Optical coupled detection device and method

Abstract

The application discloses an optical combined detection device and method, which comprises the following modules: a light source module comprising a continuous laser source and a pulsed laser source; an optical path coupling and regulation module configured to combine and focus pulsed laser, signal light comb generated by the continuous laser and ultrasonic detection laser at the same point; and separate the reflected light beams into different optical paths to output to corresponding detection units; a detection module comprising a first detection unit for collecting reflected light comb signals, a second detection unit for collecting ultrasonic signals and a third detection unit for collecting laser-induced breakdown spectroscopy signals; a signal processing module comprising a first signal processing system for receiving and processing output signals of the first detection unit, a second signal processing system for receiving and processing output signals of the second detection unit and a third signal processing system for receiving and processing output signals of the third detection unit; and a synchronous control module for controlling the emission time of the pulsed laser and the continuous laser and the processing timing of each signal processing system.

Description

Technical Field

[0001] This invention relates to the field of optical detection technology, and in particular to an optical detection device and method. Background Technology

[0002] High-end manufacturing and other fields are placing higher demands on non-destructive testing. A single testing method is insufficient to comprehensively evaluate the performance of components: LIBS (laser-induced breakdown spectroscopy) can analyze composition but cannot measure morphology and defects; laser ultrasound can measure thickness and defects but is not sensitive to surface morphology; optical combs can measure morphology but cannot provide compositional information.

[0003] The existing combined detection technology has the following shortcomings: First, the time-sharing and location-sharing measurements of each module make it difficult to ensure strict spatial co-location, resulting in information mismatch; second, plasma flashes can interfere with ultrasonic and optical comb signals; third, polarization management is complex and the system integration is low; and fourth, it has poor adaptability to smooth and rough surfaces. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention proposes an optical coupled detection device and method, which achieves comprehensive detection of multiple parameters at the same location through coaxial optical path, timing control, and polarization optimization.

[0005] To achieve one of the above-mentioned objectives, one embodiment of the present invention provides an optical coupling detection device, comprising: a light source module including a first laser source for generating continuous laser light and a second laser source for generating pulsed laser light; an optical path coupling and control module configured to: divide the continuous laser light into three paths and process them into a local oscillator optical comb, a signal optical comb, and an ultrasonic detection laser, respectively; combine the signal optical comb, the ultrasonic detection laser, and the pulsed laser light and focus them on the same test point of the sample; and separate the reflected beam from the sample into different optical paths for output to corresponding detection units; and a detection module including a detection module for receiving the local oscillator optical comb and the signal optical comb reflected from the sample. The system includes a first detection unit for extracting interference signals, a second detection unit for receiving ultrasonic detection laser reflected from the sample to obtain ultrasonic signals, and a third detection unit for obtaining laser-induced breakdown spectral signals generated by the sample; a signal processing module including a first signal processing system for receiving and processing the output signals of the first detection unit, a second signal processing system for receiving and processing the output signals of the second detection unit, and a third signal processing system for receiving and processing the output signals of the third detection unit; and a synchronization control module for controlling the emission times of the pulsed laser and the continuous laser, as well as the processing sequence of each signal processing system, to avoid timing interference between signals.

[0006] Furthermore, the optical path coupling and control module includes: a beam combining and separating unit, used to combine the signal optical comb and the ultrasonic detection laser into a coaxial mixed incident beam, and to separate the mixed reflected beam returning from the sample into different optical paths, wherein the mixed reflected beam is a reflected signal optical comb and a reflected ultrasonic detection laser; and a wavelength combining unit, used to combine the mixed incident beam and the pulsed laser and focus them on the same test point of the sample.

[0007] Further, the beam combining and separating unit includes, sequentially arranged along the incident light path: a polarization component for adjusting three continuous laser beams to a first polarization state, a second polarization state, and a third polarization state, respectively, wherein one of the two continuous laser beams adjusted to the first polarization state is used to generate the local oscillator optical comb, and the other is used as the ultrasonic detection laser; and the one continuous laser beam adjusted to the second polarization state is used to generate the signal optical comb; a polarization combining unit for combining the signal optical comb in the second polarization state and the ultrasonic detection laser in the first polarization state into a mixed incident beam; a light path separating unit for transmitting the mixed incident beam to the sample surface and spatially separating the mixed reflected beam returning from the sample surface from the mixed incident beam; and a polarization state adjustment unit for deflecting the polarization state angle of the mixed incident beam received from the light path separating unit by 45°, and deflecting the polarization state angle of the mixed reflected beam returning from the sample surface by another 45° before returning it to the light path separating unit.

[0008] Furthermore, the beam combining and separating unit further includes a polarization beam splitting unit, used to separate the mixed reflected beam received from the optical path separating unit into a first polarization state reflected beam and a second polarization state reflected beam according to the polarization state, wherein the first polarization state reflected beam is a signal optical comb reflected back from the sample, and the second polarization state reflected beam is an ultrasonic detection laser reflected back from the sample.

