High-sensitivity confocal raman spectroscopy fast measurement method and device based on dual two-dimensional MEMS micromirror scanning

Abstract

The application relates to a high-sensitivity confocal Raman spectrum fast measurement method and device based on two-dimensional MEMS micromirror scanning, and belongs to the technical field of microscopic spectrum imaging. The method utilizes two pieces of two-dimensional MEMS micromirrors to realize light beam transverse scanning, omits scanning lenses and tube lenses, utilizes a dichroic light splitting system to realize lossless separation of reflected light and Raman scattering light, utilizes the reflected light to construct a confocal microscopic imaging system, realizes fast high-spatial-resolution detection of the geometric appearance of a sample, utilizes the Raman scattering light to construct a confocal Raman spectrum detection system, for a sample with a relatively smooth surface, single-layer scanning can be carried out to quickly complete Raman spectrum detection of the surface of the sample, and for a sample with a relatively large surface fluctuation, point-by-point focusing can be carried out to realize high-spatial-resolution Raman spectrum detection. The application has the advantages of high sensitivity, fast measurement speed, wide sample adaptability (a sample with a relatively large surface fluctuation can be measured), high integration degree and simple structure.

Description

Technical Field

[0001] This invention pertains to microscopic spectral imaging, specifically to a method and apparatus for rapid measurement of highly sensitive confocal Raman spectroscopy using dual two-dimensional MEMS micromirror scanning. Background Technology

[0002] Laser confocal Raman spectroscopy combines microscopic analysis with Raman spectroscopy. Utilizing the unique axial response characteristics of confocal lasers, it focuses a laser beam onto the sample surface, allowing the acquisition of parameters such as molecular composition, concentration, temperature, and stress changes in micro-regions of the sample; hence, it is known as a molecular probe. Furthermore, this technique can detect Raman signals at different depths of the sample, enabling tomographic scanning and high spatial resolution spectroscopic detection without destructive testing. Due to its unique advantages, laser confocal Raman spectroscopy has become an extremely important tool for analyzing material composition and has been widely applied in fields such as physical chemistry, materials science, biomedicine, geological exploration, forensic investigation, and industrial automated detection.

[0003] The principle of traditional confocal Raman spectroscopy detection system is as follows: Figure 1 As shown, the laser emitted from the laser source is reflected by the dichroic spectral system and focused onto the sample surface by the objective lens, exciting Raman scattered light carrying the sample's spectral information. The Raman scattered light is collected by the measuring objective lens, filtered by the dichroic spectral system to remove reflected light and Rayleigh light, and then focused by the converging lens to the Raman confocal pinhole. The Raman scattered spectrum carrying the sample's spectral information is then measured by the spectral detection system. The sample is moved by the three-dimensional mechanical scanning system to realize the Raman spectral detection of different regions of the sample.

[0004] Traditional confocal Raman spectroscopy detection systems suffer from the following drawbacks: 1. To reduce energy loss from Raman scattering and ensure spectral detection sensitivity, a relatively large pinhole is typically used for focal point localization. The large pinhole size directly affects the full width at half maximum (FWHM) of the confocal axial response curve, reducing the system's spatial resolution. 2. Traditional confocal Raman spectroscopy systems can only perform spectral detection and cannot acquire sample morphology information. 3. The use of a mechanical translation stage results in slow scanning speeds and long scan times. 4. The large size and weight of the mechanical translation stage hinder integrated and portable design. These factors limit the application of confocal Raman spectroscopy detection technology in certain fields and restrict its further development.

[0005] To improve the scanning speed of Raman spectroscopy, galvanometer-based beam scanning modes are widely used. However, galvanometer systems require delaying the optical path to adjust the conjugate relationship between the mirror and the objective lens's back pupil. The delay optical path requires a large space volume, which is not convenient for integration. Moreover, the introduction of lenses increases spectral chromatic aberration and reduces the detection efficiency of the spectrum.

[0006] In summary, the existing confocal Raman spectrum detection method has many limitations, and how to realize high-sensitivity Raman scattering spectrum detection by a fast and simple method is a difficulty in current research. SUMMARY

[0007] The purpose of the present application is to overcome the deficiencies of the prior art, and a high-sensitivity confocal Raman spectrum fast measurement method based on double two-dimensional MEMS micromirror scanning is proposed, which can realize the fast detection of the micro-area Raman spectrum of the sample surface, compared with the scanning system based on the galvanometer, the system eliminates the scanning lens and the tube lens, reduces the optical elements and the optical path, and improves the sensitivity of the Raman spectrum detection. Moreover, the present application uses the abandoned reflected light in the confocal Raman spectrum detection to construct a confocal microscopic imaging system, realizes the high-resolution imaging of the three-dimensional geometric profile of the sample, and further realizes the high spatial resolution imaging and detection of the confocal Raman spectrum with the atlas.

[0008] The purpose of the present application is realized by the following technical solutions.

