Morphology, LIBS, Raman and fluorescence spectroscopy combined detection system and method

Abstract

This invention discloses a joint detection system and method for morphology, LIBS, Raman, and fluorescence spectroscopy, belonging to the field of spectral analysis and optical precision detection technology. The system adopts a common-aperture, common-optical-path architecture, integrating a three-in-one laser emission unit, an adaptive focusing unit, a two-dimensional scanning detection unit, a dual-period grating wide-band spectrometer unit, and an on-orbit fully automatic self-calibration unit. Through coaxial point excitation with three-band lasers at 266, 532, and 1064 nm, it simultaneously and time-divisionally acquires LIBS, ultraviolet Raman, and fluorescence spectra, as well as microscopic images. Coordinated adaptive focusing and local scanning enable efficient detection of complex targets, and fusion interpretation of multi-dimensional data on elemental composition, crystal phases, hydration characteristics, and organic matter. This invention significantly reduces equipment size, weight, and power consumption, effectively suppresses single-spectral matrix effects, improves detection accuracy and efficiency in complex terrains, and is suitable for lightweight deep-space payloads and rapid in-situ ground-based detection needs.

Description

Technical Field

[0001] This invention belongs to the field of spectral analysis and optical precision detection technology, specifically involving a joint detection system and method of morphology, LIBS, Raman and fluorescence spectroscopy. It is particularly suitable for in-situ comprehensive detection of rocks, soil, minerals, organic matter and hydrated components on the surface of celestial bodies in lunar and deep space exploration. At the same time, it can be extended to lightweight precision detection scenarios such as ground geological exploration, mineral detection and in-situ analysis of environmental pollutants. Background Technology

[0002] Laser-induced breakdown spectroscopy (LIBS), Raman spectroscopy, and fluorescence spectroscopy have become important tools for in-situ detection of inorganic and organic components in planetary geological samples due to their advantages such as no sample preparation required, high spectral resolution, and independent and sharp characteristic peaks. Combined detection of these three techniques can achieve complementary characterization of elemental composition and molecular vibrational information, enabling comprehensive determination of material composition, molecular structure, and phase information. However, the three types of spectral signals differ significantly in intensity: LIBS is a strong signal, while Raman and fluorescence are weak signals, with Raman signals being particularly weak and susceptible to interference from fluorescence background and sunlight. Balancing signal separation and the stability of each technique during combined detection has become a key bottleneck restricting its application. Furthermore, in-situ deep space exploration imposes strict constraints on the size, weight, and power consumption of equipment, while also requiring the equipment to possess multi-dimensional and high-precision material component identification capabilities.

[0003] Existing spectroscopic detection equipment often employs a multi-source, discrete architecture with low optical path reuse and integration. Even when combined detection is used, it typically involves multiple independent lasers for excitation, independent emission and reception optical paths, and multiple spectrometers and detectors deployed in parallel, resulting in a large overall size, weight, and power consumption. Multiple sources struggle to achieve coaxial, point-to-point focusing, leading to spatial misalignment of different spectral detection spots, making it difficult to accurately correlate elemental, phase, and organic matter data, resulting in significant quantitative inversion errors. Furthermore, traditional equipment usually requires an additional independent illumination source for image aiming at the measurement points, further increasing hardware redundancy.

[0004] In terms of detection adaptability and range, existing fixed optical path systems have a fixed focal length, enabling precise focusing only on targets at fixed distances. They cannot adapt to the needs of adaptive detection across uneven terrain and varying detection distances, resulting in significant signal-to-noise ratio degradation for both long-range and short-range targets. Furthermore, traditional equipment often only supports single-point fixed-point detection, making it difficult to achieve large-area array scanning detection. This leads to low detection efficiency, poor regional coverage, and an inability to meet the need for acquiring spatial distribution characteristics of surface materials over large areas, resulting in insufficient completeness of regional detection data.

[0005] In terms of spectral back-end and data interpretation, multispectral discrete detection requires the configuration of multiple spectrometers and detectors, which consumes a lot of payload resources; and there is a lack of a multi-dimensional spectral data collaborative interpretation mechanism. Single spectral detection suffers from serious matrix effects, large element quantification errors, and low accuracy in identifying minerals and organic matter, making it difficult to achieve integrated and accurate identification of elemental composition, molecular structure, crystal phase, hydration characteristics and organic matter.

[0006] Therefore, there is an urgent need for an integrated system that is lightweight, compact, has a common optical path, adaptive focusing, two-dimensional scanning, and supports multi-spectral, multi-dimensional joint detection, in order to solve engineering and scientific problems such as multiple separate devices, bulky size, misaligned light spots, resource redundancy, and poor band compatibility. Summary of the Invention

[0007] To address the aforementioned technical problems, this invention provides a joint detection system and method for morphology, LIBS, Raman, and fluorescence spectroscopy. A single laser coaxially outputs three-band lasers of 266 / 532 / 1064nm. After two-dimensional scanning via common aperture and common optical path transceiver and adaptive focusing, LIBS, ultraviolet Raman, and fluorescence spectra are simultaneously acquired by a dual-period grating single-detector broadband spectrometer. Combined with on-orbit self-calibration and multispectral collaborative interpretation, this system achieves lightweight, high-precision, and all-terrain adaptable integrated in-situ detection of elements, phases, and hydrated / organic matter.

[0008] To achieve the above objectives, the present invention adopts the following technical solution:

[0009] A combined morphology, LIBS, Raman, and fluorescence spectroscopy detection system includes a three-in-one laser emission unit, a common-aperture telescope transceiver relay unit, an adaptive focusing unit, a two-dimensional scanning detection unit, a dual-period grating broadband spectrometer unit, and an on-orbit fully automatic self-calibration unit, wherein:

[0010] The three-in-one laser emitting unit is used to output three-band lasers of 266nm, 532nm and 1064nm, and outputs the three-band lasers coaxially and at the same point to the common aperture telescope transceiver beam splitter unit.

