Planetary laser spectroscopy acquisition device and method combining remote ultraviolet raman-fluorescence technology

Abstract

The application discloses a kind of planet laser spectroscopy acquisition device and method combined with remote ultraviolet Raman-fluorescence technology, and it is related to deep space exploration spectral measurement technical field.The device includes ultraviolet laser emission unit, beam expander unit, dichroic beam splitter, cassegrain telescope unit, signal separation and acquisition unit, Raman spectrometer, fluorescence spectrometer and computer control unit.Laser is projected to remote target by cassegrain telescope after beam expansion and dichroic beam splitter, and the Raman and fluorescence signals excited are received by the same telescope, then after filtering out Rayleigh scattering light, they are collected by optical fiber into corresponding spectrometer.The application can realize the integrated collection of ultraviolet Raman and fluorescence spectrum of remote, non-contact planetary surface material, and provide efficient optical detection means for mineral composition identification, organic matter and potential life marker detection.

Description

Technical Field

[0001] This invention belongs to the field of deep space exploration spectral measurement technology, and in particular relates to a planetary laser spectral acquisition device and method that combines long-range ultraviolet Raman-fluorescence technology. Background Technology

[0002] Obtaining precise mineral composition and potential organic information from the surface materials of planets such as Mars is crucial for revealing their geological evolution history and assessing their habitability. Ultraviolet Raman spectroscopy, as a non-contact, non-destructive "fingerprint" identification method, can not only accurately identify mineral types and structures through molecular vibrational characteristics, but also, due to its shorter excitation wavelength, higher photon energy, and resonance enhancement effect on the Raman peaks of many minerals and organics, it can obtain stronger Raman signals and higher sensitivity at long distances, making it a highly promising in-situ planetary detection technology. Meanwhile, ultraviolet fluorescence spectroscopy is extremely sensitive to organic molecules and biomarkers. Its ultraviolet excitation band can effectively excite the characteristic fluorescence of various organics and potential biomolecules, providing unique and direct spectroscopic evidence for the search for traces of extraterrestrial life. Remote ultraviolet Raman-fluorescence technology can efficiently identify and analyze the "molecular fingerprint" spectral information of various key minerals and organics in rock and soil samples from the surface of planets such as Mars in situ and at micro-areas, assessing the samples' potential for life traces and geological background, and providing crucial predictions for the scientific value of returned samples. Integrating ultraviolet Raman and fluorescence detection capabilities into a single instrument is an important tool for identifying the mineral composition, rock types, and organic matter on the Martian surface. It has significant scientific value, especially for detecting traces of life on Mars and studying altered minerals, and has important application value and potential in the field of deep space exploration.

[0003] Currently, most spectroscopic payloads used for detecting the composition of materials on the surfaces of planets such as Mars are single-function devices. While Raman spectrometers can accurately identify minerals, their ability to directly detect complex organic matter, especially life-related substances, is limited; and single fluorescence detection devices often lack precise mineral identification capabilities. In actual exploration missions, obtaining mineralogical and organic information for the same area often requires the coordinated operation of multiple instruments, which not only increases mission complexity, weight, and power consumption, but also prolongs the single-point detection time. Summary of the Invention