[0009] Furthermore, the wavelength beam combining unit is located at the intersection of the mixed incident beam and the pulsed laser, and is used to transmit the mixed incident beam received from the polarization state adjustment unit and reflect the pulsed laser, so that the two beams are combined into a coaxial beam and focused on the test point of the sample.

[0010] Furthermore, the optical path coupling and control module further includes a pulse optical path coupling unit, which is disposed on the optical path between the second laser source and the wavelength beam combining unit, for processing the pulsed laser into a focused beam that can be coaxially combined with the mixed incident beam.

[0011] Furthermore, the optical path separation unit employs an optical circulator, and the polarization state adjustment unit employs a λ / 4 waveplate.

[0012] Furthermore, the wavelength combining unit employs a dichroic mirror.

[0013] Further, the first detection unit includes: an optical interference beam splitter subunit, used to receive the local oscillator optical comb of the first polarization state and the first polarization state reflected beam separated from the polarization beam splitter, and to combine and interfere the first polarization state reflected beam with the local oscillator optical comb of the first polarization state to generate two interference light signals; a balanced detection subunit, connected to the optical interference beam splitter subunit, to perform differential detection on the two output interference light signals; the second detection unit includes: an interference demodulation subunit, used to receive the second polarization state reflected beam separated from the polarization beam splitter, and The phase change caused by ultrasound carried in the second polarized reflected beam is converted into a light intensity change; a photoelectric conversion subunit, connected to the interference demodulation subunit, is used to convert the light intensity change into an electrical signal; and the third detection unit includes: a spectral acquisition subunit, used to acquire the plasma signal generated by laser-induced breakdown, i.e., the laser-induced breakdown spectral signal; a dispersion subunit, optically connected to the spectral acquisition subunit, used to disperse the plasma signal according to wavelength; and a photoelectric conversion subunit, optically connected to the dispersion subunit, used to convert the dispersed spectral signal into an electrical signal.

[0014] Furthermore, the synchronization control module is configured to: set the optical comb measurement period and the pulse excitation period; control the first signal processing system to work during the optical comb measurement period; control the second laser source to emit pulsed laser light during the pulse excitation period; and control the third signal processing system and the second signal processing system to work in a time-sharing manner during different delay times after the pulsed laser light emission, so as to avoid timing interference between signals.

[0015] Furthermore, the synchronization control module controls the emission timing of the pulsed laser and the continuous laser, as well as the processing sequence of each signal processing system, specifically including: during the optical comb measurement cycle, the synchronization control module controls only the first signal processing system to operate, so that the first signal processing system acquires sample surface morphology information based on the output signal of the first detection unit; during the pulse excitation cycle, the synchronization control module first controls the second laser source to emit a pulsed laser; then, during a first delay time after the pulsed laser emission, it controls only the third signal processing system to operate, so as to extract sample composition information based on the output signal of the third detection unit; and during a second delay time after the pulsed laser emission, it controls only the second signal processing system to operate, so as to extract sample thickness and defect information based on the output signal of the second detection unit; wherein, the synchronization control module controls the first laser source to continuously emit the continuous laser during the optical comb measurement cycle and the pulse excitation cycle.

[0016] Furthermore, the device also includes a multimodal data fusion module, which receives the processed information from each signal processing system and performs spatial alignment and feature-level fusion on the three types of information received from each signal processing system to output a comprehensive detection result of the sample's morphology, composition, thickness, and defect distribution.

[0017] An embodiment of the present invention also provides an optical coupling detection method, which uses the optical coupling detection device described above. The method includes the following steps: S1: Adjusting the position of the sample to be tested by a displacement stage, so that the signal comb, the ultrasonic detection laser, and the pulsed laser are combined and focused on the test point of the sample, wherein the displacement stage is used to place the sample to be tested; S2: The synchronization control module controls the first laser source to continuously emit a continuous laser; S3: During the comb measurement cycle, the synchronization control module controls only the first signal processing system to work, so that the first signal processing system acquires the morphological information of the sample based on the output signal of the first detection unit; S4: During the pulse excitation cycle, the synchronization control module first controls the second laser source to emit a pulsed laser; then, during a first delay time after the pulsed laser is emitted, controls only the third signal processing system to work, so as to extract the composition information of the sample based on the output signal of the third detection unit; and during a second delay time after the pulsed laser is emitted, controls only the second signal processing system to work, so as to extract the thickness and defect information of the sample based on the output signal of the second detection unit.