[0011] The common aperture telescope transceiver beam splitter unit is used to coaxially focus the three-band lasers onto the target to excite LIBS, ultraviolet Raman, and fluorescence spectra, as well as microscopic image illumination. After splitting and suppressing stray light, the LIBS, ultraviolet Raman, and fluorescence spectra are coupled into the dual-period grating wideband spectrometer unit.

[0012] The dual-period grating wideband spectrometer unit is used to collimate the input spectrum, perform dual-period grating spectral dispersion and two-stage convergence focusing, and simultaneously acquire LIBS spectrum, ultraviolet Raman spectrum and fluorescence spectrum by a single area array detector in a time-division manner.

[0013] The adaptive focusing unit is used to drive the common aperture telescope transceiver beam splitter unit to dynamically focus during operation based on the object-side distance between the device and the target, so that the laser and the reflected light signal remain focused at the target.

[0014] The two-dimensional scanning detection unit is used to work in conjunction with the adaptive focusing unit to drive the common aperture telescope transceiver beam splitter to switch measurement points, thereby achieving single-point fixed-point detection or area array gridded scanning detection.

[0015] The on-orbit fully automatic self-calibration unit is used to perform on-orbit calibration of laser energy, spectral wavelength and responsivity during the operation of the three-in-one laser emitting unit and the dual-period grating wideband spectrometer unit.

[0016] Furthermore, the three-in-one laser emitting unit uses a single laser sharing a pump source and crystal. It first outputs a 1064nm fundamental frequency laser through cascaded frequency doubling, then outputs a 532nm laser through a first second frequency doubling element, and finally outputs a 266nm laser through a second second frequency doubling element. The three laser bands are output from the same output port. The 266nm laser is used to excite ultraviolet Raman and fluorescence spectra, the 1064nm laser is used to excite LIBS spectra, and the 532nm laser is output as a uniform illumination spot for the microscope camera through a diffractive optical element flat-top beam shaper.

[0017] Furthermore, the common-aperture telescope transceiver beam splitter unit adopts a single-aperture coaxial optical path, including a scanning pointing mirror group, a telescope objective lens, a focusing mirror group, a microscope camera dichroic prism, and a telescope eyepiece, which work together with a first dichroic mirror, a second dichroic mirror, a 266nm long-pass filter, and an ultraviolet-visible dichroic filter. The emission and reception optical paths are completely multiplexed. The returned light signal is sequentially separated into 532nm spectral band light by the microscope camera dichroic prism and sent to the focal plane of the microscope camera. The remaining spectral band light is filtered out step by step by the telescope eyepiece, the first dichroic mirror, the second dichroic mirror, the 266nm long-pass filter, and the ultraviolet-visible dichroic filter to remove residual excitation laser stray light. After separating the effective signals of the ultraviolet Raman spectrum, fluorescence spectrum, and LIBS spectrum, they are coupled into the dual-period grating broadband spectrometer unit.

[0018] Furthermore, the dual-period grating wideband spectrometer unit is configured with only one set of beam-splitting optical path, a single dual-period diffraction grating, and a single area array detector. The ultraviolet and visible light are separated by an ultraviolet-visible diffractor and then guided by two optical fibers to different positions on the spectrometer collimating lens. They are collimated into two parallel beams, which are then split by the dual-period diffraction grating and focused into the detector focal plane by a first and a second converging lens. The dual-period diffraction grating has a segmented diffraction structure, with the short-period grating adapted to the 266nm to 500nm ultraviolet band and the long-period grating adapted to the 500nm to 800nm ​​visible to near-infrared band.

[0019] Furthermore, the adaptive focusing unit includes an electric focusing lens group, a range sensing module, and a closed-loop focusing control module. The range sensing module collects the object distance in real time by analyzing the relationship between the position of the focusing lens group and the image sharpness of the focal plane of the microscope camera. The closed-loop focusing control module drives the focusing lens group to move along the optical axis through the microscope camera focusing and imaging algorithm, and automatically matches the optimal focal length within the object distance range of 50mm to 250mm.

[0020] Furthermore, the two-dimensional scanning detection unit includes a two-dimensional electric scanning mechanism and a pointing mechanism, and has a single-point fixed-point mode and a grid scanning mode; the single-point fixed-point mode locks a single measurement point for spectral acquisition, and the grid scanning mode completes grid-based full-coverage scanning of the target area by horizontal and vertical bidirectional precise displacement at predetermined steps.

[0021] Furthermore, the on-orbit fully automatic self-calibration unit includes a 1064nm translation switching mirror, a laser absorber, and a trigger fiber; when the 1064nm translation switching mirror cuts out the optical path, a 1064nm laser is incident on the laser absorber, and the pulse energy is collected in real time to correct the laser power drift; the trigger fiber guides a monochromatic laser to correct the detector wavelength shift and responsivity attenuation; calibration is automatically started after a fixed number of measurement points are detected.

[0022] Furthermore, the 1064nm translation switching mirror enters the optical path when LIBS spectral excitation is required, allowing the 1064nm laser to be transmitted through the beam expander and the second dichroic mirror to the first dichroic mirror and then guided into the main optical path of the telescope, while simultaneously detecting the laser energy; when LIBS spectral excitation is not required, the optical path is exited, allowing the 1064nm laser to be guided into the laser absorber for laser energy calibration and removal of 1064nm energy from the excitation optical path.

[0023] On the other hand, the present invention provides a method for joint detection of morphology, LIBS, Raman and fluorescence spectroscopy, applied to the aforementioned system, including:

[0024] The system initializes and performs on-orbit self-calibration, controls the 1064nm translation switching mirror to cut out the optical path, uses the laser absorber to complete the LIBS excitation energy calibration, corrects the spectral response by introducing reference data through the trigger fiber, and turns on the 532nm DOE uniform illumination branch to provide supplementary light for the microscope camera.

[0025] Adaptive distance focusing: The distance between the device and the target is obtained by focusing and ranging through a microscope camera, and the focusing lens group is driven to match the optimal focal length.

