Dynamic surface scanning Raman imaging system and spectral data acquisition method

Abstract

The invention relates to the technical field of spectral analysis and microscopic imaging, and discloses a dynamic surface scanning Raman imaging system and a spectral data acquisition method, and the system comprises a light beam output module which is used for outputting a collimated laser beam; the device comprises a spatial light modulator, an excitation light path module, a sample stage, a collection light path module, an imaging spectrometer and a control module, the control module generates a corresponding driving signal according to a preset image sequence, and the preset image sequence comprises a plurality of preset excitation images arranged according to a set sequence; controlling a spatial light modulator to generate a corresponding dynamic structure light field through a driving signal, obtaining Raman spectrum data of a plurality of excitation light field distribution diagrams through an imaging spectrometer, and reconstructing and decoupling the Raman spectrum data to obtain Raman imaging cube data. Complete Raman imaging cube data can be reconstructed through a small amount of pattern switching and exposure, and the spectrum acquisition efficiency is greatly improved.

Description

Technical Field

[0001] This invention relates to the field of spectral analysis and microscopic imaging technology, specifically to a dynamic surface scanning Raman imaging system and a method for acquiring spectral data. Background Technology

[0002] Currently, Raman imaging technology mainly employs a point-scanning method. Its typical system structure is as follows: a focused laser beam illuminates a point on the sample, exciting a Raman scattering signal at that point; the scattered light is dispersed by a spectrometer, and the complete Raman spectrum of that point is recorded by a detector (such as a CCD); then, the sample is mechanically moved using a two-dimensional translation stage, or a galvanometer is used to deflect the laser focus, scanning the entire test area point by point; finally, the spectral data from each point are stitched together to form an image of the chemical composition distribution.

[0003] Because it strictly follows the "point-by-point excitation-probe" mode, to obtain an image with high spectral dimensions (e.g., 500×500 pixels, each pixel containing 1000 spectral channels), it is necessary to collect 250,000 spectra, which takes a very long time (usually several hours or even longer), and the acquisition efficiency is extremely low. Summary of the Invention

[0004] This invention provides a dynamic surface scanning Raman imaging system and a method for acquiring spectral data, in order to solve the technical problem of low efficiency in Raman spectral data acquisition.

[0005] In a first aspect, the present invention provides a dynamic surface scanning Raman imaging system, comprising:

[0006] Beam output module, used to output collimated laser beam; A spatial light modulator is used to modulate a collimated laser beam into a dynamic structured light field corresponding to a preset excitation image; The excitation optical path module is used to image the dynamic structured light field onto the surface of the sample under test on the sample stage, forming an excitation light field distribution map corresponding to the preset excitation image. The sample stage is used to hold the sample to be tested. The optical path module is used to collect the Raman scattered light generated by the sample under test irradiated by the dynamic structured light field; An imaging spectrometer is used to receive Raman scattered light and obtain Raman spectral data corresponding to the excitation light field distribution map based on the Raman scattered light. The control module is used to generate corresponding driving signals according to a preset image sequence. The preset image sequence includes multiple preset excitation images arranged in a set order. The driving signals control the spatial light modulator to generate corresponding dynamic structured light fields. The Raman spectral data of multiple excitation light field distribution maps are acquired by the imaging spectrometer. The multiple Raman spectral data are reconstructed and decoupled to obtain Raman imaging cube data.

[0007] In one optional embodiment, the imaging spectrometer includes a slit, a grating, and a detector arranged sequentially along the incident direction of the light beam. The slit is used to image the Raman scattered light along the spatial dimension, the grating is used to disperse the Raman scattered light distributed along the spatial dimension and expand it along the spectral dimension, and the detector is used to acquire Raman spectral data of the expanded Raman spectrum.

[0008] In one alternative implementation, the beam output module includes a laser and a beam expander and collimator module. The laser is used to generate an initial laser beam, and the beam expander and collimator module is used to expand and collimate the initial laser beam to obtain a collimated laser beam with an aperture that matches the spatial light modulator.