[0004] In view of this, the present invention aims to provide a planetary laser spectral acquisition device and method that combines remote ultraviolet Raman-fluorescence technology, so as to achieve integrated, high-efficiency, and high signal-to-noise ratio in-situ detection of mineral components, potential organic matter, and life markers on the surface of planets such as Mars.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: A planetary laser spectral acquisition device combining long-range ultraviolet Raman-fluorescence technology includes: The ultraviolet laser emitting unit is used to output an ultraviolet laser beam and adjust the power and frequency of the laser beam. The beam expander unit is set in the output optical path of the ultraviolet laser emitting unit and is used to expand and collimate the ultraviolet laser beam. A dichroic beam splitter is positioned along the optical path in the output direction of the beam expander unit to reflect the shaped ultraviolet laser beam to the Cassegrain telescope unit and transmit the returned signal light. The Cassegrain telescope unit is used to project an ultraviolet laser beam onto a distant sample, collect the excited Raman scattered light and fluorescence signal, and return the received signal to the dichroic beam splitter. The signal separation and acquisition unit is set along the optical path in the transmission direction of the dichroic beam splitter to filter out Rayleigh scattered light in the returned signal and to focus and couple Raman and fluorescence signals to the optical fiber. The fiber optic switching unit includes: an ultraviolet array fiber bundle, whose input end receives a focused light spot from the output end of the signal separation and acquisition unit, and whose output end converts the light spot into a linear light signal to match the entrance slit of the Raman spectrometer; and an ultraviolet fiber for directly coupling the fluorescence signal to the fluorescence spectrometer; the output ends of the ultraviolet array fiber bundle and the ultraviolet fiber are respectively connected to the corresponding spectrometers, or selectively connected to the currently operating spectrometer through a switching mechanism; The Raman spectrometer is time-gated and equipped with an ICMOS detector for acquiring ultraviolet Raman spectra. A fluorescence spectrometer, equipped with a CCD detector, is used to acquire ultraviolet fluorescence spectra; The computer control unit is electrically connected to the ultraviolet laser emitting unit, Raman spectrometer, and fluorescence spectrometer. It is used to set laser parameters, select the working spectrometer and set its acquisition parameters, as well as acquire and process spectral data and draw ultraviolet Raman and fluorescence spectra.

[0006] Furthermore, the signal separation and acquisition unit includes a high-pass filter and a focusing coupling lens arranged sequentially along the optical path. The high-pass filter is used to filter out Rayleigh scattering light in the returned signal, and the focusing coupling lens is used to focus and couple the filtered Raman signal and fluorescence signal to the input end of the optical fiber bundle.

[0007] Furthermore, the input end of the ultraviolet array fiber bundle is arranged in a spot-like pattern to receive the focused light spot, and the output end is arranged in a linear pattern to convert the point focusing signal into a line signal that matches the slit shape of the Raman spectrometer, thereby improving the signal coupling efficiency.

[0008] Furthermore, the Raman spectrometer includes an entrance slit, a grating, an ICMOS detector, and a control circuit. The operating timing of the Raman spectrometer is synchronized with the laser pulse emission timing of the ultraviolet laser emitting unit, and is used to start acquisition within the time window when the Raman signal arrives, so as to suppress fluorescence background and stray light.

[0009] Furthermore, the computer control unit includes a spectrometer adjustment module and a data processing module. The spectrometer adjustment module is used to select the currently operating spectrometer and set acquisition parameters for the selected spectrometer. Specifically, it sets time gating parameters, gain parameters, integration time, and accumulation count for the Raman spectrometer, and sets integration time and accumulation count for the fluorescence spectrometer. The data processing module is used to receive, process, and display spectral data from the spectrometer.

[0010] Furthermore, the ultraviolet laser emitting unit includes an ultraviolet pulsed laser and a reflector group. The reflector group is disposed in the output optical path of the ultraviolet pulsed laser and is used to guide the laser beam to the beam expander unit.

[0011] Furthermore, the beam expander unit is an adjustable magnification beam expander, which changes the diameter and divergence angle of the output laser beam by adjusting the spacing between its internal lenses to adapt to long-distance detection targets.

[0012] Furthermore, the surfaces of the reflector group in the ultraviolet laser emitting unit, the optical mirror of the Cassegrain telescope unit, and the focusing optical lens in the signal separation and acquisition unit are all coated with a film layer to enhance the optical performance in the ultraviolet band.

[0013] A method for planetary laser spectral acquisition combining long-range ultraviolet Raman-fluorescence technology includes the following steps: S1. Start the computer control unit and the ultraviolet laser emission unit, adjust the laser parameters, and after the laser is collimated and shaped by the beam expander unit, it is reflected by the dichroic beam splitter to the Cassegrain telescope unit; S2. The Cassegrain telescope unit focuses an ultraviolet laser beam onto a distant sample to excite it to generate Raman scattered light and fluorescence signals; S3. The excitation signal is collected and returned by the same Cassegrain telescope unit, and after passing through the dichroic beam splitter, it enters the signal separation and acquisition unit to filter out Rayleigh scattered light; S4. According to the detection requirements, the ultraviolet fiber bundle or ultraviolet fiber output by the signal separation and acquisition unit is switched to a time-gated Raman spectrometer or a fluorescence spectrometer. S5. Set the parameters of the selected spectrometer through the computer control unit, collect spectral data, and process and plot the corresponding ultraviolet Raman spectrum or fluorescence spectrum.