[0018] The beneficial effects of this invention are as follows: This invention combines the signal optical comb, ultrasonic detection laser and pulsed laser into the same micro-region of the sample through the optical path coupling and control module; and coordinates the timing through the synchronization control module to avoid signal interference, thereby realizing the comprehensive detection of composition, morphology, thickness and defects at the same location. Attached Figure Description

[0019] Figure 1 This is an overall framework diagram of the optical coupled detection device of the present invention;

[0020] Figure 2 This is a detailed structural diagram of the optical coupled detection device of the present invention; Figure 3 This is a signal flow block diagram of the optical coupled detection device of the present invention; Figure 4 This is a flowchart of the optical coupling detection method of the present invention.

[0021] Reference numerals: 10-Light source module, 11-First laser source, 12-Second laser source, 20-Optical path coupling and control module, 30-Detection module, 31-First detection unit, 32-Second detection unit, 33-Third detection unit, 40-Signal processing module, 41-First signal processing system, 42-Second signal processing system, 43-Third signal processing system, 50-Synchronization control module, 60-Multimodal data fusion module, 201-1×3 fiber coupler, 202-Fiber polarization combiner, 203-Optical circulator, 204-λ / 4 waveplate, 205-Dialect mirror, 206-Fiber polarization splitter. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below in conjunction with specific embodiments and corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0023] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0024] In one embodiment, the present invention provides an optical coupling detection device (dual optical comb). LIBS Laser-ultrasound combined detection device). (e.g., Figure 1As shown, the optical coupling detection device of the present invention includes: a light source module 10, which includes a first laser source 11 for generating continuous laser light and a second laser source 12 for generating pulsed laser light; an optical path coupling and control module 20, configured to: divide the continuous laser light into three paths and process them into a local oscillator optical comb, a signal optical comb, and an ultrasonic detection laser, respectively; combine the signal optical comb, the ultrasonic detection laser, and the pulsed laser light and focus them on the same test point of the sample under test; and separate the reflected beam from the sample under test into different optical paths for output to corresponding detection units; and a detection module 30, including a first detection unit for receiving the local oscillator optical comb and the signal optical comb reflected from the sample to extract interference signals. The system comprises: a first detection unit 31 for receiving ultrasonic detection laser reflected from the sample to obtain ultrasonic signals; a second detection unit 32 for obtaining laser-induced breakdown spectral signals generated by the sample; a signal processing module 40 including a first signal processing system 41 for receiving and processing the output signals of the first detection unit, a second signal processing system 42 for receiving and processing the output signals of the second detection unit, and a third signal processing system 43 for receiving and processing the output signals of the third detection unit; and a synchronization control module 50 for controlling the emission times of the pulsed laser and the continuous laser, as well as the processing sequence of each signal processing system, to avoid timing interference between signals.

[0025] The above technical solution enables the signal optical comb, ultrasonic detection laser and pulsed laser to be combined into the same micro-area of ​​the sample through the optical path coupling and control module 20; and the timing is coordinated by the synchronization control module 50 to avoid signal interference, thereby realizing the comprehensive detection of composition, morphology, thickness and defects at the same location.

[0026] In a specific embodiment, such as Figure 2 As shown, the first laser source 11 is a long-wavelength continuous laser, and the second laser source 12 is a short-wavelength pulsed laser. The pulsed excitation laser is a short-wavelength laser in the ultraviolet to green range (e.g., a 532nm pulsed laser), and the continuous laser is a long-wavelength infrared laser (e.g., a 1550nm continuous laser) to avoid interference between the excitation laser and the detection laser.

[0027] To combine and focus the signal optical comb, ultrasonic detection laser, and pulsed laser onto the same test point of the sample, thereby achieving joint detection by dual optical combs, laser ultrasound, and LIBS, the optical path coupling and control module includes: a beam combining and separating unit, used to combine the signal optical comb and the ultrasonic detection laser into a coaxial mixed incident beam, and to separate the mixed reflected beam returning from the sample, i.e., the reflected signal optical comb and the reflected ultrasonic detection laser, into different optical paths; and a wavelength combining unit, used to combine the mixed incident beam and the pulsed laser and focus them onto the same test point of the sample.

[0028] To achieve coaxial beam combining of the signal optical comb and laser ultrasound, the beam combining and separating unit includes, sequentially arranged along the incident optical path: a polarization component for adjusting three continuous laser beams to a first polarization state, a second polarization state, and a third polarization state, respectively, wherein one of the two continuous laser beams adjusted to the first polarization state is used to generate the local oscillator optical comb, and the other is used as the ultrasound detection laser; and one continuous laser beam adjusted to the second polarization state is used to generate the signal optical comb; a polarization beam combining unit for combining the signal optical comb in the second polarization state and the ultrasound detection laser in the first polarization state into a mixed incident beam; and an optical path separating unit for transmitting the mixed incident beam to the sample surface and spatially separating the mixed reflected beam returning from the sample surface from the mixed incident beam.