[0009] The present application discloses a high-sensitivity confocal Raman spectrum fast measurement method based on double two-dimensional MEMS micromirror scanning, which specifically comprises the following processes:

[0010] Step one, the excitation light beam emitted by the light source system passes through the beam splitter and the dichroic beam splitting system, and is then reflected by the double two-dimensional MEMS micromirror scanning system, and is focused on the measured sample by the measurement objective lens, and excites the Raman scattering light and the reflected light carrying the micro-area characteristics of the sample;

[0011] Step two, the Raman scattering light and the reflected light are collected by the measurement objective lens, and after returning along the original path of the double two-dimensional MEMS micromirror scanning system, they are divided into two beams by the dichroic beam splitting system, one of which is reflected to the confocal detection system by the dichroic beam splitting system, and the other of which passes through the dichroic beam splitting system and enters the confocal Raman spectrum detection system;

[0012] Step three, the reflected light reaching the confocal detection system is focused by the third converging lens, enters the confocal pinhole at the focus position of the third converging lens, and is then received by the photodetector;

[0013] When the axial scanning system drives the measurement objective lens to perform axial scanning, the photodetector obtains an axial light intensity response curve varying with the axial position, and the axial focusing of the initial scanning point of the sample can be realized through the axial light intensity response curve;

[0014] Step four, the Raman scattering light entering the confocal Raman spectrum detection system is focused by the first converging lens, enters the Raman spectrum collection pinhole, and is then received by the second converging lens after being focused by the second converging lens, thereby realizing the high-sensitivity detection of the Raman spectrum of the sample;

[0015] Step five, the double two-dimensional MEMS micro-mirror scanning system controls the first MEMS micro-mirror and the second MEMS micro-mirror to perform yaw, controls the measurement light beam to perform "S type" scanning on the surface of the measured sample, so as to realize the lateral rapid scanning of the surface of the measured sample, and thus the rapid and high-sensitivity detection of the Raman spectrum of the sample surface is completed.

[0016] As a preferred scheme: the lateral rapid scanning of the light beam is realized by the yaw of the first MEMS micro-mirror and the second MEMS micro-mirror, and the relationship between the yaw angle of the two-dimensional MEMS micro-mirror and the scanning angle of the light beam is described in detail.

[0017] As a preferred scheme: for the sample with relatively large surface undulation, the point-by-point focusing scanning mode can be used to obtain the high spatial resolution Raman spectrum image of the sample, and the specific steps are as follows:

[0018] In the step three, the reflected light reaching the confocal detection system is focused by the third converging lens, enters the confocal pinhole at the focus position of the third converging lens, and is then received by the photodetector; when the axial scanning system drives the measurement objective lens to perform axial scanning, the photodetector obtains an axial light intensity response curve varying with the axial position, and the position detection and high-precision focusing of the sample can be realized through the axial light intensity response curve.

[0019] In the step four, after focusing is completed, the focus point of the measurement objective lens is moved to the measured position of the sample to excite Raman scattering light, the Raman scattering light passes through the dichroic beam splitting system, is focused by the first converging lens, enters the Raman spectrum collection pinhole, is then focused by the second converging lens, and is received by the spectrum detector, so that high spatial resolution Raman spectrum detection is realized.

[0020] In the step five, the double two-dimensional MEMS micro-mirror scanning system controls the first MEMS micro-mirror and the second MEMS micro-mirror to perform yaw, controls the measurement light beam to move to the next scanning point of the measured sample, and repeats the above steps until the scanning of all the set points on the surface of the sample is completed.

[0021] As a preferred scheme: the high-precision geometric morphology obtained through the confocal detection light path and the high spatial resolution Raman spectrum information obtained through the confocal Raman detection light path can realize the "graph integration" imaging of the sample with high spatial resolution.

[0022] The application further discloses a high-sensitivity confocal Raman spectrum rapid measurement device based on double two-dimensional MEMS micro-mirror scanning, which comprises a light source system for generating an excitation light beam, a beam splitter, a dichroic beam splitting system, a double two-dimensional MEMS micro-mirror scanning system, a measurement objective lens, an axial scanning system, a measured sample, a confocal Raman spectrum detection system, a confocal detection system and a computer control and display system.

[0023] The light source system comprises a laser, a converging objective lens, a spatial light filtering pinhole and a collimating lens for generating an excitation light beam;

[0024] The dual two-dimensional MEMS micro-mirror scanning system comprises a first MEMS micro-mirror and a second MEMS micro-mirror for performing two-dimensional lateral scanning of the light beam;

[0025] The axial scanning system is connected with the measurement objective lens for driving the objective lens to perform axial displacement;

[0026] The Raman spectrum detection system comprises a first converging lens, a Raman spectrum collection pinhole, a second converging lens and a spectrum detector for performing Raman spectrum detection;

[0027] The confocal detection system comprises a third converging lens, a confocal pinhole and a photoelectric detector for performing microscopic topography measurement and high-precision axial focusing;

[0028] The computer control and display system is connected with the light source system, the dual two-dimensional MEMS micro-mirror scanning system, the axial scanning system, the confocal Raman spectrum detection system and the confocal detection system, and is a control center of the whole measuring device for adjusting the output power of the excitation light beam, controlling the scanning frequency, scanning angle and scanning range of the MEMS micro-mirror, the scanning speed, scanning step and scanning range of the axial scanning system and processing and displaying the collected reflected light and Raman spectrum.