[0014] Furthermore, in step S5, the computer control unit automatically calls the corresponding preset parameter template to set the acquisition parameters according to the type of the selected spectrometer. Specifically, for the time-gated Raman spectrometer, a first parameter template containing time gating width, delay, and gain is called, and for the fluorescence spectrometer, a second parameter template containing integration time and accumulation count is called.

[0015] Compared with the prior art, the present invention has the following significant effects: 1. This invention innovatively integrates ultraviolet Raman spectroscopy and ultraviolet fluorescence spectroscopy into a single system through a shared optical path and switchable detection channels. Due to its shorter wavelength, ultraviolet lasers exhibit a significantly increased Raman scattering cross-section and a resonance enhancement effect on the Raman peaks of various minerals and organic compounds. This allows for the acquisition of high signal-to-noise ratio Raman signals even under long-distance detection conditions on planets such as Mars, greatly improving the sensitivity and reliability of mineral identification. Simultaneously, the ultraviolet fluorescence detection channel is extremely sensitive to organic compounds and potential biomarkers. The integrated design of this invention enables the acquisition of mineral "fingerprints" and organic information of a target in a single aiming motion, solving the problem of relying on multiple instruments and multiple alignments for comprehensive characterization in existing technologies, significantly improving detection efficiency and scientific returns.

[0016] 2. This invention employs an "ultraviolet array fiber bundle" to couple Raman signals, efficiently converting the received point-focused signal into a line signal matching the slit shape of the time-gated Raman spectrometer, significantly improving signal coupling efficiency. Combined with the use of an ICMOS detector in the spectrometer, its gating timing is synchronized with the laser pulse, effectively suppressing strong sunlight background, sample fluorescence, and cosmic ray noise in long-distance detection, thereby extracting weak Raman characteristic peaks even in complex planetary environments. Key optical components in the signal optical path are coated with ultraviolet anti-reflection or high-reflection coatings, further ensuring optical transmission efficiency in the ultraviolet band.

[0017] 3. The device and method provided by this invention achieve two highly complementary detection functions (mineral identification and organic matter detection) through a single hardware system, avoiding the significant increase in weight, power consumption, and cost associated with carrying two independent instruments. Switchable fiber optic interfaces and automated parameter template management simplify operation and enable rapid mode switching. This not only greatly saves valuable resources for deep space exploration missions and reduces the time required for comprehensive single-point detection, but also provides a reliable, flexible, and highly engineering-feasible new technical means for large-scale, high-efficiency mineral surveys and searches for traces of life on the surfaces of planets such as Mars. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the arrangement of the planetary laser spectral acquisition device combining remote ultraviolet Raman-fluorescence technology of the present invention; Figure 2 This is a schematic diagram of the planetary laser spectral acquisition device combining remote ultraviolet Raman-fluorescence technology of the present invention; Figure 3 This is a schematic diagram showing the coupling between the ultraviolet array fiber bundle of the signal separation and acquisition unit and the slit shape of the time-gated Raman spectrometer in the device provided by the present invention. Figure 4 Signal collection optical path diagram of the planetary laser spectral acquisition device combining remote ultraviolet Raman-fluorescence technology provided by the present invention; Figure 5 This invention provides a light spot energy distribution diagram for collecting light from the front end of the optical fiber. Figure 6 The timing diagram shows the principle of Raman signal acquisition using a time-gated Raman spectrometer. Figure 7 The flowchart illustrates the planetary laser spectral acquisition method combining remote ultraviolet Raman-fluorescence technology provided by this invention.