[0029] See Figure 2 The continuous laser generated by the first laser source 11 is split into three paths by a laser beam splitting unit, which are used to generate a local oscillator optical comb with a first polarization state, a signal optical comb with a second polarization state, and an ultrasonic detection laser with a first polarization state, respectively. In a specific embodiment, for example, a 1×3 fiber coupler 201 can be used to split the continuous laser generated by the first laser source into three paths, and the polarization states of the first and second continuous laser paths are adjusted to S-state (i.e., the first polarization state) and P-state (i.e., the second polarization state) respectively by corresponding polarization components (polarization controllers 1 and 2), and further, an S-state local oscillator optical comb and a P-state signal optical comb are generated by corresponding electro-optic modulation units (electro-optic modulators 1 and 2). In addition, the polarization state of the third continuous laser path is adjusted to S-state by a corresponding polarization component (polarization controller 3) as the ultrasonic detection laser. Of course, it is understandable that... Figure 2 The P state can be replaced by the S state, and the S state can be replaced by the P state, as long as the orthogonality requirement of the corresponding polarization state is met.

[0030] The polarization combining unit uses an optical fiber polarization combiner 202, such as... Figure 2 As shown, the P-state signal optical comb and the S-state ultrasonic detection laser are combined into a mixed incident beam by the fiber polarization combiner 202. In a specific embodiment, to facilitate the two beams to be combined at the polarization combining unit, a 45° reflector can be further provided to change the propagation direction of the S-state ultrasonic detection laser, enabling it to enter the fiber polarization combiner 202 and be combined with the signal optical comb.

[0031] To achieve spatial separation of the incident light beam and the light beam returning from the sample, thus isolating the transmitting and receiving optical paths, an optical path separation unit is further provided. This unit transmits the mixed incident light beam (P-state signal comb and S-state ultrasonic detection laser) to the sample surface and spatially separates the mixed reflected light beam returning from the sample surface from the mixed incident light beam. In a specific embodiment, the optical path separation unit can employ, for example... Figure 2The optical circulator 203 shown is used to change the exit direction of the mixed reflected beam, thereby separating the incident beam and the reflected beam. The incident beam enters through port a and exits through port b, while the returning reflected beam enters through port b and exits through port c, thus changing the exit direction of the returning beam.

[0032] Furthermore, the beam combining and separating unit of the present invention also includes a polarization state adjustment unit, used to deflect the polarization state angle of the mixed incident beam received from the optical path separating unit by 45°, and to deflect the polarization state angle of the mixed reflected beam returning from the sample by another 45° before returning it to the optical path separating unit. This achieves orthogonal polarization state reversal after the beam travels back and forth twice (i.e., the P-state signal comb, after being reflected back from the sample, is adjusted to the S-state after passing through a λ / 4 waveplate again; the S-state ultrasonic detection laser, after being reflected back from the sample, is adjusted to the P-state after passing through a λ / 4 waveplate again). This ensures precise separation and non-crosstalk between the signal comb and the ultrasonic detection laser in the subsequent polarization beam splitting unit, while simultaneously guaranteeing co-point incidence on the sample surface. In a specific embodiment, the polarization state adjustment unit can employ, for example... Figure 2 The λ / 4 waveplate 204 is shown.

[0033] Because the optical comb detection and laser ultrasonic detection are designed with the same optical path, the mixed beam returning from the sample contains both S-state reflected signal optical comb and P-state reflected laser signal. To achieve separation of the two, a polarization beam splitter unit is further set up, for example, Figure 2 The fiber polarization beam splitter 206 shown separates the mixed reflected beam received from the optical path separation unit into an S-state reflected signal optical comb (first polarization reflected beam) and a P-state reflected laser signal (second polarization reflected beam) according to the polarization state, thereby providing different reflected signal inputs for different subsequent detection units.

[0034] As described above, in order to achieve synchronous detection of LIBS, the light source module of the present invention further includes a second laser source 12 for emitting pulsed laser. To combine the pulsed laser with the mixed incident beam (P-state signal comb + S-state ultrasonic detection laser) into a coaxial beam for transmission along the same optical path, a wavelength combining unit is further provided at the intersection of the mixed incident beam and the pulsed laser (for example, a wavelength combining unit can be used). Figure 2 The dichroic mirror 205 is used to transmit the mixed incident beam and reflect the pulsed laser, so that the two beams are combined into a coaxial beam and focused on the test point of the sample. In order to process the pulsed laser into a focused beam that can be coaxially combined with the mixed incident beam, a pulse optical path coupling unit is further set in the optical path between the pulsed laser and the wavelength combining unit.

[0035] In a specific embodiment, see, for example, [link to relevant documentation]. Figure 2The pulsed optical path coupling unit may include a beam expander, a focusing mirror, and a 45° reflecting mirror to shape, focus, and directionally change the pulsed laser beam, so that it is coaxially combined with the mixed incident beam and focused on the same test point of the sample.

