Line laser array type optical fiber multipoint Raman spectrum acquisition system

Abstract

The invention belongs to the technical field of Raman signal detection, and particularly discloses a line laser array type optical fiber multipoint Raman spectrum acquisition system which comprises a line laser conversion unit, a scattered light imaging unit, an optical fiber array unit and an imaging spectrometer which are sequentially arranged along a light path, wherein the line laser conversion unit is used for converting a received laser beam into line laser and outputting the line laser to an object to be measured to excite Raman scattering; the scattered light imaging unit is used for collecting Raman scattered light generated by an object to be measured, converting the Raman scattered light into a linear image and coupling the linear image into the input end of the optical fiber array unit; the output end of the optical fiber array unit is connected with the imaging spectrometer; and the imaging spectrometer is used for synchronously analyzing signal spectrums at different positions on the linear image. According to the invention, a line laser technology, an optical fiber array technology and a Raman spectrum acquisition technology are combined, multi-point synchronous excitation Raman scattering and multi-point batch acquisition and analysis are realized, and compared with existing Raman spectrum acquisition and detection equipment, the device is faster and more efficient.

Description

Technical Field

[0001] This application belongs to the technical field of Raman signal detection, and more specifically, relates to a line laser array type fiber optic multi-point Raman spectroscopy acquisition system. Background Art

[0002] Raman signal detection is an analytical technique based on the principle of Raman scattering. When a laser beam irradiates a sample, most photons are elastically scattered (Rayleigh scattering), while very few photons exchange energy with the sample molecules, resulting in a change in the frequency of the scattered light (Raman scattering). The Raman scattering spectra of different sample molecules are different. Therefore, Raman spectra can be used as the fingerprint of substances. For solutes in gases or liquids, their intensities can also reflect the concentration of the analyte. Based on the above principle, the Raman spectroscopy acquisition technique uses a laser to irradiate and excite the Raman scattering signals of each sampling point on the surface to be measured. After collection, a three-dimensional Raman spectroscopy data cube of the two-dimensional surface to be measured is obtained through a spectral analysis module, which is used to analyze and obtain information such as the substance components of the two-dimensional surface to be measured.

[0003] In order to obtain all the Raman scattering signals on the surface to be measured, traditional Raman spectroscopy acquisition systems usually combine single-point laser excitation with mechanical scanning technology. Each measurement obtains the Raman spectroscopy data of one sampling point, and finally all the data are stitched together and then analyzed to obtain all the spectral information of the two-dimensional surface to be measured. Since it is necessary to sequentially sample and detect each point on the surface to be measured, the speed is relatively slow. How to solve the problem of the slow detection speed of traditional Raman spectroscopy acquisition systems plays an important role in the development of Raman signal detection. Summary of the Invention

[0004] In view of the above defects or improvement requirements of the prior art, this application provides a line laser array type fiber optic multi-point Raman spectroscopy acquisition system, aiming to solve the technical problem of the slow signal detection of the existing Raman spectroscopy acquisition system.

[0005] To achieve the above object, in a first aspect, this application provides a line laser array type fiber optic multi-point Raman spectroscopy acquisition system, which includes a line laser conversion unit, a scattered light imaging unit, a fiber optic array unit, and an imaging spectrometer arranged in sequence along the optical path; The line laser conversion unit is used to convert the received laser beam into a line laser and output the line laser to the object to be measured to excite Raman scattering; The scattered light imaging unit is used to collect the Raman scattered light generated by the object to be measured, convert the Raman scattered light into a linear image and couple it into the input end of the fiber optic array unit; The output end of the fiber optic array unit is connected to the imaging spectrometer; The imaging spectrometer is used to batch-analyze the spectral information at different positions on the linear image.

[0006] Preferably, the line laser conversion unit includes a first collimating mirror and a cylindrical lens arranged in sequence along the optical path; the first collimating mirror is used to collimate the received laser beam, and the cylindrical lens is used to convert the collimated laser beam into a line laser.