[0009] In one alternative implementation, the excitation optical path module includes one or more lenses for imaging the dynamic structured light field onto the surface of the sample to be tested on the sample stage via a scanning device, thereby forming an excitation light field distribution map.

[0010] In one alternative implementation, the scanning device is a galvanometer.

[0011] In one optional implementation, the optical path module includes a microscope objective and a filter. The microscope objective is used to collect the scattered light generated by the sample under test irradiated by the dynamic structured light field, and the filter is used to filter out Rayleigh scattered light from the scattered light to obtain Raman scattered light.

[0012] In one optional implementation, the preset excitation image is a multifocal array, line focus, speckle field, or structured light field, and the excitation light field distribution map is a focal point array or linear light spot.

[0013] In a second aspect, the present invention provides a method for acquiring spectral data, applicable to the method for acquiring spectral data as described in the first aspect and any one of the claims of the first aspect, comprising: A corresponding driving signal is generated based on a preset image sequence, which includes multiple preset excitation images arranged in a set order. The corresponding dynamic structured light field is generated by controlling the spatial light modulator with a driving signal, and the Raman spectral data of multiple preset excitation images are obtained by an imaging spectrometer. Multiple Raman spectral data were reconstructed and decoupled to obtain Raman imaging cube data.

[0014] The present invention has the following beneficial effects: The dynamic surface scanning Raman imaging system of the present invention generates a dynamic structured light field through a spatial light modulator. The excitation optical path module images the dynamic structured light field onto the surface of the sample under test on the sample stage to form an excitation light field distribution map. The Raman spectral data of multiple excitation light field distribution maps are acquired by an imaging spectrometer. The multiple Raman spectral data are reconstructed and decoupled to obtain Raman imaging cube data. Thus, the system can acquire spectral imaging of the corresponding position of the excitation light field distribution map at one time. The system can acquire Raman spectral information of multiple spatial points in a single exposure. The complete Raman imaging cube data can be reconstructed with a small number of pattern switching and exposures, which greatly improves the spectral acquisition efficiency. Attached Figure Description

[0015] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0016] Figure 1 This is a schematic diagram of the structure of the dynamic surface scanning Raman imaging system according to an embodiment of the present invention; Figure 2 This is a flowchart of the spectral data acquisition method according to an embodiment of the present invention; Explanation of reference numerals in the attached figures: 1. Beam output module; 101. Laser; 102. Beam expander and collimator module; 2. Spatial light modulator; 3. Excitation optical path module; 301. First lens; 302. Second lens; 303. Scanning device; 4. Sample stage; 5. Collection optical path module; 501. Microscope objective; 502. Filter; 6. Imaging spectrometer; 601. Slit; 602. Grating; 603. Detector; 7. Control module. Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0018] It should be noted that the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to the internal connection of two components. The terms "parallel" and "equal" include the described situation and situations that are similar to the described situation, where the range of similarity is within an acceptable deviation range, wherein the acceptable deviation range is determined by a person skilled in the art taking into account the measurement under discussion and the error associated with the measurement of a particular quantity (i.e., the limitations of the measurement system). For example, "parallel" includes absolute parallelism and approximate parallelism, wherein the acceptable deviation range for approximate parallelism can be, for example, a deviation within 5°. "Equal" includes absolute equality and approximate equality, wherein the acceptable deviation range for approximate equality can be, for example, a difference between two equal items less than or equal to 5% of either one. For a person skilled in the art, the specific meaning of the above terms in this application can be understood on a case-by-case basis.

[0019] Currently, Raman imaging technology based on point scanning has the following problems: 1. Low acquisition efficiency; 2. Low light flux: The excitation light energy is highly concentrated on a single diffraction-limited point, and the power density (irradiance) per unit area of ​​the sample is very high, but the total light flux used for imaging is limited, which restricts further improvement of signal intensity and imaging speed; 3. Potential optical damage and thermal effects: For photosensitive samples (such as biological cells and certain polymer materials), high power density focused laser irradiation of the same point for a long time can easily cause photobleaching or thermal damage to the sample, affecting the authenticity of the observation results; 4. High stability requirements: During the long scanning process, the laser source, optical system and mechanical moving parts are required to maintain extremely high stability. Any slight drift will lead to image distortion.

