through the focusing lens of the line focusing unit and the two-dimensional beam splitter in sequence, and then enter the Raman spectral signal separation and acquisition unit; the Raman spectral signal separation and acquisition unit filters out the Rayleigh scattering signal and eliminates the aberration of the Raman scattering signal, then focuses the Raman scattering signal and couples it into the spectrometer. S5: Adjust the spectral acquisition parameters of the spectrometer unit and the operating parameters of the area array CCD detector in the spectrometer through the computer control unit to acquire single Raman total spectral data or multiple Raman point spectral data corresponding to a single linear Raman scattering light spot, and draw the corresponding Raman spectrum based on the acquired single Raman total spectral data or multiple Raman point spectral data.

8. The planetary laser Raman spectroscopy acquisition method in line-focusing mode according to claim 7, characterized in that, It also includes the following steps: Divide the surface of the sample to be tested into n test points; The computer control unit adjusts the operating parameters of the area CCD detector in the spectrometer. The area CCD detector divides a single line spot into n point spots based on n test points on the surface of the sample to be tested. Based on the n point spectra after division, the data of all the Raman point spectra collected are merged to output the n Raman point spectrum data corresponding to the n point spots.

9. The planetary laser Raman spectroscopy acquisition method in line-focusing mode according to claim 7, characterized in that, The method for adjusting the beam expander unit in step S2 includes: Adjust the relative distance between the negative lens and the positive lens in the beam expander unit to change the magnification and focal length of the beam expander unit.

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