[0026] Detection mode selection and two-dimensional scanning deployment: Select single-point detection mode or two-dimensional area array scanning mode and complete fixed-point pointing or gridded point deployment;

[0027] Three lasers are used for time-division co-probe detection. According to the excitation time interval, the ultraviolet Raman and fluorescence spectra are first excited by a 266nm ultraviolet pulse laser, then the LIBS spectrum is generated by breaking down the sample with a 1064nm near-infrared pulse laser, and a 532nm visible pulse laser is used as the supplementary light for the microscope camera.

[0028] The common-path spectral splitting and stray light suppression detects the backlight signals of the LIBS spectrum, ultraviolet Raman spectrum, and fluorescence spectrum generated by the target under stimulation. These signals are transmitted back along the original common-aperture optical path and then filtered out by the microscope camera dichroic prism, the first dichroic mirror, the second dichroic mirror, the 266nm long-pass filter, and the ultraviolet-visible dichroic filter to remove residual excitation laser stray light. After separating the effective spectral signals, they are input into the dual-period grating broadband spectrometer unit.

[0029] The single detector acquires the full-band spectrum synchronously, while the mixed spectrum is collimated, split by a dual-period grating, and converged by two stages before being acquired by a single area array detector in a time-division manner.

[0030] Two-dimensional area array iterative detection involves repeating the focusing, detection, and acquisition steps point by point in the area array scanning mode.

[0031] Multispectral collaborative interpretation and component inversion, integrating LIBS elemental quantification, ultraviolet Raman phase identification, fluorescence hydration and organic matter identification, and outputting comprehensive detection results from microscopic image morphology data;

[0032] Periodic iterative calibration: After each fixed number of measurement points are detected, on-orbit self-calibration is automatically initiated.

[0033] Furthermore, the multispectral collaborative interpretation and component inversion includes: quantitatively inverting the content of major and minor elements and trace elements of the target using LIBS spectroscopy; analyzing the mineral crystal structure, determining the phase type, and identifying organic matter using 266nm ultraviolet Raman spectroscopy; identifying hydrated minerals and trace organic matter using fluorescence spectroscopy; describing the morphological characteristics of the detected target using images from a microscope camera; and fusion of multidimensional data to output a comprehensive detection result including element content, mineral type, hydration characteristics, and organic matter form.

[0034] Thirdly, the present invention provides an electronic device, comprising: one or more processors; and a memory for storing one or more programs; wherein, when the one or more programs are executed by the one or more processors, the one or more processors enable the aforementioned morphology, LIBS, Raman and fluorescence spectroscopy joint detection method.

[0035] Fourthly, the present invention provides a computer-readable storage medium having executable instructions stored thereon, which, when executed by a processor, enable the processor to implement the aforementioned morphology, LIBS, Raman and fluorescence spectroscopy joint detection method.

[0036] The beneficial effects of this invention are as follows:

[0037] It employs a single laser to coaxially output three-band lasers at 266, 532, and 1064 nm, with precise functional division. 266 nm excites ultraviolet Raman and fluorescence, 1064 nm excites LIBS, and 532 nm is used for supplementary illumination in microscopic imaging. This avoids the redundancy of multiple discrete light sources, and coaxial excitation eliminates the spatial misalignment of multiple individual laser excitation spectral signals, significantly improving the accuracy of the correspondence between elemental, phase, and organic matter data.

[0038] Employing a common aperture, common optical path transceiver architecture and a dual-period grating single detector wideband spectrometer, it requires only a single optical path, a single grating, and a single area array detector to cover the entire ultraviolet to near-infrared band, significantly reducing the size, weight, and power consumption of the equipment, and adapting to the constraints of lightweight deep-space payloads and robotic arm mounting.

[0039] It integrates adaptive focusing and two-dimensional scanning mechanisms, enabling automatic and precise focusing within an object distance of 50–250 mm. It also balances high-precision single-point detection with gridded scanning of target areas, effectively adapting to complex terrain and improving regional detection efficiency and data integrity.

[0040] The built-in standard-free on-orbit self-calibration optical path can correct laser energy drift, wavelength shift and detector response attenuation in real time, ensuring the consistency and reliability of long-term on-orbit detection data.

[0041] The system is equipped with a multispectral collaborative interpretation method that integrates LIBS elemental quantification, ultraviolet Raman phase identification, and fluorescence hydration / organic matter identification. This effectively suppresses the matrix effect of a single spectrum and achieves high-precision integrated identification of elemental composition, mineral type, hydration characteristics, and trace organic matter. Attached Figure Description

[0042] Figure 1 This is a diagram showing the morphology, LIBS, Raman, and fluorescence spectroscopy joint detection system architecture of the present invention;

[0043] Figure 2 This is a flowchart of the morphology, LIBS, Raman and fluorescence spectroscopy joint detection method of the present invention.

[0044] Figure label:

[0045] 1.1-Pump source and crystal, 1.2-First second harmonic generation element, 1.3-Second second harmonic generation element, 1.4-Light output port;

[0046] 266nm emission optics: 2.1-First 266nm reflector, 2.2-Second 266nm reflector, 2.3-First dichroic mirror;

[0047] 532nm emission optics: 3.1-First 532nm reflector, 3.2-Second 532nm reflector, 3.3-532nm laser converging mirror, 3.4-DOE flat-top beam shaper, 3.5-Trigger fiber;

[0048] 1064nm emission optics: 4.1-1064nm translation switching mirror, 4.2-laser absorber, 4.3-beam expander, 4.4-second dichroic mirror;

[0049] 5.1-Telescopic eyepiece, 5.2-Microscopic camera dichroic prism, 5.3-Focusing lens group, 5.4-Telescopic objective lens, 5.5-Scanning pointing lens group;

[0050] 6.1-266nm long-pass filter, 6.2-UV-Vis dichroic filter, 6.3-Spectrometer collimating lens, 6.4-Double-period diffraction grating, 6.5-First converging lens, 6.6-Second converging lens, 6.7-Detector focal plane;