[0036] To acquire different signals, the detection module of the present invention includes a first detection unit for receiving the local oscillator optical comb and the signal optical comb reflected from the sample to extract interference signals, a second detection unit for receiving the ultrasonic detection laser reflected from the sample to obtain ultrasonic signals, and a third detection unit for acquiring the laser-induced breakdown spectrum signal generated by the sample.

[0037] The first detection unit includes: an optical interference beam splitter subunit, used to receive the local oscillator optical comb of the first polarization state and the reflected beam of the first polarization state separated from the polarization beam splitter, and to combine and interfere the reflected beam of the first polarization state with the local oscillator optical comb of the first polarization state to generate two interference optical signals; and a balanced detection subunit, connected to the optical interference beam splitter subunit, to perform differential detection on the two output interference optical signals.

[0038] See Figure 2 The optical interference beam splitter can employ a 2×2 fiber coupler to combine and interfere with the S-state local oscillator optical comb and the S-state reflected signal optical comb received from the fiber polarization beam splitter, generating two interference optical signals. The two split optical signals are then respectively detected by a balanced detector subunit (e.g., Figure 2 The balanced detection system (shown) uses two matched photodetectors to receive signals, and the two output electrical signals are connected to a differential amplifier to achieve common-mode noise suppression and linear extraction of the interference signal. Further, the balanced detection system outputs the interference signal to a first signal processing system 41 to generate three-dimensional point cloud coordinates, thereby extracting the sample's morphological information. Specifically, the first signal processing system 41 performs the following processing: by constructing a trajectory matrix and performing singular value decomposition (SSA) analysis, the signal and noise are separated and reconstructed; and a dispersive element is used to map the optical frequency domain interference into a time domain signal to achieve high-precision measurement of the absolute distance; finally, after converting the ranging data to global coordinates, voxel grid downsampling is used to compress the point cloud data volume.

[0039] The second detection unit of the present invention includes: an interference demodulation subunit, used to receive the second polarization-state reflected beam separated by the polarization beam splitter, and convert the phase change carried in the second polarization-state reflected beam caused by ultrasound into a light intensity change; and a photoelectric conversion subunit, connected to the interference demodulation subunit, used to convert the light intensity change into an electrical signal.

[0040] See Figure 2The interferometric demodulation subunit can employ a laser interferometer, such as a CFPI / TWM (confocal Fabry-Perot interferometer), to convert the phase change of the reflected light signal carrying ultrasonic information into a light intensity change, thereby detecting minute vibrations on the sample surface. The light signal output from the CFPI / TWM is further processed by a photoelectric conversion subunit (e.g., Figure 2 The photodetector shown converts the signal into an electrical signal for preprocessing by the second signal processing system 42 to extract the thickness and defect information of the sample. Specifically, the second signal processing system 42 can perform the following preprocessing: using wavelet decomposition and an adaptive threshold based on median absolute deviation (MAD) to effectively suppress noise and retain the defect signal; constructing an overcomplete dictionary and using an iterative thresholding algorithm to sparsely reconstruct the defect echo component from the noisy signal; and reducing the number of scanning points through compressed sensing technology and performing synthetic aperture focusing (SAFT) post-processing to achieve high-resolution imaging.

[0041] The third detection unit of the present invention includes: a spectral acquisition subunit for acquiring plasma signals generated by laser-induced breakdown, i.e., laser-induced breakdown spectral signals; a dispersion subunit optically connected to the spectral acquisition subunit for dispersing the plasma signals according to wavelength; and a photoelectric conversion subunit optically connected to the dispersion subunit for converting the dispersed spectral signals into electrical signals.

[0042] See Figure 2 The spectral acquisition subunit can use a 45° fiber optic probe (10-15 mm from the sample) to collect plasma and transmit it to the subsequent dispersive subunit (e.g., Figure 2 The spectrometer shown disperses the light according to wavelength, and then the light is transmitted through a photoelectric conversion subunit (e.g., Figure 2 The charge-coupled device (CCD) shown converts the dispersed spectral signal into an electrical signal for preprocessing by the third signal processing system 43 to extract the sample's compositional information. Specifically, the third signal processing system 43 can perform the following preprocessing: spectral denoising using Savitzky-Golay smoothing filtering; robust estimation and subtraction of the continuous background of the spectrum using asymmetric weighted least squares (AsLS); precise peak location using a Voigt line shape model and a dual-scale window sliding peak finding method; and centering each spectrum and dividing by the standard deviation to eliminate differences in intensity dimensions.

[0043] It should be noted that the specific processing methods of the first, second and third signal processing systems are all conventional techniques in the field and are not key improvements of this invention, so they will not be described in detail here.