[0019] In the diagram: 1. Ultraviolet laser emitting unit; 2. Beam expander unit, 201, concave lens, 202, convex lens; 3. Dichroic beam splitter; 4. Cassegrain telescope unit, 401, secondary mirror, 402, primary mirror; 5. Long-distance sample to be tested; 6. Signal separation and acquisition unit, 601. High-pass filter, 602. Focusing coupling lens, 603. Ultraviolet array fiber bundle, 604. Ultraviolet fiber; 7. Spectrometer, 701. Time-gated Raman spectrometer; 702. Fluorescence spectrometer; 8. Computer control unit. Detailed Implementation

[0020] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

[0021] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "horizontal," "inner," "outer," and "one side," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, unless otherwise explicitly specified and limited, the terms "installed," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0022] Example 1

[0023] like Figure 1-6 As shown in the figure, this embodiment discloses a planetary laser spectral acquisition device combining remote ultraviolet Raman-fluorescence technology. The acquisition device includes an ultraviolet laser emission unit 1, a beam expander unit 2, a dichroic beam splitter 3, a Cassegrain telescope unit 4, a signal separation and acquisition unit 6, a Raman and fluorescence spectrometer 7, and a computer control unit 8.

[0024] The ultraviolet laser emitting unit 1 is equipped with an ultraviolet pulsed laser for outputting an ultraviolet laser beam, and the power and frequency of the laser beam can be adjusted. In this embodiment, the pulsed laser beam emitted by the ultraviolet laser emitting unit 1 has a wavelength of 266.2 nm, a frequency of 1 kHz, a single pulse energy of 100 μJ (adjustable), and a pulse width of 5.5 ns. This ultraviolet band can effectively excite Raman scattering and induce characteristic fluorescence in organic matter. At the same time, the short wavelength characteristic can increase the Raman scattering cross section and may produce a resonance enhancement effect on specific minerals, thereby physically improving the original signal intensity and laying the foundation for subsequent long-distance detection.

[0025] The beam expander unit 2 is disposed in the output optical path of the ultraviolet laser emitting unit 1 and is used to expand and collimate the ultraviolet laser beam to adapt to the spot size required for long-distance projection. In this embodiment, the beam expander unit 2 is an adjustable magnification beam expander with a magnification of up to 2.5 times, and the optical surface of the lens is coated with an ultraviolet anti-reflection film.

[0026] The dichroic beam splitter 3 is positioned along the optical path in the exit direction of the beam expander unit 2. The dichroic beam splitter 3 is placed at 20° to the collecting optical path to efficiently reflect the 266.2nm ultraviolet excitation beam to the Cassegrain telescope unit 4 and efficiently transmit the return signal light (including Raman scattered light and fluorescence) with a wavelength greater than 270nm.

[0027] The Cassegrain telescope unit 4 is located in the reflected light path of the dichroic beam splitter 3 and consists of a primary mirror 402 and a secondary mirror 401. This telescope unit 4 serves as a common optical path component for both laser emission and signal reception. On the one hand, it focuses and projects the incident collimated ultraviolet laser beam onto the distant sample 5 to be tested. On the other hand, it receives the excited Raman scattered light and fluorescence signal returned from the sample 5, collimates it, and returns it along the original path.

[0028] The signal separation and acquisition unit 6 is located in the transmission optical path of the dichroic beam splitter 3 and is used to process the returned mixed optical signal. It first filters out strong Rayleigh scattering light through a high-pass filter 601, and then the focusing coupling lens 602 efficiently focuses the signal light (Raman and fluorescence) to the fiber input end. This focusing coupling lens is optimized to achieve high optical efficiency in the ultraviolet band, and its surface is coated with a corresponding anti-reflection film.

[0029] The optical fiber output from the signal separation and acquisition unit 6 can be selectively connected to the entrance slit of the time-gated Raman spectrometer 701 or the fluorescence spectrometer 702, depending on the detection target, to achieve time-division spectral acquisition.