[0051] 7 - Focal plane of the microscope camera; 8 - Detection target. Detailed Implementation

[0052] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0053] This invention aims to provide a joint detection system and method for morphology, LIBS, Raman, and fluorescence spectroscopy. Relying on a shared-aperture, shared-optical-path integrated framework, it significantly reduces the size, weight, and power consumption of the equipment. The core innovation lies in: employing a single three-in-one laser coaxially outputting 266 / 532 / 1064nm laser light, precisely dividing the excitation of ultraviolet Raman and fluorescence spectroscopy, LIBS spectroscopy, and microscopic imaging illumination. This breaks through the traditional discrete architecture of multiple lasers, achieving a hardware simplification rate of over 60%. Coaxial excitation eliminates multi-spot misalignment, and rational division of labor avoids light source redundancy. All laser emission, spectral acquisition, and imaging illumination share the same directional telescope optical system, with only a single optical window and a single pointing mechanism, significantly reducing the size, weight, and power consumption of deep-space payloads, adapting to the constraints of landers or rovers. The closed-loop adaptive focusing system covers object-space distances of 50-250mm and can optimize the focal length in real time for celestial surfaces with unevenness, solving the problems of signal attenuation and imaging blurring for distant and near targets in fixed-focal-length equipment. Integrating a high-precision two-dimensional scanning mechanism, it combines high-precision single-point measurement with gridded scanning of target areas, rapidly acquiring the spatial distribution characteristics of surface materials. Its detection efficiency and regional data integrity far surpass traditional single-point equipment. Employing a single set of post-spectral optical paths, dual-period gratings, and a single area array detector, it simultaneously captures ultraviolet-to-near-infrared full-band ultraviolet Raman, fluorescence, and broadband LIBS signals, abandoning the parallel approach of multispectral analyzers and achieving extreme lightweight design. A three-dimensional spectral interpretation model of "elemental quantification - crystal phase - hydration / organic matter" is established to suppress matrix effects and improve identification accuracy. A built-in standard-free on-orbit self-calibration optical path corrects for environmental and device aging errors in real time, ensuring the reliability of long-term deep space exploration data.

[0054] like Figure 1 As shown, the system is a highly integrated optical detection architecture, comprising a three-in-one laser emitting unit, a common-aperture telescope-transmitter-splitter relay unit, an adaptive focusing unit, a two-dimensional scanning detection unit, a dual-period grating wide-band spectrometer unit, and an on-orbit fully automatic self-calibration unit. It can achieve coaxial point excitation of lasers in three bands (266, 532, and 1064 nm), simultaneously acquiring LIBS spectra, Raman and fluorescence spectra, and microscopic images in a time-division manner. It completes full-band multidimensional spectral detection using a single laser, a single optical path, a single spectrometer, and a single detector. Specifically:

[0055] The three-in-one laser emitting unit is used to output three-band lasers of 266nm, 532nm and 1064nm, and outputs the three-band lasers coaxially and at the same point to the common aperture telescope transceiver beam splitter unit.

[0056] The common aperture telescope transceiver beam splitter unit is used to coaxially focus the three-band lasers onto the target to excite LIBS, ultraviolet Raman and fluorescence spectra, and after splitting and suppressing stray light, the LIBS, ultraviolet Raman and fluorescence spectra are coupled into the dual-period grating wideband spectrometer unit.

[0057] The dual-period grating wideband spectrometer unit is used to collimate the input spectrum, perform dual-period grating spectral dispersion and two-stage convergence focusing, and simultaneously acquire LIBS spectrum, ultraviolet Raman spectrum and fluorescence spectrum by a single area array detector in a time-division manner.

[0058] The adaptive focusing unit is used to drive the common aperture telescope transceiver beam splitter unit to dynamically focus during operation based on the object-side distance between the device and the target, so that the laser and the reflected light signal remain focused at the target.

[0059] The two-dimensional scanning detection unit is used to work in conjunction with the adaptive focusing unit to drive the common aperture telescope transceiver beam splitter to switch measurement points, thereby achieving single-point fixed-point detection or gridded scanning detection of the target area.

[0060] The on-orbit fully automatic self-calibration unit is used to perform on-orbit calibration of laser energy, spectral wavelength and responsivity during the operation of the three-in-one laser emitting unit and the dual-period grating wideband spectrometer unit.

[0061] The specific composition and function of each unit are described below.

[0062] The three-in-one laser emitting unit uses a single laser to output three coaxial pulsed lasers: 266nm ultraviolet, 532nm visible, and 1064nm near-infrared. These three lasers share a pump source and crystal 1.1. Through cascaded frequency doubling, the fundamental frequency of 1064nm is first output, then 532nm is output via the first second frequency doubling element 1.2, and finally 266nm is output via the second second frequency doubling element 1.3. All three wavelengths are output from the same output port 1.4. The three wavelengths have dedicated functions, eliminating the redundancy of multiple separate light sources.

[0063] 266nm ultraviolet laser: used to excite the ultraviolet Raman and fluorescence spectral signals of target 8, making up for the shortcomings of traditional visible light Raman in identifying trace organic matter and water-bearing minerals;

[0064] 532nm visible laser: The beam splitter is connected to the DOE flat-top beam shaper 3.4, which outputs a uniform downward illumination spot as visible light to illuminate the target 8. No additional illumination source is required, which can compensate for the lack of light in microscopic imaging in dark scenes.

[0065] 1064nm near-infrared laser: As a LIBS excitation source, the pulsed laser breaks down the sample to generate LIBS spectral signals, enabling quantitative detection of major and minor elements and trace elements.

[0066] As mentioned earlier, the three-band lasers coexist and are output from the same output port 1.4. They then pass through multiple folding mirrors, switching mirrors, absorbers, optical fibers, and converging mirrors to achieve simultaneous output of the three-band lasers via a common optical path. Specifically:

[0067] The 266nm laser light is reflected by the first 266nm mirror 2.1, then by the second 266nm mirror 2.2, and finally reaches the first dichroic mirror 2.3, and is then guided into the main optical path of the telescope.