[0020] In view of this, embodiments of the present invention provide a dynamic surface scanning Raman imaging system and a method for acquiring spectral data, which is particularly suitable for scenarios that require rapid and high-throughput acquisition of spatial distribution information of chemical components of substances, such as biomedical detection, materials analysis and drug development.

[0021] To enable those skilled in the art to better understand the present application, the present application will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0022] like Figure 1 As shown, the dynamic surface scanning Raman imaging system of this invention includes: Beam output module 1 is used to output a collimated laser beam; Specifically, the beam output module 1 includes a laser 101 and a beam expander and collimator module 102. The laser 101 is used to generate an initial laser beam, and the beam expander and collimator module 102 is used to expand and collimate the initial laser beam to obtain a collimated laser beam with an aperture that matches the spatial light modulator 2.

[0023] Laser 101 is selected with good monochromaticity and stable power. The initial output laser beam can be a continuous laser or a pulsed laser. The wavelength can be selected according to the characteristics of the sample, such as 532nm, 785nm, 1064nm, etc.

[0024] The beam expander and collimator module 102 employs multiple optical lenses, forming a telescope system, to expand and collimate the initial laser beam emitted from the laser 101, ensuring its aperture matches the modulation surface of the subsequent spatial light modulator 2. By adjusting the initial laser beam output from the laser 101 into a collimated beam with an aperture matching the modulation surface of the spatial light modulator 2, the module ensures efficient utilization of optical energy and uniformity of modulation effect.

[0025] Spatial light modulator 2 is used to modulate the collimated laser beam into a dynamic structured light field corresponding to a preset excitation image; Specifically, the spatial light modulator 2 is an optical device that can adjust the spatial distribution of light waves such as amplitude and phase in real time, and is the core component for realizing dynamic surface scanning in this invention.

[0026] The spatial light modulator 2 is preferably a reflective liquid crystal spatial light modulator 2 or a digital micromirror device. It receives a drive signal from the control module 7 and dynamically loads a series of preset two-dimensional phase or amplitude patterns, i.e., preset excitation images, such as multifocal arrays, line focusing, speckle fields, or structured light fields, onto the modulation surface, thereby modulating the incident collimated laser beam into a corresponding dynamic structured light field.

[0027] Excitation optical path module 3 is used to image the dynamic structured light field onto the surface of the sample to be tested on the sample stage 4, forming an excitation light field distribution map corresponding to the preset excitation image; Specifically, the excitation optical path module 3 includes one or more lenses for imaging the structured light field modulated by the spatial light modulator 2 onto the sample surface on the sample stage 4 via the scanning device 303 or by direct relay imaging, forming a specific excitation light field distribution pattern, such as a focal point array or a linear light spot.

[0028] In one embodiment, the excitation optical path module 3 includes one or more lenses for imaging the dynamic structured light field onto the surface of the sample to be tested on the sample stage 4 through the scanning device 303, forming an excitation light field distribution map.

[0029] In one example, the lens includes a first lens 301 and a second lens 302. The scanning device 303 employs a galvanometer. The first lens 301 and the second lens 302 transmit the dynamic structured light field to the galvanometer and relay the image onto the sample surface on the sample stage 4 through the galvanometer.

[0030] A galvanometer is a high-speed oscillating mirror used to change the propagation direction of a light beam, enabling two-dimensional scanning of the beam on the sample surface. It features fast response speed and high scanning frequency, and can be perfectly synchronized with the high-speed pattern switching of the spatial light modulator 2 and the rapid exposure of the detector 603, further improving the imaging speed of the entire system.

[0031] Sample stage 4 is used to hold the sample to be tested; Specifically, the sample stage 4 is used to hold the sample to be tested. It can be fixed or can be moved in one dimension to achieve large-area splicing.

[0032] The optical path module 5 is used to collect the Raman scattered light generated by the sample under test that has been illuminated by the preset excitation image.

[0033] Specifically, the optical path module 5 includes a microscope objective 501 and a filter 502. The microscope objective 501 is used to collect the scattered light generated by the sample under test irradiated by the dynamic structured light field, and the filter 502 is used to filter out Rayleigh scattered light in the scattered light to obtain Raman scattered light.