[0030] The time-gated Raman spectrometer 701 is used to receive and process Raman scattering signals. Its core is an ICMOS detector, whose operating timing is strictly synchronized with the ultraviolet laser pulses via a computer control unit 8. By setting a gate time window with a nanosecond width (optimized to 20 nanoseconds in this embodiment, with a delay time of 59 nanoseconds), the detector is precisely controlled to start acquisition within the arrival time of Raman photons. This parameter combination maximizes the collection of Raman scattering signals while effectively blocking most of the long-lived fluorescence background, sunlight background, and cosmic ray noise, thus significantly improving the signal-to-noise ratio of the Raman spectrum at the hardware level. Specifically, this time-gated technology can suppress the main fluorescence background noise by one to two orders of magnitude, improving the signal-to-noise ratio of the Raman spectrum by more than 10 times compared to the non-gated continuous acquisition mode, thus providing crucial assurance for the detection of weak Raman characteristic peaks in complex backgrounds. Subsequently, the Raman scattered light from the ultraviolet fiber bundle is dispersed by the grating in the spectrometer, and light of different wavelengths is imaged on different pixel columns of the ICMOS area array detector and converted into corresponding electrical signals.

[0031] The fluorescence spectrometer 702 is used to receive and process fluorescence signals. It is equipped with a high-sensitivity, wide-spectral-range CCD detector, suitable for acquiring fluorescence emission signals with broad spectral bands. After the fluorescence signal from the sample target is coupled into the spectrometer, it undergoes grating dispersion, and fluorescence signals of different wavelengths are separated and imaged onto different pixel columns of the CCD detector, subsequently being converted into electrical signals.

[0032] The computer control unit 8 is connected to the time-gated Raman spectrometer 701 and the fluorescence spectrometer 702 via data cables, forming a unified control and data processing core. The ultraviolet laser emission unit 1 is connected to the time-gated Raman spectrometer 701 via a coaxial cable to transmit precise synchronization trigger signals, ensuring high-precision timing synchronization between the laser pulse and the detector gating. The main functional modules of the computer control unit 8 include: Spectrometer adjustment module: Used to select the currently active spectrometer channel (Raman or fluorescence) and automatically call the preset optimized parameter set for the selected spectrometer. For the time-gated Raman spectrometer 701, key parameters include time gating width, delay parameter, integration time, and number of accumulations; for the fluorescence spectrometer 702, key parameters include integration time and number of accumulations.

[0033] Data processing module: Used to acquire and interpret electrical signals from the spectrometer in real time, perform dark noise subtraction, spectral calibration, baseline correction and other processing on the raw spectral data, and finally draw and display the corresponding high-quality ultraviolet Raman spectrum or fluorescence spectrum to complete the analysis of mineral or organic information of samples from a distance.

[0034] It should be noted that, in this exemplary embodiment, the pulsed laser used in the ultraviolet laser emitting unit 1 has a center wavelength of 266.2 nm, and the optical characteristics (such as transmittance, reflectance, cutoff wavelength, etc.) of key optical components such as the beam expander unit 2, the dichroic beam splitter 3, and the signal separation and acquisition unit 6 in the device have been optimized for this ultraviolet excitation band in order to achieve the best Raman and fluorescence joint detection performance.

[0035] In a preferred embodiment of the present invention, the beam expander unit 2 includes a concave lens 201 and a convex lens 202 arranged sequentially along the optical path of the ultraviolet laser beam, forming a tunable Galilean beam expander system. Since laser light inherently diverges during transmission, the magnification and effective focal length of the beam expander unit 2 can be changed by adjusting the relative distance between the concave lens 201 and the convex lens 202, thereby outputting a laser beam with a suitable spot diameter and excellent collimation for different long-distance detection needs. Specifically, the laser beam emitted by the ultraviolet laser emitting unit 1 first enters the concave lens 201, where its divergence effect expands the beam diameter; subsequently, the divergent beam is received by the convex lens 202 and re-collimated. By optimizing the spacing between the two lenses, the system can achieve flexible adjustment of the beam diameter while ensuring high spatial collimation of the output beam, laying the foundation for subsequent long-distance efficient transmission and precise focusing.

[0036] In a preferred embodiment of the present invention, to achieve remote detection and form a high-quality detection spot, the Cassegrain telescope unit 4 employs a reflective optical design. It includes a convex secondary mirror 401 and a concave primary mirror 402. This combination provides a large usable field of view. The collimated laser beam is first reflected by the secondary mirror 401 and redirected to the primary mirror 402, then reflected again by the primary mirror 402 and projected onto the distant sample 5 to be tested. This process focuses the laser energy onto the target area. Simultaneously, the Raman and fluorescence signals excited from the sample return along the original path, are collected by the primary mirror 402 and reflected back to the secondary mirror 401, and finally collimated by the secondary mirror 401 before being output. This system can form a concentrated, small-sized detection spot at the sample.