[0068] A 532nm laser beam is transmitted through a first 266nm reflector 2.1, then reflected by a first 532nm reflector 3.1 and a second 532nm reflector 3.2, and reaches a 532nm laser converging mirror 3.3. The laser beam is then guided into an optical fiber and directed to a DOE flat-top beam shaper 3.4, and illuminates the target 8 through an open optical path and a scanning pointing mirror group 5.5.

[0069] A 1064nm laser beam is transmitted through a first 266nm reflector 2.1 and then through a first 532nm reflector 3.1. The direction of the 1064nm laser beam is controlled by a 1064nm translational switching mirror 4.1 with an angle-sensitive electrically switched structure. When LIBS excitation is required, the 1064nm translational switching mirror 4.1 enters the optical path, allowing the 1064nm laser beam to pass through a beam expander 4.3 and a second dichroic mirror 4.4, reaching the first dichroic mirror 2.3, and finally entering the main optical path of the telescope to excite the LIBS signal and detect the laser energy. When LIBS excitation is not required, the 1064nm translational switching mirror 4.1 exits the optical path, allowing the 1064nm laser beam to enter the laser absorber 4.2 for laser energy calibration and removal of 1064nm energy from the excitation optical path.

[0070] In addition, while the second 532nm reflector 3.2 reflects the 532nm laser, some of the 532nm and 1064nm lasers are transmitted. These are coupled through the trigger fiber 3.5 as the 1064nm trigger and standard laser signal. Together with the laser energy in the laser absorber 4.2, they provide an on-orbit wavelength and responsivity calibration benchmark for the spectral system.

[0071] The common-aperture transceiver beam splitter unit is the lightweight core structure of the system. It adopts a single-aperture coaxial optical path design, integrating the scanning pointing mirror group 5.5, the telescope objective lens group 5.4, the focusing mirror group 5.3, the microscope dichroic prism 5.2, and the telescope eyepiece group 5.1. Combined with the first dichroic mirror 2.3, the second dichroic mirror 4.4, the 266nm long-pass filter 6.1, and the UV-Vis dichroic filter 6.2, it achieves complete multiplexing of the laser emission, signal return, and imaging illumination optical paths. Specifically:

[0072] The emission optical path: The 266 / 532 / 1064nm laser introduced through the three-in-one laser emission unit is focused on the same measuring point on the ground surface, namely the detection target 8, by the focusing telescope group and the scanning pointing mechanism. The laser spots are completely superimposed, eliminating the spatial misalignment of the multispectral signal.

[0073] Receiving optical path: The LIBS spectrum, ultraviolet Raman spectrum, and fluorescence spectrum generated by the stimulated target are transmitted back along the original optical path, realizing the complete multiplexing of the laser emission and signal receiving optical paths;

[0074] Multi-stage stray light suppression: The back-transmitted light signal passes sequentially through the microscope camera's dichroic prism 5.2, separating the 532nm spectral band light to the microscope camera's focal plane 7. The remaining spectral band light then passes through the telescope eyepiece 5.1, the first dichroic mirror 2.3, the second dichroic mirror 4.4, the 266nm long-pass filter 6.1, and the UV-Vis dichroic filter 6.2, filtering out residual excitation laser stray light step by step, accurately separating the effective signals of UV Raman, fluorescence, and LIBS, and finally coupling the optical fiber to send it into the spectrometer, ensuring high signal-to-noise ratio acquisition of weak spectral signals.

[0075] The dual-period grating broadband spectrometer unit is a single-detector integrated architecture, configured with only one set of beam-splitting optical path, a single dual-period grating, and a single area array detector, achieving full-band compatible acquisition from ultraviolet to near-infrared:

[0076] Optical path: The mixed light signal passes through the first dichroic mirror 2.3, the second dichroic mirror 4.4, the 266nm long-pass filter 6.1, and the UV-Vis dichroic filter 6.2, and is separated into UV and visible light. These are then introduced into the spectrometer's optical path via two optical fibers. After adjusting the beam angle so that the two light spots are located at different positions of the spectrometer's collimating lens 6.3, they are collimated into two parallel beams. These beams are then split by a double-period diffraction grating 6.4, and then focused in two stages by the first and second converging lenses 6.5 and 6.6, finally entering the detector's focal plane at two positions on 6.7 (the blue and green light paths in the diagram clearly indicate the entire optical transmission process). Only one set of optics and one detector are configured, eliminating the redundancy of multi-optical paths and multi-detector structures, thus maximizing the reduction of equipment size and power consumption.

[0077] The dual-period diffraction grating 6.4 adopts a segmented diffraction structure. The short-period grating is adapted to the 266-500nm ultraviolet band, covering the Raman and ultraviolet-visible fluorescence signals in the 266nm ultraviolet band, and also taking into account the LIBS ultraviolet-visible plasmonic spectrum. The long-period grating is adapted to the 500-800nm ​​visible-near-infrared band, covering the LIBS visible-near-infrared plasmonic spectrum.

[0078] The adaptive focusing unit integrates a high-precision electric focusing lens group, a ranging sensor module, and a closed-loop focusing control module. It can detect the object distance between the device and the target 8 in real time, and automatically drive the focusing lens group to move according to different terrains and different detection distances to complete the adaptive adjustment of the optical path focal length.

[0079] Motorized focusing lens assembly: The focusing lens assembly 5.3 is adjusted by a high-precision stepper motor and focusing mechanism to achieve the best optical efficiency for transmission and reception;

[0080] The ranging sensor module: By adjusting and analyzing the relationship between the position of the focusing lens group 5.3 and the imaging sharpness of the focal plane 7 of the microscope camera, the distance between the device and the target object is collected in real time;

[0081] Closed-loop focusing control module: Through the focusing and imaging algorithm of the microscope camera, the focusing lens group 5.3 is automatically driven to move along the optical axis, and the optimal focal length is automatically matched within the range of 50mm~250mm. This ensures that the laser excitation spot is always focused on the surface of the target 8 under close-range, medium-range, and long-range detection conditions, and the signal-to-noise ratio of the spectral signal acquisition is stable.