[0007] Preferably, the line laser conversion unit further includes a narrowband filter, which is located on the optical path between the first collimating mirror and the cylindrical lens, and is used to filter out optical signals in non-light source bands from the collimated laser beam.

[0008] Preferably, the scattered light imaging unit includes a second collimating mirror, a dichroic mirror and a focusing mirror arranged in sequence along the optical path; the second collimating mirror is used to collimate the Raman scattered light generated by the object to be measured, the dichroic mirror is used to filter out the excitation light part in the Raman scattered light, and the focusing mirror is used to focus the Raman scattered light into a linear image and then couple it into the fiber array unit.

[0009] Preferably, the scattered light imaging unit further includes a broadband filter, which is located on the optical path between the second collimating mirror and the focusing mirror, and is used to filter out optical signals in non-system working bands from the Raman scattered light.

[0010] Preferably, the fiber array unit is composed of multiple optical fibers arranged linearly, and the optical signals at different positions on the linear image are coupled into the optical fibers at corresponding positions in the fiber array unit.

[0011] Preferably, the input end of the fiber array unit is parallel to the line laser, and the end face of the input end is located at the imaging plane of the linear image.

[0012] Preferably, the fiber array unit satisfies:

[0013] wherein, is the diameter of a single optical fiber in the fiber array unit; is the spacing between adjacent optical fibers in the fiber array unit; is the number of optical fibers in the fiber array unit; is the line width of the linear image.

[0014] Preferably, it further includes a sample stage, which is used to carry the object to be measured and move along a preset trajectory.

[0015] In a second aspect, the present application provides a collection method for a line laser array type fiber multi-point Raman spectroscopy collection system, including: Align the line laser conversion unit with the object to be measured; Align the scattered light imaging unit with the object to be measured, and set the scattered light imaging unit and the line laser conversion unit in the same plane and symmetric about the normal line of the surface of the object to be measured; The scattered light imaging unit collects the Raman scattered light generated by the object to be measured, converts the Raman scattered light into a linear image and couples it into the input end of the fiber optic array unit; The fiber optic array unit batch-synchronously transmits the optical signals at different positions on the linear image to the imaging spectrometer; The imaging spectrometer batch-collects and analyzes the optical signals at different positions on the linear image; The line laser array type fiber optic multi-point Raman spectroscopy acquisition system is any one of the line laser array type fiber optic multi-point Raman spectroscopy acquisition systems in the first aspect.

[0016] Generally speaking, compared with the prior art by the above technical solutions conceived in this application, the following beneficial effects are obtained: (1) The system of this application combines the line laser technology, the fiber optic array technology and the Raman spectroscopy acquisition technology, realizes multi-point synchronous excitation of Raman scattering and multi-point batch acquisition and analysis, and is faster and more efficient than the existing Raman spectroscopy acquisition and detection equipment.

[0017] (2) Compared with the traditional single-point laser excitation of Raman scattering, the system of this application uses a cylindrical lens to convert a point light source into a line laser, and simultaneously excites multiple points on the surface of the object to be measured to generate Raman scattering through the line laser, and its excitation efficiency is higher.

[0018] (3) This application images the Raman scattered light generated by the line laser exciting the surface of the object to be measured into a linear image, and then collects the signals of the linear image through a linear fiber optic array. The fibers at different positions in the linear fiber optic array collect the scattered signals at different positions, thereby realizing multi-point batch acquisition of Raman scattering signals, and its acquisition efficiency is higher.

[0019] (4) The system structure of this application is simple and easy to debug. Before use, only the input end of the linear fiber optic array needs to be aligned with the Raman scattering imaging to start the detection. Description of the Drawings

[0020] Figure 1 It is a schematic diagram of the composition structure of the line laser array type fiber optic multi-point Raman spectroscopy acquisition system provided by an embodiment of this application.