[0044] In a further implementation, such as Figure 1 and Figure 2 As shown, the optical coupled detection device of the present invention may further include a multimodal data fusion module 60, which is connected to each signal processing system to receive the corresponding processed information from each signal processing system, and to perform spatial alignment and feature-level fusion on the three types of information received from each signal processing system to output a comprehensive detection result of the sample's morphology, composition, thickness, and defect distribution. Specifically, the multimodal data fusion module 60 can achieve hardware benchmark unification by sharing a high-precision three-dimensional displacement stage, and uses the Iterative Closest Point (ICP) algorithm to accurately register the dual-comb morphology, LIBS element distribution, and laser-ultrasonic defect map in space; it extracts three-dimensional contour features from the dual-comb data, extracts element fingerprints from the LIBS spectrum through principal component analysis (PCA) or standard normal variable transformation (SNV), and extracts features such as defect echo and sound velocity from the laser-ultrasonic signal through wavelet transform or empirical mode decomposition (EMD).

[0045] It should be noted that the specific processing method of the multimodal data fusion module 60 is a conventional technical means in this field and is not a key improvement point of this invention, so it will not be described in detail here.

[0046] As described above, in order to avoid timing interference between laser-induced plasma signals, laser ultrasonic signals and optical comb detection signals, and to ensure that the signals of the three modes are acquired in a time-division manner within the same detection cycle and do not overlap, the emission time of pulsed laser and continuous laser and the processing timing of each signal processing system are controlled by the synchronization control module 50 (e.g., synchronization controller).

[0047] The synchronization control module of the present invention is configured to: set the optical comb measurement period and the pulse excitation period; control the first signal processing system to work during the optical comb measurement period; control the second laser source to emit pulsed laser during the pulse excitation period; and control the third signal processing system and the second signal processing system to work in a time-sharing manner during different delay times after the pulsed laser emission, so as to avoid timing interference between signals.

[0048] Specifically, the same detection cycle can be divided into an optical comb measurement cycle and a pulse excitation cycle.

[0049] During the optical comb measurement cycle, the optical comb measures the beam, and the synchronous control module controls only the first signal processing system to work, so that the first signal processing system can acquire sample surface morphology information based on the output signal of the first detection unit.

[0050] During the pulse excitation cycle, the synchronization control module first controls the second laser source to emit a pulsed laser, which simultaneously excites the laser-induced breakdown spectrum signal and the laser ultrasonic signal of the sample. Then, during the first delay time after the pulsed laser is emitted, the module controls only the third signal processing system to work, so as to extract the composition information of the sample based on the output signal of the third detection unit. During the second delay time after the pulsed laser is emitted, the module controls only the second signal processing system to work, so as to extract the thickness and defect information of the sample based on the output signal of the second detection unit.

[0051] The synchronization control module controls the first laser source to continuously emit laser light during the optical comb measurement cycle and the pulse excitation cycle.

[0052] By controlling the operation of the first signal processing system during the optical comb measurement cycle, the reflected signal optical comb can be detected, thereby obtaining the morphological information of the sample. By controlling the operation of the third signal processing system within a first delay time (e.g., 0.5 μs to 1 μs), plasma can be collected and detected, thereby obtaining the compositional information of the sample. By controlling the operation of the second signal processing system within a second delay time (e.g., 1 μs to 50 μs), interference from plasma on the laser ultrasonic signal is avoided, enabling the detection of the laser ultrasonic signal and thus obtaining the thickness and defect information of the sample.

[0053] The synchronization control module and the multimodal data fusion module can be implemented using separate controllers / processors, or they can be built into the computer as functional modules of the computer.

[0054] In a further implementation, such as Figure 2 As shown, the synchronous control module of the present invention is also connected to the displacement stage for placing the sample to be tested, so as to control the displacement stage to adjust the sample to the next test point position after the detection of one test point of the sample is completed, until the detection and scanning of the entire sample (or object to be tested) is completed.

[0055] Figure 3 This is a signal flow block diagram of the optical coupled detection device of the present invention, which shows the signal connection relationship between the continuous laser, pulsed laser, computer and the three detection modules of optical frequency comb (signal optical comb), LIBS and laser ultrasound.

[0056] In another embodiment, the present invention also provides an optical coupling detection method (dual optical comb). LIBS Laser-ultrasound combined detection method). The optical combined detection method of the present invention uses the optical combined detection device as described above, see [link to related document]. Figure 4 The method includes the following steps: S1: The position of the sample to be tested is adjusted by the displacement stage so that the signal optical comb, the ultrasonic detection laser and the pulsed laser are combined and focused on the test point of the sample to be tested, wherein the displacement stage is used to place the sample to be tested; S2: The synchronization control module controls the first laser source to continuously emit continuous laser light; S3: During the optical comb measurement cycle, the synchronization control module controls only the first signal processing system to work, so that the first signal processing system can acquire the morphological information of the sample based on the output signal of the first detection unit; S4: During the pulse excitation cycle, the synchronization control module first controls the second laser source to emit a pulsed laser; then, during the first delay time after the pulsed laser is emitted, it controls only the third signal processing system to work, so as to extract the composition information of the sample based on the output signal of the third detection unit; and during the second delay time after the pulsed laser is emitted, it controls only the second signal processing system to work, so as to extract the thickness and defect information of the sample based on the output signal of the second detection unit.