[0034] Among them, the microscope objective 501 with a large numerical aperture can efficiently collect Raman scattered light emitted from the sample surface, thereby improving the detection sensitivity of the system.

[0035] The scattered light generated by the sample includes Rayleigh scattering and Raman scattering. Rayleigh scattering is elastically scattered light with the same wavelength as the incident laser and is the main source of noise in Raman spectroscopy measurements. By filtering out the high-intensity Rayleigh scattering light using filter 502, the background noise is greatly reduced, and the signal-to-noise ratio of the Raman spectrum is improved.

[0036] Imaging spectrometer 6 is used to receive Raman scattered light and acquire Raman spectral data corresponding to the excitation light field distribution map based on the Raman scattered light.

[0037] Specifically, the imaging spectrometer includes a slit 601, a grating 602, and a detector 603 arranged sequentially along the incident direction of the light beam. The slit 601 is used to image the Raman scattered light along the spatial dimension, the grating 602 is used to disperse the Raman scattered light distributed along the spatial dimension and expand it along the spectral dimension, and the detector 603 is used to acquire the expanded Raman spectral data.

[0038] The slit 601 is located at the entrance of the imaging spectrometer 6. The final design of the light collection module 5 is to enable the entire excitation light field distribution map that is illuminated on the sample surface to pass through the slit 601 and be clearly imaged along the spatial dimension (Y-axis) on the image plane of the spectrometer, i.e. the detection plane of the detector 603. At the same time, the grating 602 inside the spectrometer disperses the light and expands it along the spectral dimension (X-axis) on the plane of the detector 603.

[0039] The detector 603 is preferably a scientific-grade area array CCD or CMOS detector 603, installed at the image plane position of the imaging spectrometer 6. Its Y-axis direction corresponds to the spatial position information on the sample to be measured, and its X-axis direction corresponds to the Raman spectral information. The readout of the detector 603 is strictly synchronized with the pattern switching of the spatial light modulator 2.

[0040] The control module 7 is used to generate a corresponding driving signal according to a preset image sequence. The preset image sequence includes multiple preset excitation images arranged in a set order. The driving signal controls the spatial light modulator 2 to generate a corresponding dynamic structured light field. The imaging spectrometer 6 acquires Raman spectral data of multiple excitation light field distribution maps. The multiple Raman spectral data are reconstructed and decoupled to obtain Raman imaging cube data.

[0041] Specifically, the preset excitation image is a multifocal array, line focus, speckle field, or structured light field. The multiple excitation light field distribution maps generated by multiple preset excitation images in the preset image sequence illuminating the sample under test can form a complete preset planar region covering the sample under test after being stitched and overlapped.

[0042] Each time, the control module 7 outputs a drive signal to the spatial light modulator 2 based on the preset excitation image. The spatial light modulator 2 generates a dynamic structured light field and forms an excitation light field distribution map corresponding to the preset excitation image on the surface of the sample to be tested. Then, it sends a trigger signal to the detector 603 to control the detector to expose within a specific time window after each excitation light field distribution map has stabilized. The Raman spectral data under the corresponding excitation light field distribution map is collected. Then, the control module 7 controls the spatial light modulator 2 to switch to output the dynamic structured light field corresponding to the next preset excitation image, and collects the Raman spectral data under each excitation light field distribution map in sequence. Finally, the control module 7 reconstructs and decouples the collected Raman spectral data to synthesize complete, high spectral resolution Raman imaging cube data (X, Y, λ).

[0043] This invention also proposes a method for acquiring spectral data, applied to the dynamic surface scanning Raman imaging system described in the above embodiments, such as... Figure 2 As shown, the method includes: Step S201: Generate a corresponding driving signal according to a preset image sequence, wherein the preset image sequence includes multiple preset excitation images arranged in a set order; Step S202: The spatial light modulator 2 is controlled by the driving signal to generate the corresponding dynamic structured light field, and the Raman spectral data of multiple excitation light field distribution maps are acquired by the imaging spectrometer 6. Step S203: Reconstruct and decouple multiple Raman spectral data to obtain Raman imaging cube data.