[0021] Figure 2 It is a schematic diagram of the structure of the excitation optical path arm in the focusing dimension provided by an embodiment of this application.

[0022] Figure 3 It is a schematic diagram of the structure of the excitation optical path arm in the non-focusing dimension provided by an embodiment of this application.

[0023] Figure 4It is a schematic structural diagram of the collection optical path arm provided by an embodiment of the present application.

[0024] Figure 5 It is a schematic structural diagram of the end face of the fiber optic array provided by an embodiment of the present application.

[0025] In all the drawings, the same reference numerals are used to represent the same elements or structures, where: 1 is a laser light source; 2 is a collection optical fiber; 3 is a line laser conversion unit; 4 is a sample stage; 5 is a scattered light imaging unit; 6 is a fiber optic array unit; 7 is an imaging spectrometer; 8 is a first collimating mirror; 9 is a narrowband filter; 10 is a cylindrical lens; 11 is a second collimating mirror; 12 is a dichroic mirror; 13 is a broadband filter; 14 is a focusing mirror. Detailed implementation manners

[0026] In order to make the objectives, technical solutions and advantages of the present application more clear and understandable, the present application will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0027] The terms "first" and "second" etc. in the specification and claims of this article are used to distinguish different objects, rather than to describe a specific order of the objects. For example, the first collimating mirror and the second collimating mirror etc. are used to distinguish different collimating mirrors, rather than to describe the specific order of the collimating mirrors.

[0028] In the embodiments of the present application, words such as "exemplary" or "for example" are used to represent examples, illustrations or explanations. Any embodiment or design solution described as "exemplary" or "for example" in the embodiments of the present application should not be construed as being more preferred or having more advantages than other embodiments or design solutions. Exactly speaking, using words such as "exemplary" or "for example" aims to present relevant concepts in a specific way.

[0029] In the description of the embodiments of the present application, unless otherwise specified, the meaning of "multiple" refers to two or more. For example, multiple optical fibers refer to two or more optical fibers etc.

[0030] The embodiments of the present application will be described below with reference to the accompanying drawings in the embodiments of the present application.

[0031] The embodiments of the present application provide a line laser array type fiber optic multi-point Raman spectroscopy collection system, as Figure 1 shown in the schematic diagram of its structural composition: Specifically, it includes a laser light source 1, a collection optical fiber 2, a line laser conversion unit 3, a sample stage 4, a scattered light imaging unit 5, a fiber optic array unit 6 and an imaging spectrometer 7 arranged in sequence along the optical path.

[0032] The laser beam emitted by the laser light source 1 is transmitted and coupled into the line laser conversion unit 3 along the acquisition optical fiber 2. The selected acquisition optical fiber 2 in this embodiment is a multimode quartz optical fiber, and the core diameter, cladding diameter, and coating diameter of the optical fiber are 200 , 400 , and 800 , respectively.

[0033] In this embodiment, the laser conversion unit 3 converts the received laser beam into a line laser.

[0034] As Figure 2 shown, the laser conversion unit 3 is composed of a first collimating mirror 8, a narrowband filter 9, and a cylindrical lens 10 arranged in sequence along the optical path. The first collimating mirror 8 first collimates the laser beam received by the laser conversion unit 3. The narrowband filter 9 then performs narrowband filtering on the collimated laser beam to filter out stray light outside the operating frequency band of the laser light source. After that, the cylindrical lens 10 converts the collimated laser beam into a line laser.

[0035] The laser conversion unit 3 converts the laser beam into a line laser by utilizing the functional properties of the cylindrical lens. One surface of the cylindrical lens has curvature, and the other surface is flat.

[0036] As Figure 2 shown, the cylindrical lens 10 has a focusing ability similar to that of a spherical lens in the curvature direction (meridional direction), and the collimated light beam will be focused to a point. As Figure 3 shown, in the flat direction (sagittal direction) of the cylindrical lens 10, the light rays are hardly deflected and remain collimated or divergent. Thus, after passing through the cylindrical lens 10, the collimated laser beam is focused into a line in the curvature direction and remains parallel in the flat direction, finally forming a uniform linear laser.