[0057] Specifically, the first laser source can emit a continuous laser at 1550nm, and the second laser source emits a pulsed laser at 532nm.

[0058] Specifically, the first delay time is 0.5μs to 1μs, and the second delay time is 1μs to 50μs.

[0059] Furthermore, the device also includes a multimodal data fusion module. In step S3, after acquiring the morphology information of the sample, the first signal processing system further transmits it to the multimodal data fusion module. In step S4, after acquiring the composition information of the sample, the third signal processing system further transmits it to the multimodal data fusion module; and after acquiring the thickness and defect information of the sample, the second signal processing system further transmits it to the multimodal data fusion module. After receiving the three types of information, the multimodal data fusion module performs spatial alignment and feature-level fusion to output a comprehensive detection result of the sample's composition, morphology, thickness, and defect distribution.

[0060] In addition, since there are usually multiple test points on a sample, after the detection of one test point is completed, the synchronous control module controls the displacement stage to adjust the sample to the next test point position and repeats steps S1-S4 until the detection of all test point positions (i.e., the entire test sample) is completed.

[0061] The dual optical comb of the present invention LIBS In the laser-ultrasound combined detection device and method, the continuous laser and the signal comb and pulsed laser generated by optical path coupling are combined into the same micro-area of ​​the sample to be tested, and the timing is coordinated by the synchronous control module to avoid signal interference, so as to realize the comprehensive detection of the composition, morphology, thickness and defects of the sample at the same location.

[0062] It should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This way of describing the specification is only for clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

[0063] The detailed descriptions listed above are merely specific descriptions of feasible embodiments of the present invention, and are not intended to limit the scope of protection of the present invention. All equivalent embodiments or modifications made without departing from the spirit of the present invention should be included within the scope of protection of the present invention.

Claims

1. An optical multi-use detection device, characterized by, include: The light source module includes a first laser source for generating continuous laser light and a second laser source for generating pulsed laser light. The optical path coupling and control module is configured to: divide the continuous laser into three paths and process them into a local oscillator optical comb, a signal optical comb, and an ultrasonic detection laser, respectively; combine the signal optical comb, the ultrasonic detection laser, and the pulsed laser and focus them on the same test point of the sample; and separate the reflected beam returning from the sample into different optical paths to output to the corresponding detection units. The detection module includes a first detection unit for receiving the local oscillator optical comb and the signal optical comb reflected back from the sample to extract interference signals, a second detection unit for receiving the ultrasonic detection laser reflected back from the sample to obtain ultrasonic signals, and a third detection unit for obtaining the laser-induced breakdown spectrum signal generated by the sample. The signal processing module includes a first signal processing system for receiving and processing the output signal of the first detection unit, a second signal processing system for receiving and processing the output signal of the second detection unit, and a third signal processing system for receiving and processing the output signal of the third detection unit. A synchronization control module is used to control the emission timing of the pulsed laser and the continuous laser, as well as the processing timing of each signal processing system, so as to avoid timing interference between signals; The optical path coupling and control module includes a beam combining and separating unit, which combines the signal optical comb and the ultrasonic detection laser into a coaxial mixed incident beam and separates the mixed reflected beam returning from the sample into different optical paths, wherein the mixed reflected beam is a reflected signal optical comb and a reflected ultrasonic detection laser. The beam combining and separating unit includes: A polarization component is used to adjust three continuous laser beams to a first polarization state, a second polarization state, and a third polarization state, respectively. One of the two continuous laser beams adjusted to the first polarization state is used to generate the local oscillator optical comb, and the other is used as the ultrasonic detection laser. The one continuous laser beam adjusted to the second polarization state is used to generate the signal optical comb. A polarization beam combiner unit is used to combine the signal optical comb in the second polarization state with the ultrasonic detection laser in the first polarization state into a mixed incident beam; An optical path separation unit is used to transmit the mixed incident beam to the sample surface and spatially separate the mixed reflected beam returning from the sample surface from the mixed incident beam; and The polarization state adjustment unit is used to deflect the polarization state angle of the mixed incident beam received from the optical path separation unit by 45°, and to deflect the polarization state angle of the mixed reflected beam returning from the sample surface by another 45° before returning it to the optical path separation unit. A polarization beam splitter is used to separate the mixed reflected beam received from the optical path separation unit into a first polarization reflected beam and a second polarization reflected beam according to the polarization state. The first polarization reflected beam is a signal optical comb reflected back from the sample, and the second polarization reflected beam is an ultrasonic detection laser reflected back from the sample.