[0044] In a specific application, the implementation process of the spectral data acquisition method is as follows: 1. System initialization. Set parameters such as laser power, exposure time of detector 603, and gain; load the preset image sequence modulated by spatial light modulator 2 (including multiple preset excitation images, such as N different multifocal arrays or structured light fields) into control module 7.

[0045] 2. Dynamic surface scanning excitation. The control module 7 drives the spatial light modulator 2 to load the first preset excitation image (such as Pattern 1), forming the corresponding first excitation light field distribution map (such as a set of spatially discrete focal points) on the surface of the sample to be tested.

[0046] 3. Synchronous Spectral Imaging. After Pattern 1 stabilizes, control module 7 triggers detector 603 to perform an exposure. At this time, detector 603 receives Raman signals from the entire area of ​​the sample surface illuminated by Pattern 1. On the image plane of detector 603, different rows in the Y direction correspond to different spatial points (Y1, Y2, ...) excited on the sample, while the X direction records the Raman spectrum corresponding to each spatial point.

[0047] 4. Data Reading and Pattern Switching. After the detector 603 completes exposure, it quickly transmits the first frame of spectral image data (DataFrame 1) to the control module 7 for temporary storage. Subsequently, the control module 7 immediately drives the spatial light modulator 2 to switch to the next modulation pattern (Pattern 2).

[0048] 5. Iterative scanning and data acquisition. Repeat steps 2-4 until all N preset excitation images have been traversed and N frames of spectral image data (Data Frame1, 2, ..., N) have been acquired.

[0049] 6. Image Reconstruction and Data Synthesis. The control module 7 utilizes a known preset image sequence and corresponding spectral image data. Through a reconstruction algorithm (such as a deconvolution algorithm based on compressed sensing, or a simple pixel recombination algorithm, depending on the pattern design), it calculates a complete Raman imaging cube with a spatial resolution of M×M pixels (M is much larger than the number of spatial points in a single frame) from N frames of spectral image data. This data cube contains the complete Raman spectrum I(λ) of each pixel (x_i, y_j).

[0050] The dynamic surface scanning Raman imaging system and method of this invention generates a dynamic structured light field through a spatial light modulator 2. The excitation optical path module 3 images the dynamic structured light field onto the surface of the sample to be tested on the sample stage 4 to form a preset excitation image. The Raman spectral data of multiple preset excitation images are acquired by an imaging spectrometer 6. The multiple Raman spectral data are reconstructed and decoupled to obtain Raman imaging cube data. Thus, the system can acquire the spectral imaging of the corresponding position of the preset excitation image at one time. The system can acquire Raman spectral information of multiple spatial points in a single exposure. The complete Raman imaging cube data can be reconstructed with a small number of pattern switching and exposures, which greatly improves the spectral acquisition efficiency.

[0051] By transforming "point-by-point scanning" into "pattern parallel scanning," spectral information from tens to hundreds of spatial points can be acquired in a single exposure. The time required to complete a Raman image with the same spatial and spectral resolution is reduced from several hours using traditional techniques to several minutes or even seconds, increasing acquisition efficiency by tens to hundreds of times and achieving an order-of-magnitude improvement in spectral acquisition efficiency, thus realizing truly fast and high-throughput Raman imaging.

[0052] By dispersing light energy over a larger area of ​​the sample using spatial light modulator 2, the instantaneous power density per unit area of ​​the sample is significantly reduced. This greatly mitigates the photobleaching and thermal damage effects on photosensitive samples, making them more suitable for long-term observation of fragile samples such as living biological cells and tissues.

[0053] The entire data acquisition process is completed in a very short time. By using the electronically controlled modulation switching of the spatial light modulator 2 to switch the preset excitation image, there is no need for complex two-dimensional mechanical scanning, which reduces the risk of image distortion caused by mechanical drift and environmental vibration, making the system more stable and reliable.

[0054] By making full use of the parallel detection capabilities of the laser power and the 603 detector, the total light flux is greater, which is beneficial for obtaining a higher signal-to-noise ratio under low-power illumination or further shortening the imaging time.