[0037] In a preferred embodiment of the present invention, the signal separation and acquisition unit 6 includes a high-pass filter 601 and a focusing coupling lens 602 arranged sequentially. The high-pass filter 601 is used to efficiently filter the short-wavelength Rayleigh scattering light excited by the laser beam on the surface of the sample 5 under test, thereby significantly improving the signal-to-noise ratio. Figure 4 Signal collection optical path diagram of the planetary laser spectral acquisition device Figure 5 The energy distribution diagram of the light spot visually shows the shape of the focused light spot before entering the optical fiber, and it can be seen that the focused light spot is small and has high energy density.

[0038] In a preferred embodiment of the present invention, the time-gated Raman spectrometer 701 integrates an area-array ICMOS detector, which possesses excellent time-controlled acquisition capabilities and high sensitivity. To address the problem of strong fluorescence background interference that may occur in the sample 5 under ultraviolet laser excitation, this embodiment utilizes the significant time delay difference between Raman scattering and fluorescence emission on the nanosecond scale, employing time-gated sequence acquisition technology. Figure 6 As shown, after laser pulse excitation, the Raman signal reaches its peak rapidly first, while the fluorescence signal exhibits a significant delay and slow decay. By precisely setting the nanosecond-level time-gated window of the time-gated Raman spectrometer 701, this window is strictly limited to a very short time after the laser pulse, when the fluorescence signal is not yet fully excited or is at an extremely low level. This allows only the Raman scattered light signal to pass through and be efficiently recorded, while the delayed strong fluorescence signal is effectively blocked from entering the gate.

[0039] As a preferred embodiment of the present invention, the computer control unit 8 is capable of storing the acquired Raman and fluorescence spectral data, and the computer control unit 8 also includes a human-computer interaction screen to adjust the parameters of the time-gated Raman spectrometer 701 and the fluorescence spectrometer 702, and to view the acquired spectral data and plotted spectral graphs in real time.

[0040] The specific workflow of the planetary laser spectral acquisition device combining remote ultraviolet Raman-fluorescence technology provided by this invention is as follows: The ultraviolet pulse laser of the ultraviolet laser emission unit 1 is activated, outputting a pulsed laser beam with a wavelength of 266.2 nm; the laser beam enters the adjustable magnification beam expander unit 2 for beam expansion and collimation shaping, forming a collimated beam suitable for long-distance transmission; this beam is reflected by the dichroic beam splitter 3 to the Cassegrain telescope unit 4, and after two reflections by the secondary mirror 401 and the primary mirror 402, it is projected onto the distant sample 5 to be tested; the laser energy is focused on the sample surface, generating Raman scattered light, fluorescence signal, and Rayleigh scattered light. The generated light signal is collected by the same Cassegrain telescope unit 4 and returns along the original path, passing through the dichroic beam splitter 3 and entering the signal separation and acquisition unit 6. First, the Rayleigh scattered light is filtered out by the high-pass filter 601, and then converged and coupled to the optical fiber by the focusing coupling lens 602. Based on the scientific objectives of this detection, the connection to either the ultraviolet fiber bundle 603 or the ultraviolet fiber 604 is switched: when Raman signal detection is performed, it is connected to the time-gated Raman spectrometer 701, and the computer control unit 8 synchronizes the laser pulse with the timing of the time-gated Raman spectrometer 701, setting a nanosecond-level gating window to suppress fluorescence background; when fluorescence signal detection is performed, it is connected to the fluorescence spectrometer 702. The selected spectrometer disperses the light signal and converts it into an electrical signal by the detector, which is then transmitted to the computer control unit 8 for processing, calibration, and imaging, ultimately plotting and displaying the ultraviolet Raman spectrum or fluorescence spectrum of the sample.