2. The apparatus of claim 1, wherein, The optical path coupling and control module further includes a wavelength beam combining unit, used to combine the mixed incident beam and the pulsed laser beam and focus them on the same test point of the sample under test.

3. The apparatus of claim 2, wherein, The wavelength beam combining unit is located at the intersection of the mixed incident beam and the pulsed laser. It is used to transmit the mixed incident beam received from the polarization state adjustment unit and reflect the pulsed laser, so that the two beams are combined into a coaxial beam and focused on the test point of the sample.

4. The apparatus of claim 3, wherein, The optical path coupling and control module further includes a pulse optical path coupling unit, which is disposed on the optical path between the second laser source and the wavelength beam combining unit, for processing the pulsed laser into a focused beam that can be coaxially combined with the mixed incident beam.

5. The apparatus of claim 1, wherein, The optical path separation unit uses an optical circulator, and the polarization state adjustment unit uses a λ / 4 waveplate.

6. The apparatus of claim 3, wherein, The wavelength combining unit uses a dichroic mirror.

7. The apparatus of any one of claims 1-6, wherein, The first detection unit includes: The optical interference beam splitter is used to receive the local oscillator optical comb of the first polarization state and the first polarization state reflected beam separated from the polarization beam splitter, and to combine and interfere the first polarization state reflected beam with the local oscillator optical comb of the first polarization state to generate two interference optical signals. A balanced detection subunit is connected to the optical interference beam splitter subunit to perform differential detection on the two output interference optical signals; The second detection unit includes: An interference demodulation subunit is used to receive the second polarization-state reflected beam separated by the polarization beam splitter unit, and to convert the phase change caused by ultrasound carried in the second polarization-state reflected beam into a light intensity change; A photoelectric conversion subunit, connected to the interference demodulation subunit, is used to convert changes in light intensity into electrical signals; and The third detection unit includes: The spectral acquisition subunit is used to acquire the plasma signal generated by laser-induced breakdown, that is, the laser-induced breakdown spectral signal; The dispersion subunit is optically connected to the spectral acquisition subunit and is used to disperse the plasma signal according to wavelength. The photoelectric conversion subunit is optically connected to the dispersion subunit and is used to convert the dispersed spectral signal into an electrical signal.

8. The apparatus of claim 1, wherein, The synchronization control module is configured to: set the optical comb measurement period and the pulse excitation period; control the first signal processing system to work during the optical comb measurement period; control the second laser source to emit pulsed laser during the pulse excitation period; and control the third signal processing system and the second signal processing system to work in a time-sharing manner at different delay times after the pulsed laser emission, so as to avoid timing interference between signals.

9. The apparatus of claim 8, wherein, The synchronization control module controls the emission timing of the pulsed laser and the continuous laser, as well as the processing sequence of each signal processing system, specifically including: During the optical comb measurement cycle, the synchronization control module controls the first signal processing system to work, so that the first signal processing system can acquire sample surface morphology information based on the output signal of the first detection unit; During the pulse excitation cycle, the synchronization control module first controls the second laser source to emit a pulsed laser; then, within a first delay time after the pulsed laser emission, it controls the third signal processing system to operate, extracting the sample's compositional information based on the output signal of the third detection unit; and within a second delay time after the pulsed laser emission, it controls the second signal processing system to operate, extracting the sample's thickness and defect information based on the output signal of the second detection unit; wherein... The synchronization control module controls the first laser source to continuously emit the continuous laser during the optical comb measurement cycle and the pulse excitation cycle.

10. The apparatus of claim 1, wherein, The device further includes: The multimodal data fusion module is connected to each signal processing system. It receives the processed information from each system and performs spatial alignment and feature-level fusion on the received three types of information to output a comprehensive detection result of the sample's morphology, composition, thickness, and defect distribution.

11. An optical multi-assay detection method, characterized by, Using the optical coupled detection apparatus as described in any one of claims 1-10, the method comprises the following steps: S1: The position of the sample to be tested is adjusted by the displacement stage so that the signal optical comb, the ultrasonic detection laser and the pulsed laser are combined and focused on the test point of the sample to be tested, wherein the displacement stage is used to place the sample to be tested; S2: The synchronization control module controls the first laser source to continuously emit continuous laser light; S3: During the optical comb measurement cycle, the synchronization control module controls the first signal processing system to work so that the first signal processing system can acquire the morphological information of the sample based on the output signal of the first detection unit; S4: During the pulse excitation cycle, the synchronization control module first controls the second laser source to emit a pulsed laser; then, during the first delay time after the pulsed laser is emitted, it controls the third signal processing system to work, so as to extract the composition information of the sample based on the output signal of the third detection unit; and during the second delay time after the pulsed laser is emitted, it controls the second signal processing system to work, so as to extract the thickness and defect information of the sample based on the output signal of the second detection unit.

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