[0082] The two-dimensional scanning detection unit is equipped with a high-precision two-dimensional electric scanning mechanism and a pointing mechanism, and is linked with the adaptive focusing unit, providing dual working modes:

[0083] (1) Single-point fixed-point mode: Locking a single measurement point for long-term accurate spectral acquisition;

[0084] (2) Grid scanning mode: Through the horizontal and vertical bidirectional precision displacement adjustment of the two-dimensional scanning mechanism, the grid-based full coverage scanning of the target area is completed according to the predetermined step length, and the distribution data of material components in the whole area are collected, which greatly improves the regional detection efficiency and the scanning positioning accuracy is ≤0.1mm.

[0085] The on-orbit fully automatic self-calibration unit relies on a 1064nm translation switching mirror 4.1, a laser absorber 4.2, and a trigger fiber 3.5 to form an integrated calibration optical path, eliminating the need for external standard samples.

[0086] (1) Energy calibration: 1064nm translation switching mirror 4.1 cuts out the optical path, 1064nm laser is incident on laser absorber 4.2, pulse energy is collected in real time, and laser power drift is corrected;

[0087] (2) Spectral calibration: A monochromatic laser is introduced through the trigger fiber 3.5 to correct the detector wavelength shift and responsivity attenuation;

[0088] (3) Automated calibration process: Automatically starts after each fixed measurement point detection is completed. The single calibration time is ≤2s, which does not occupy the effective detection time. It can complete laser energy calibration, spectral wavelength drift correction and detector response deviation correction in real time on the track, effectively offsetting the system errors caused by extreme temperature changes in deep space, space irradiation and device aging, and ensuring the stability and consistency of long-term detection data of the equipment.

[0089] On the other hand, such as Figure 2 As shown, this invention provides a joint detection method based on morphology, LIBS, Raman, and fluorescence spectroscopy. This method is implemented using the aforementioned lightweight integrated detection system, integrating adaptive focusing, two-dimensional area array scanning, three-laser time-division co-point excitation, full-band synchronous spectral acquisition, and multi-source data collaborative interpretation technologies. Specifically, it includes the following steps:

[0090] S1. System Initialization and On-orbit Self-calibration: The device completes optical path and circuit self-test upon power-up, controls the 1064nm translation switching mirror 4.1 to cut out the optical path, uses the laser absorber 4.2 to complete LIBS excitation energy calibration, and imports the reference correction spectral response through the trigger fiber 3.5; turns on the 532nm DOE flat-top beam shaper 3.4 to uniformly illuminate the microscope camera, and completes the visualization and positioning of the target area.

[0091] S2, Adaptive Distance Focusing: The object distance between the device and the target 8 is obtained through the focusing and ranging algorithm of the microscope camera. The focusing control module drives the focusing lens group 5.3 to automatically match the optimal focal length, so as to achieve precise focusing of targets at different distances and ensure the focusing accuracy of the laser spot and the imaging and spectral quality.

[0092] S3. Detection Mode Selection and 2D Scan Layout: Select either single-point detection mode or 2D area scan mode according to detection requirements; if single-point detection is used, plan the displacement of the electric mechanism in the horizontal and vertical directions, and control the 2D electric scanning mechanism to complete the fixed-point pointing; if area scan is used, plan the gridded sampling points, scanning step size and area boundary, and control the 2D electric scanning mechanism to complete the gridded point layout of the detection area.

[0093] S4. Three-laser time-division co-probe: A 1064nm translational switching mirror (4.1) cuts out the optical path, with an excitation timing interval of 100–500 ns to avoid crosstalk between the 266nm and 1064nm excitation spectral signals.

[0094] (1) A 1064nm translation switching mirror 4.1 is cut out, and a single 266nm ultraviolet pulse laser output is used to excite the detection target 8 to generate ultraviolet Raman and fluorescence spectra;

[0095] (2) The 1064nm translation switching mirror 4.1 is inserted, and the 1064nm near-infrared pulsed laser output is irradiated together with the 266nm ultraviolet pulsed laser to break down the sample and generate LIBS spectrum.

[0096] (3) The 532nm visible pulsed laser is introduced into the DOE flat-top beam shaper 3.4 through the 532nm laser converging mirror 3.3 and the optical fiber to output a flat-top beam, which uniformly illuminates the detection target 8 and provides supplementary light for the microscope camera.

[0097] S5. Common-path spectral splitting and stray light suppression: The multi-dimensional spectral backlight signal generated by the detection target 8 is transmitted back along the original common-aperture optical path. It is filtered out by multiple stages of the microscope camera's dichroic prism 5.2, the first dichroic mirror 2.3 and the second dichroic mirror 4.4, and the 266nm long-pass filter 6.1 to remove stray light returned by the excitation laser. The effective signals of the ultraviolet Raman, fluorescence, and LIBS full-band spectra are separated and coupled into the broadband spectrometer.

[0098] S6. Single detector full-band spectrum synchronous acquisition: The mixed spectral signal is collimated by the spectrometer, split by the dual-period grating, and focused by two stages. The raw data such as 266nm ultraviolet Raman spectrum, fluorescence spectrum, and LIBS spectrum are acquired synchronously in time-division by a single detector.

[0099] S7. Two-dimensional array iterative detection: In the array scanning mode, the two-dimensional scanning mechanism is driven to move point by point, repeating steps S2-S6 to complete the full-coverage spectral detection of the entire target area and obtain a regionalized multispectral dataset.