[0037] After the laser beam is converted into a line laser, it is directed at the object to be measured on the sample stage 4, and Raman scattered light is excited and generated in the linear area where the object to be measured is irradiated. Compared with the traditional point laser excitation of Raman scattering, in this application, the cylindrical lens is used to convert the laser beam into a line laser, and the object to be measured is irradiated with the line laser, and Raman scattered light is excited and generated at multiple points in the linear area on its surface, and its excitation efficiency is higher.

[0038] The scattered light imaging unit 5 is used to collect the Raman scattered light generated by the object to be measured. In order to ensure that the scattered light imaging unit 5 can collect the Raman scattered light, the position and orientation of the scattered light imaging unit 5 need to be adjusted: First, align the scattered light imaging unit 5 with the object to be measured; Then, set the scattered light imaging unit 5 and the line laser conversion unit 3 to be in the same plane and symmetric about the normal line of the surface of the object to be measured. Thus, the scattered light imaging unit 5 can collect the Raman scattered light.

[0039] The scattered light imaging unit 5 collects the Raman scattered light generated by the object to be measured, converts the Raman scattered light into a linear image and couples it into the input end of the fiber optic array unit 6; As Figure 4 shown, the scattered light imaging unit 5 includes a second collimating mirror 11, a dichroic mirror 12, a broadband filter 13 and a focusing mirror 14 arranged in sequence along the optical path.

[0040] The second collimating mirror 11 collimates the Raman scattered light generated by the object to be measured. The collimated Raman scattered light then passes through the dichroic mirror 12, and the excitation light component in the Raman scattered light is filtered out. The broadband filter 13 filters out the optical signals in the non-system operating band from the Raman scattered light. Finally, the collimated and filtered Raman scattered light is focused by the focusing mirror 14 to form a linear image.

[0041] The focal length ratio of the second collimating mirror 11 and the focusing mirror 14 determines the magnification of the linear image. In this embodiment, the magnification of the linear image is 1.

[0042] The larger the magnification, the larger the numerical aperture in the image space. The numerical aperture in the image space needs to match the numerical aperture of the optical fibers in the fiber optic array unit 6. Therefore, in actual use, the magnification of the linear image will be modulated according to requirements.

[0043] The linear image is then coupled into the fiber optic array unit 6. As Figure 5 shown, in this embodiment, the fiber optic array unit 6 is composed of 16 multimode optical fibers arranged linearly, with a core diameter of 105 , and a cladding diameter of 125 . In this embodiment, the selection of the core diameter and the cladding diameter determines the numerical aperture of the optical fiber.

[0044] The optical signals at different positions on the linear image are coupled into the optical fibers at the corresponding positions in the fiber optic array unit.

[0045] To ensure that the fiber optic array unit 6 can collect all the optical signals of the linear image, in this embodiment, the input end of the fiber optic array unit 6 and the line laser must be parallel to each other, and the fiber optic array unit satisfies:

[0046] Among them, is the diameter of a single optical fiber in the fiber optic array unit; is the spacing between adjacent optical fibers in the fiber optic array unit; is the number of optical fibers in the fiber optic array unit; is the line width of the linear image.

[0047] In this application, the imaging of Raman scattering generated by line laser excitation on the surface of the object to be measured is a linear image, and then the linear fiber array is used to collect signals from the linear image. The fibers at different positions in the linear fiber array collect scattered signals at different positions, thereby realizing multi-point batch collection of Raman scattering signals, and the collection efficiency is higher.

[0048] The output end of the fiber array unit 6 is connected to the imaging spectrometer, and the optical signals at each position point of the linear image are transmitted to the imaging spectrometer 7. Subsequently, the spectrometer 7 synchronously and batch-analyzes the optical signals at each position point to obtain the spectral information at each position point.