[0041] Example 2

[0042] Based on Example 1, this invention further provides a planetary laser spectral acquisition method combining remote ultraviolet Raman-fluorescence technology, such as... Figure 7 As shown, it includes the following steps: S1. Start the computer control unit 8 and the ultraviolet laser emission unit 1, and set the acquisition parameters through the computer control unit 8; the ultraviolet laser beam enters the beam expander unit 2 for collimation and shaping to form a light spot suitable for long-distance projection, and is then reflected by the dichroic beam splitter 3 to the Cassegrain telescope unit 4.

[0043] S2. The Cassegrain telescope unit 4 (through its internal secondary mirror 401 and primary mirror 402) focuses and projects an ultraviolet laser beam onto the distant sample 5 to be tested, exciting the sample 5 to generate Raman scattered light, fluorescence signal and Rayleigh scattered light.

[0044] S3. The excited signal is collected by the same Cassegrain telescope unit 4 and returns along the original path. After passing through the dichroic beam splitter 3, it enters the signal separation and acquisition unit 6, where the Rayleigh scattered light is filtered out by the high-pass filter 601.

[0045] S4. According to the detection requirements, the ultraviolet array fiber bundle 603 or ultraviolet fiber 604 output by the signal separation and acquisition unit 6 is switched to the time-gated Raman spectrometer 701 or the fluorescence spectrometer 702.

[0046] S5. The computer control unit 8 calls the set parameters for the selected spectrometer (sets the time-gated Raman spectrometer 701 with time-gated parameters, integration time, etc., and sets the integration time and number of accumulations for the fluorescence spectrometer 702), collects spectral data, processes and plots the corresponding ultraviolet Raman spectrum or fluorescence spectrum.

[0047] While the specific embodiments of the present invention have been described above in conjunction with the accompanying drawings, this is not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art without creative effort based on the technical solutions of the present invention are still within the scope of protection of the present invention.

Claims

1. A planetary laser spectral acquisition device combining long-range ultraviolet Raman-fluorescence technology, characterized in that, include: The ultraviolet laser emitting unit is used to output an ultraviolet laser beam and adjust the power and frequency of the laser beam. The beam expander unit is set in the output optical path of the ultraviolet laser emitting unit and is used to expand and collimate the ultraviolet laser beam. A dichroic beam splitter is positioned along the optical path in the output direction of the beam expander unit to reflect the shaped ultraviolet laser beam to the Cassegrain telescope unit and transmit the returned signal light. The Cassegrain telescope unit is used to project an ultraviolet laser beam onto a distant sample, collect the excited Raman scattered light and fluorescence signal, and return the received signal to the dichroic beam splitter. The signal separation and acquisition unit is set along the optical path in the transmission direction of the dichroic beam splitter to filter out Rayleigh scattered light in the returned signal and to focus and couple Raman and fluorescence signals to the optical fiber. The fiber optic switching unit includes: an ultraviolet array fiber bundle, whose input end receives a focused light spot from the output end of the signal separation and acquisition unit, and whose output end converts the light spot into a linear light signal to match the entrance slit of the Raman spectrometer; and an ultraviolet fiber for directly coupling the fluorescence signal to the fluorescence spectrometer; the output ends of the ultraviolet array fiber bundle and the ultraviolet fiber are respectively connected to the corresponding spectrometers, or selectively connected to the currently operating spectrometer through a switching mechanism; The Raman spectrometer is time-gated and equipped with an ICMOS detector for acquiring ultraviolet Raman spectra. A fluorescence spectrometer, equipped with a CCD detector, is used to acquire ultraviolet fluorescence spectra; The computer control unit is electrically connected to the ultraviolet laser emitting unit, Raman spectrometer, and fluorescence spectrometer. It is used to set laser parameters, select the working spectrometer and set its acquisition parameters, as well as acquire and process spectral data and draw ultraviolet Raman and fluorescence spectra.

2. The planetary laser spectral acquisition device combining remote ultraviolet Raman-fluorescence technology according to claim 1, characterized in that, The signal separation and acquisition unit includes a high-pass filter and a focusing coupling lens arranged sequentially along the optical path. The high-pass filter is used to filter out Rayleigh scattering light in the returned signal, and the focusing coupling lens is used to focus and couple the filtered Raman signal and fluorescence signal to the input end of the optical fiber bundle.