[0100] S8. Multispectral collaborative interpretation and component inversion: Integrating three types of spectral data for joint analysis to suppress single-spectral matrix effects;

[0101] (1) LIBS spectral quantitative inversion of target primary and secondary quantities and trace element content;

[0102] (2) 266nm ultraviolet Raman spectroscopy is used to analyze the mineral crystal structure, determine the phase type, and identify organic matter;

[0103] (3) Fluorescence spectroscopy identifies hydrated minerals and trace organic matter;

[0104] (4) Microscopic camera image description detects the morphological features of the target;

[0105] (5) Multidimensional data fusion outputs the complete component identification results of the target, including comprehensive detection results such as element content, mineral type, hydration characteristics, and organic matter form.

[0106] S9. Periodic Iterative Calibration: After each fixed number of measurement points are detected, the S1 self-calibration process is automatically started to correct systematic errors caused by extreme temperature changes in deep space, space irradiation, and device aging, ensuring long-term detection consistency.

[0107] Example

[0108] This invention is applied to a lightweight deep-space probe payload, integrating a lightweight shell with a total weight of ≤6kg and a peak power consumption of ≤75W, making it fully compatible with lunar, Martian, and other celestial body landing or rover platforms.

[0109] (1) The pulse width of the three-in-one laser is 2-10ns, and the single pulse energy is adjustable: 266nm (0-100uJ), 532nm (0-100uJ), 1064nm (0-200uJ). The uniformity of the 532nm DOE homogenization spot is ≥90%, which meets the requirements of microscopic imaging supplementary lighting.

[0110] (2) The adaptive focusing unit has a focusing response time of ≤200ms and a focusing accuracy of better than 5μm across the entire distance range; the two-dimensional scanning mechanism has a bidirectional stroke of ≥50mm and a scanning positioning accuracy of ≤0.1mm, which can realize large-area grid-based detection.

[0111] (3) The dual-period grating spectrometer covers the entire 266-840nm band, with a grating line density of 1180 lines / mm in the ultraviolet band and 700 lines / mm in the visible-near infrared band; the detector adopts an uncooled CMOS detector, which responds to the full spectrum range; the on-orbit self-calibration single calibration time is ≤2s, which does not occupy the effective detection time and can realize unattended fully automatic calibration.

[0112] Thirdly, the present invention provides an electronic device, comprising: one or more processors; and a memory for storing one or more programs; wherein, when the one or more programs are executed by the one or more processors, the one or more processors enable the aforementioned morphology, LIBS, Raman and fluorescence spectroscopy joint detection method.

[0113] Fourthly, the present invention provides a computer-readable storage medium having executable instructions stored thereon, which, when executed by a processor, enable the processor to implement the aforementioned morphology, LIBS, Raman and fluorescence spectroscopy joint detection method.

[0114] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A combined detection system for morphology, LIBS, Raman, and fluorescence spectroscopy, characterized in that, It includes a three-in-one laser emitting unit, a common aperture telescope transceiver relay unit, an adaptive focusing unit, a two-dimensional scanning detection unit, a dual-period grating broadband spectrometer unit, and an on-orbit fully automatic self-calibration unit, among which: The three-in-one laser emitting unit is used to output three-band lasers of 266nm, 532nm and 1064nm, and outputs the three-band lasers coaxially and at the same point to the common aperture telescope transceiver beam splitter unit. The common aperture telescope transceiver beam splitter unit is used to coaxially focus the three-band lasers onto the target to excite LIBS, ultraviolet Raman, and fluorescence spectra, as well as microscopic image illumination. After splitting and suppressing stray light, the LIBS, ultraviolet Raman, and fluorescence spectra are coupled into the dual-period grating wideband spectrometer unit. The dual-period grating wideband spectrometer unit is used to collimate the input spectrum, perform dual-period grating spectral dispersion and two-stage convergence focusing, and simultaneously acquire LIBS spectrum, ultraviolet Raman spectrum and fluorescence spectrum by a single area array detector in a time-division manner. The adaptive focusing unit is used to drive the common aperture telescope transceiver beam splitter unit to dynamically focus during operation based on the object-side distance between the device and the target, so that the laser and the reflected light signal remain focused at the target. The two-dimensional scanning detection unit is used to work in conjunction with the adaptive focusing unit to drive the common aperture telescope transceiver beam splitter to switch measurement points, thereby achieving single-point fixed-point detection or area array gridded scanning detection. The on-orbit fully automatic self-calibration unit is used to perform on-orbit calibration of laser energy, spectral wavelength and responsivity during the operation of the three-in-one laser emitting unit and the dual-period grating wideband spectrometer unit.

2. The morphology, LIBS, Raman, and fluorescence spectroscopy combined detection system according to claim 1, characterized in that, The three-in-one laser emitting unit uses a single laser sharing a pump source and crystal. It first outputs a 1064nm fundamental frequency laser through cascaded frequency doubling, then outputs a 532nm laser through the first second frequency doubling element, and finally outputs a 266nm laser through the second second frequency doubling element. The three laser bands are output from the same output port. The 266nm laser is used to excite ultraviolet Raman and fluorescence spectra, the 1064nm laser is used to excite LIBS spectra, and the 532nm laser is output as a uniform illumination spot for the microscope camera through a diffractive optical element flat-top beam shaper.

3. The morphology, LIBS, Raman, and fluorescence spectroscopy combined detection system according to claim 1, characterized in that, The common-aperture telescope transceiver beam splitter unit adopts a single-aperture coaxial optical path, including a scanning pointing mirror group, a telescope objective lens, a focusing mirror group, a microscope camera dichroic prism, and a telescope eyepiece. It works together with a first dichroic mirror, a second dichroic mirror, a 266nm long-pass filter, and an ultraviolet-visible dichroic filter. The emission and reception optical paths are completely multiplexed. The returned light signal is sequentially separated into 532nm spectral band light by the microscope camera dichroic prism and sent to the focal plane of the microscope camera. The remaining spectral band light is filtered out step by step by the telescope eyepiece, the first dichroic mirror, the second dichroic mirror, the 266nm long-pass filter, and the ultraviolet-visible dichroic filter to remove residual excitation laser stray light. After separating the effective signals of the ultraviolet Raman spectrum, fluorescence spectrum, and LIBS spectrum, they are coupled into the dual-period grating broadband spectrometer unit.