[0049] The imaging spectrometer is a high-end optical instrument that combines spatial imaging and spectral analysis, and can simultaneously obtain the two-dimensional spatial information and continuous spectral information of the target object to form a "data cube". In the embodiment of this application, the imaging spectrometer 7 analyzes the optical signals at each position point on the linear image, and obtains the spectral information (spatial x, spatial y, wavelength λ) of each point in the linear part of the object to be measured irradiated by the line laser. Its spatial resolution is related to the number of fibers in the fiber array unit 6. The larger the number of fibers, the higher the spatial resolution, and vice versa.

[0050] In this embodiment, the sample stage 4 is provided with a control motor, and a preset motion trajectory is set in the control motor. The sample stage 4 is driven to move horizontally by the control motor, thereby realizing the scanning acquisition and analysis of the surface of the sample to be measured on the sample stage 4.

[0051] The system structure of this application is simple and easy to debug. Before use, only the input end of the linear fiber array needs to be aligned with the Raman scattering imaging to start detection.

[0052] It should be understood that expressions such as "including" and "may include" that can be used in this application indicate the existence of the disclosed functions, operations, or constituent elements, and do not limit one or more additional functions, operations, and constituent elements. In this application, terms such as "including" and / or "having" can be interpreted as indicating a specific characteristic, number, operation, constituent element, component, or a combination thereof, but cannot be interpreted as excluding the existence or possibility of addition of one or more other characteristics, numbers, operations, constituent elements, components, or a combination thereof.

[0053] In addition, in this application, the expression "and / or" includes any and all combinations of the associated listed words. For example, the expression "A and / or B" may include A, may include B, or may include both A and B.

[0054] In the description of the embodiments of the present application, it should be noted that unless otherwise clearly specified and limited, the term "connection" should be understood in a broad sense. For example, "connection" can be a detachable connection or a non-detachable connection; it can be a direct connection or an indirect connection through an intermediate medium. Among them, "fixed connection" means that the two are connected and the relative positional relationship after connection remains unchanged. "Rotational connection" means that the two are connected and can rotate relative to each other after connection. "Sliding connection" means that the two are connected and can slide relative to each other after connection. The orientation terms mentioned in the embodiments of the present application, such as "top", "bottom", "inner", "outer", "left", "right", etc., are only references to the directions in the drawings. Therefore, the orientation terms used are for better and clearer explanation and understanding of the embodiments of the present application, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus cannot be understood as a limitation on the embodiments of the present application.

[0055] In addition, in the embodiments of the present application, mathematical concepts such as symmetry, equality, parallelism, and perpendicularity are mentioned. These limitations are all in view of the current technological level, rather than absolute strict definitions in the mathematical sense. A small deviation is allowed, and approximate symmetry, approximate equality, approximate parallelism, approximate perpendicularity, etc. are all acceptable. For example, when it is said that A is parallel to B, it means that A is parallel to B or approximately parallel to B, and the included angle between A and B can be between 0 degrees and 10 degrees. When it is said that A is perpendicular to B, it means that A is perpendicular to B or approximately perpendicular to B, and the included angle between A and B can be between 80 degrees and 100 degrees.

[0056] The above is only the specific implementation manner of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present application can easily think of changes or substitutions, which should all be covered by the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A line laser array optical fiber multi-point Raman spectrum acquisition system, characterized in that: The line laser array optical fiber multi-point Raman spectrum acquisition system comprises a line laser conversion unit (3), a scattered light imaging unit (5), an optical fiber array unit (6) and an imaging spectrometer (7) which are sequentially arranged along the optical path; The line laser conversion unit (3) is used to convert the received laser beam into a line laser, and output the line laser to the object to be measured to stimulate Raman scattering; The scattered light imaging unit (5) is used to collect Raman scattered light generated by the object to be measured, convert the Raman scattered light into a linear image, and couple it into the input end of the optical fiber array unit (6); The output end of the optical fiber array unit (6) is connected to an imaging spectrometer (7); The imaging spectrometer (7) is used to batch analyze spectral information at different positions on the linear image.