3. The planetary laser spectral acquisition device combining remote ultraviolet Raman-fluorescence technology according to claim 1, characterized in that, The input end of the ultraviolet array fiber bundle is arranged in a spot-like pattern to receive the focused light spot, and the output end is arranged in a linear pattern to convert the point-focused signal into a line signal that matches the slit shape of the Raman spectrometer, thereby improving the signal coupling efficiency.

4. The planetary laser spectral acquisition device combining remote ultraviolet Raman-fluorescence technology according to claim 1, characterized in that, The Raman spectrometer includes an entrance slit, a grating, an ICMOS detector, and a control circuit. The operating timing of the Raman spectrometer is synchronized with the laser pulse emission timing of the ultraviolet laser emitting unit, and is used to start acquisition within the time window when the Raman signal arrives, so as to suppress fluorescence background and stray light.

5. The planetary laser spectral acquisition device combining remote ultraviolet Raman-fluorescence technology according to claim 1, characterized in that, The computer control unit includes a spectrometer adjustment module and a data processing module. The spectrometer adjustment module is used to select the currently operating spectrometer and set the acquisition parameters for the selected spectrometer. Specifically, it sets the time gating parameters, gain parameters, integration time, and number of accumulations for the Raman spectrometer, and sets the integration time and number of accumulations for the fluorescence spectrometer. The data processing module is used to receive, process, and display the spectral data from the spectrometer.

6. The planetary laser spectral acquisition device combining remote ultraviolet Raman-fluorescence technology according to claim 1, characterized in that, The ultraviolet laser emitting unit includes an ultraviolet pulsed laser and a reflector group. The reflector group is disposed in the output optical path of the ultraviolet pulsed laser and is used to guide the laser beam to the beam expander unit.

7. The planetary laser spectral acquisition device combining remote ultraviolet Raman-fluorescence technology according to claim 1, characterized in that, The beam expander unit is an adjustable magnification beam expander. By adjusting the spacing between its internal lenses, the diameter and divergence angle of the output laser beam can be changed to adapt to long-distance detection targets.

8. The planetary laser spectral acquisition device combining long-range ultraviolet Raman-fluorescence technology according to claim 1, characterized in that, The reflector group in the ultraviolet laser emitting unit, the optical mirror of the Cassegrain telescope unit, and the focusing optical lens in the signal separation and acquisition unit are all coated with a film layer to enhance the optical performance in the ultraviolet band.

9. A method for acquiring planetary laser spectra using a combination of long-range ultraviolet Raman-fluorescence technology, employing the acquisition device as described in any one of claims 1-8, characterized in that, Includes the following steps: S1. Start the computer control unit and the ultraviolet laser emission unit, adjust the laser parameters, and after the laser is collimated and shaped by the beam expander unit, it is reflected by the dichroic beam splitter to the Cassegrain telescope unit; S2. The Cassegrain telescope unit focuses an ultraviolet laser beam onto a distant sample to excite it to generate Raman scattered light and fluorescence signals; S3. The excitation signal is collected and returned by the same Cassegrain telescope unit, and after passing through the dichroic beam splitter, it enters the signal separation and acquisition unit to filter out Rayleigh scattered light; S4. According to the detection requirements, the ultraviolet fiber bundle or ultraviolet fiber output by the signal separation and acquisition unit is switched to a time-gated Raman spectrometer or a fluorescence spectrometer. S5. Set the parameters of the selected spectrometer through the computer control unit, collect spectral data, and process and plot the corresponding ultraviolet Raman spectrum or fluorescence spectrum.

10. A planetary laser spectral acquisition method combining long-range ultraviolet Raman-fluorescence technology according to claim 9, characterized in that, In step S5, the computer control unit automatically calls the corresponding preset parameter template to set the acquisition parameters according to the type of the selected spectrometer. Specifically, for the time-gated Raman spectrometer, a first parameter template containing time gating width, delay, and gain is called, and for the fluorescence spectrometer, a second parameter template containing integration time and accumulation count is called.

Images