4. The morphology, LIBS, Raman, and fluorescence spectroscopy combined detection system according to claim 1, characterized in that, The dual-period grating wideband spectrometer unit is equipped with only one beam-splitting optical path, a single dual-period diffraction grating, and a single area array detector. The ultraviolet and visible light are separated by an ultraviolet-visible diffractor and then guided by two optical fibers to different positions on the spectrometer collimating lens. They are collimated into two parallel beams, which are then split by the dual-period diffraction grating and focused into the detector focal plane by a first and a second converging lens. The dual-period diffraction grating has a segmented diffraction structure, with the short-period grating adapted to the 266nm to 500nm ultraviolet band and the long-period grating adapted to the 500nm to 800nm ​​visible to near-infrared band.

5. The morphology, LIBS, Raman, and fluorescence spectroscopy combined detection system according to claim 1, characterized in that, The adaptive focusing unit includes an electric focusing lens group, a range sensing module, and a closed-loop focusing control module. The range sensing module collects the object distance in real time by analyzing the relationship between the position of the focusing lens group and the image sharpness of the focal plane of the microscope camera. The closed-loop focusing control module drives the focusing lens group to move along the optical axis through the microscope camera focusing and imaging algorithm, and automatically matches the optimal focal length within the object distance range of 50mm to 250mm.

6. The morphology, LIBS, Raman, and fluorescence spectroscopy combined detection system according to claim 1, characterized in that, The two-dimensional scanning detection unit includes a two-dimensional electric scanning mechanism and a pointing mechanism, and has a single-point fixed-point mode and a grid scanning mode. In the single-point fixed-point mode, a single measurement point is locked for spectral acquisition, while in the grid scanning mode, the target area is fully covered by grid-based scanning through precise horizontal and vertical displacement at predetermined steps.

7. The morphology, LIBS, Raman, and fluorescence spectroscopy combined detection system according to claim 1, characterized in that, The on-orbit fully automatic self-calibration unit includes a 1064nm translation switching mirror, a laser absorber, and a trigger fiber; when the 1064nm translation switching mirror cuts out the optical path, a 1064nm laser is incident on the laser absorber, and the pulse energy is collected in real time to correct the laser power drift; the trigger fiber guides a monochromatic laser to correct the detector wavelength shift and responsivity attenuation; calibration is automatically started after a fixed number of measurement points are detected.

8. The morphology, LIBS, Raman, and fluorescence spectroscopy combined detection system according to claim 7, characterized in that, The 1064nm translation switching mirror enters the optical path when LIBS spectral excitation is required, allowing the 1064nm laser to be transmitted through the beam expander and the second dichroic mirror to the first dichroic mirror and then guided into the main optical path of the telescope, while simultaneously detecting the laser energy; when LIBS spectral excitation is not required, the optical path is exited, allowing the 1064nm laser to be guided into the laser absorber for laser energy calibration and removal of 1064nm energy in the excitation optical path.

9. A method for joint detection of morphology, LIBS, Raman, and fluorescence spectroscopy, applied to the system described in any one of claims 1-8, characterized in that, include: The system initializes and performs on-orbit self-calibration, controls the 1064nm translation switching mirror to cut out the optical path, uses the laser absorber to complete the LIBS excitation energy calibration, corrects the spectral response by introducing reference data through the trigger fiber, and turns on the 532nm DOE uniform illumination branch to provide supplementary light for the microscope camera. Adaptive distance focusing: The distance between the device and the target is obtained by focusing and ranging through a microscope camera, and the focusing lens group is driven to match the optimal focal length. Detection mode selection and two-dimensional scanning deployment: Select single-point detection mode or two-dimensional area array scanning mode and complete fixed-point pointing or gridded point deployment; Three lasers are used for time-division co-probe detection. According to the excitation time interval, the ultraviolet Raman and fluorescence spectra are first excited by a 266nm ultraviolet pulse laser, then the LIBS spectrum is generated by breaking down the sample with a 1064nm near-infrared pulse laser, and a 532nm visible pulse laser is used as the supplementary light for the microscope camera. The common-path spectral splitting and stray light suppression detects the backlight signals of the LIBS spectrum, ultraviolet Raman spectrum, and fluorescence spectrum generated by the target under stimulation. These signals are transmitted back along the original common-aperture optical path and then filtered out by the microscope camera dichroic prism, the first dichroic mirror, the second dichroic mirror, the 266nm long-pass filter, and the ultraviolet-visible dichroic filter to remove residual excitation laser stray light. After separating the effective spectral signals, they are input into the dual-period grating broadband spectrometer unit. The single detector acquires the full-band spectrum synchronously, while the mixed spectrum is collimated, split by a dual-period grating, and converged by two stages before being acquired by a single area array detector in a time-division manner. Two-dimensional area array iterative detection involves repeating the focusing, detection, and acquisition steps point by point in the area array scanning mode. Multispectral collaborative interpretation and component inversion, integrating LIBS elemental quantification, ultraviolet Raman phase identification, fluorescence hydration and organic matter identification, and outputting comprehensive detection results from microscopic image morphology data; Periodic iterative calibration: After each fixed number of measurement points are detected, on-orbit self-calibration is automatically initiated.

10. The method for joint detection of morphology, LIBS, Raman, and fluorescence spectroscopy according to claim 9, characterized in that, The multispectral collaborative interpretation and component inversion includes: quantitative inversion of the content of major and minor elements and trace elements of the target by LIBS spectroscopy; analysis of mineral crystal structure, determination of phase type and identification of organic matter by 266nm ultraviolet Raman spectroscopy; identification of hydrated minerals and trace organic matter by fluorescence spectroscopy; description of the morphological characteristics of the detected target by microscopic camera images; and fusion of multidimensional data to output a comprehensive detection result including element content, mineral type, hydration characteristics and organic matter form.

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