[0055] By flexibly programming the spatial light modulator 2 to load patterns, it is easy to switch between imaging modes with different resolutions and different fields of view, and it is compatible with advanced algorithms such as compressed sensing. While ensuring image quality, it can further reduce the number of acquisitions required and achieve ultra-fast imaging.

[0056] This invention also proposes a method for acquiring spectral data, applied to the dynamic surface scanning Raman imaging system described in the above embodiments, such as... Figure 2 As shown, the method includes: Step S201: Obtain the energy value of the reference light and the energy value of the scattered light; Step S202: The particulate matter concentration is calculated based on the energy value of the reference light obtained during detection, the energy value of the scattered light obtained during detection, and the preset calibration data.

[0057] Although embodiments of the invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A dynamic surface scanning Raman imaging system, characterized in that, include: Beam output module, used to output collimated laser beam; A spatial light modulator is used to modulate the collimated laser beam into a dynamic structured light field corresponding to a preset excitation image; The excitation optical path module is used to image the dynamic structured light field onto the surface of the sample to be tested on the sample stage, forming an excitation light field distribution map corresponding to the preset excitation image; The sample stage is used to hold the sample to be tested; The optical path module is used to collect the Raman scattered light generated by the sample under test irradiated by the dynamic structured light field; An imaging spectrometer is used to receive the Raman scattered light and acquire Raman spectral data corresponding to the excitation light field distribution map based on the Raman scattered light. The control module is used to generate a corresponding driving signal according to a preset image sequence, the preset image sequence including multiple preset excitation images arranged in a set order, control the spatial light modulator to generate the corresponding dynamic structured light field through the driving signal, acquire Raman spectral data of multiple excitation light field distribution maps through the imaging spectrometer, and reconstruct and decouple the multiple Raman spectral data to obtain Raman imaging cube data.

2. The dynamic surface scanning Raman imaging system according to claim 1, characterized in that, The imaging spectrometer includes a slit, a grating, and a detector arranged sequentially along the incident direction of the light beam. The slit is used to image the Raman scattered light along the spatial dimension, the grating is used to disperse the Raman scattered light distributed along the spatial dimension and expand it along the spectral dimension, and the detector is used to acquire the Raman spectral data of the expanded Raman spectrum.

3. The dynamic surface scanning Raman imaging system according to claim 1, characterized in that, The beam output module includes a laser and a beam expander and collimator module. The laser is used to generate an initial laser beam, and the beam expander and collimator module is used to expand and collimate the initial laser beam to obtain a collimated laser beam with an aperture matching the spatial light modulator.

4. The dynamic surface scanning Raman imaging system according to claim 1, characterized in that, The excitation optical path module includes one or more lenses for imaging the dynamic structured light field onto the surface of the sample to be tested on the sample stage through a scanning device, thereby forming the excitation light field distribution map.

5. The dynamic surface scanning Raman imaging system according to claim 4, characterized in that, The scanning device is a galvanometer.

6. The dynamic surface scanning Raman imaging system according to claim 1, characterized in that, The optical path collection module includes a microscope objective and a filter. The microscope objective is used to collect the scattered light generated by the sample under test irradiated by the dynamic structured light field, and the filter is used to filter out Rayleigh scattered light from the scattered light to obtain Raman scattered light.

7. The dynamic surface scanning Raman imaging system according to claim 1, characterized in that, The preset excitation image is a multifocal array, line focusing, speckle field, or structured light field, and the excitation light field distribution map is a focal point array or a linear light spot.

8. A method for acquiring spectral data, characterized in that, Applied to the dynamic surface scanning Raman imaging system as described in any one of claims 1 to 7, comprising: A corresponding driving signal is generated based on a preset image sequence, wherein the preset image sequence includes multiple preset excitation images arranged in a set order; The driving signal controls the spatial light modulator to generate a corresponding dynamic structured light field, and the Raman spectral data of multiple excitation light field distribution maps are obtained by the imaging spectrometer. The Raman spectral data are reconstructed and decoupled to obtain Raman imaging cube data.

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