2. The linear laser array optical fiber multi-point Raman spectrum acquisition system according to claim 1, characterized in that: The line laser conversion unit (3) comprises a first collimator (8) and a cylindrical lens (10) which are arranged in sequence along the optical path; the first collimator (8) is used to collimate the received laser beam, and the cylindrical lens (10) is used to convert the collimated laser beam into a line laser.

3. The linear laser array optical fiber multi-point Raman spectrum acquisition system according to claim 2, characterized in that: The line laser conversion unit (3) further comprises a narrowband filter (9), wherein the narrowband filter (9) is located on the optical path between the first collimator (8) and the cylindrical lens (10), and the narrowband filter (9) is used to filter out optical signals in a non-light source band from the collimated laser beam.

4. The linear laser array optical fiber multi-point Raman spectrum acquisition system according to claim 1, characterized in that: The scattered light imaging unit (5) comprises a second collimator (11), a dichroic mirror (12) and a focusing mirror (14) which are arranged in sequence along the light path; the second collimator (11) is used to collimate the Raman scattered light generated by the object to be measured, the dichroic mirror (12) is used to filter out the excitation light portion of the Raman scattered light, and the focusing mirror (14) is used to focus the Raman scattered light into a linear image and then couple it into the optical fiber array unit (6).

5. The linear laser array optical fiber multi-point Raman spectrum acquisition system according to claim 1, characterized in that: The scattered light imaging unit (5) further comprises a broadband filter (13), which is located on the optical path between the second collimating mirror (11) and the focusing mirror (14) and is used to filter out optical signals outside the system operating band from the Raman scattered light.

6. The linear laser array optical fiber multi-point Raman spectrum acquisition system according to claim 1, characterized in that: The optical fiber array unit (6) is composed of a plurality of optical fibers arranged linearly, and optical signals at different positions on the linear image are coupled into optical fibers at corresponding positions in the optical fiber array unit (6).

7. The linear laser array optical fiber multi-point Raman spectrum acquisition system according to claim 6, characterized in that: The input end of the optical fiber array unit (6) is parallel to the line laser, and the end face of the input end is located at the imaging plane of the linear image.

8. The linear laser array optical fiber multi-point Raman spectrum acquisition system according to claim 6, characterized in that: The optical fiber array unit (6) satisfies: in, is the diameter of a single optical fiber in the optical fiber array unit; is the spacing between adjacent optical fibers in the optical fiber array unit; is the number of optical fibers in the optical fiber array unit; Line width of the line image.

9. The linear laser array optical fiber multi-point Raman spectrum acquisition system according to claim 1, characterized in that: It also comprises a sample stage (4), wherein the sample stage (4) is used to carry the object to be tested and move along a preset trajectory.

10. A method for collecting Raman spectra of a linear laser array optical fiber multi-point Raman spectrum collection system, characterized in that: include: Aim the line laser conversion unit (3) at the object to be measured; Aligning the scattered light imaging unit (5) with the object to be measured, and arranging the scattered light imaging unit (5) and the line laser conversion unit (3) to be located in the same plane and symmetrical about the normal line of the surface of the object to be measured; The scattered light imaging unit (5) collects the Raman scattered light generated by the object to be measured, converts the Raman scattered light into a linear image, and couples the linear image into the input end of the optical fiber array unit (6); The optical fiber array unit (6) synchronously transmits optical signals at different positions on the linear image to the imaging spectrometer (7) in batches; The imaging spectrometer (7) collects and analyzes the optical signals at different positions on the linear image in batches; The linear laser array type optical fiber multi-point Raman spectrum acquisition system is the linear laser array type optical fiber multi-point Raman spectrum acquisition system as claimed in any one of claims 1 to 9.

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