[0029] Advantages

[0030] The method has the following advantages:

[0031] 1. The two-dimensional MEMS micro-mirror is used for light beam scanning, and the one-to-one correspondence between the MEMS micro-mirror deflection angle and the light beam scanning angle is used to realize rapid and high-precision scanning of the sample micro-area;

[0032] 2. The second MEMS micro-mirror is used to adjust the light beam to ensure that the light spot at the objective lens back pupil is stationary, and the scanning lens and the tube lens are omitted, the system space volume is greatly reduced, the structure is simple, and the integration degree of the system is improved;

[0033] 3. The scanning lens and the tube lens are omitted, the diameter of the collected light beam is not compressed, no chromatic aberration is introduced to the spectrum detection system, the light spot quality at the pinhole of the spectrum collection system is improved, more spectrum signals are not blocked by the pinhole, the use of optical components and the system optical path are reduced, and the spectrum detection efficiency is greatly improved;

[0034] 4. The application provides a high-precision two-dimensional MEMS micro-mirror scanning control method, which utilizes the one-to-one correspondence between the MEMS micro-mirror deflection angle and the light beam scanning angle to deduce the control equation of the MEMS micro-mirror, adopts the inverse tangent control mode to eliminate scanning distortion, and adopts a triangular wave at the control waveform turning point to rotate, so as to realize high-precision scanning of a sample micro area.

[0035] 5. The application combines high axial resolution laser confocal microscopy technology and Raman spectrum detection technology, and can utilize the characteristic that the maximum point of the high axial resolution laser confocal axial response curve is accurately corresponding to the focus of a measuring objective, realize accurate focusing of a measured sample, simultaneously acquire the geometric position and Raman spectrum signal of the sample, and greatly improve the micro area spectrum detection capability of an existing confocal Raman spectrum detection system.

[0036] 6. The method has the advantages of wide sample adaptability, and can quickly measure a sample with a single layer and a sample with large surface undulation by point-by-point focusing. BRIEF DESCRIPTION OF DRAWINGS

[0037] The application will be further described below in combination with the drawings and embodiments:

[0038] Figure 1 is a schematic diagram of a traditional confocal Raman spectrum imaging method;

[0039] Figure 2 is a schematic diagram of a high-sensitivity confocal Raman spectrum fast measurement method of the two-dimensional MEMS micro-mirror scanning of the application;

[0040] Figure 3 is a schematic diagram of a high-sensitivity confocal Raman spectrum fast measurement device of the two-dimensional MEMS micro-mirror scanning of the application;

[0041] Figure 4 is a control voltage waveform diagram of two two-dimensional MEMS micro-mirrors in the embodiments of the application.

[0042] In the figure: 1-light source system, 2-dichroic mirror, 3-two-way dichroic splitting system, 4-two-dimensional MEMS micro-mirror scanning system, 5-first MEMS micro-mirror, 6-second MEMS micro-mirror, 7-measuring objective, 8-axial scanning system, 9-measured sample, 10-object table, 11-confocal Raman spectrum detection system, 12-first converging lens, 13-Raman spectrum collection pinhole, 14-second converging lens, 15-spectrum detector, 16-confocal detection system, 17-third converging lens, 18-confocal pinhole, 19-photodetector, 20-confocal axial light intensity response curve, 21-'S' scanning, 22-laser, 23-converging objective, 24-space light filtering pinhole, 25-collimating lens, 26-computer control and display system. DETAILED DESCRIPTION

[0043] To better illustrate the purposes and advantages of the present application, the summary will be further described below in conjunction with the drawings and examples.

[0044] See Figure 3 The embodiment of the present application is a high-sensitivity confocal Raman spectrum fast measuring device for two-dimensional MEMS micromirror scanning, which comprises a light source system for generating an excitation light beam, a beam splitter, a dichroic beam splitting system, a two-dimensional MEMS micromirror scanning system, a measuring objective lens, an axial scanning system, a measured sample, a confocal Raman spectrum detection system, a confocal detection system, and a computer control and display system.

[0045] The light source system comprises a laser, a converging objective lens, a spatial light filtering pinhole, and a collimating lens, which are used to generate the excitation light beam.

[0046] The two-dimensional MEMS micromirror scanning system comprises a first MEMS micromirror and a second MEMS micromirror, which are used to perform two-dimensional lateral scanning of the light beam.

[0047] The axial scanning system is connected with the measuring objective lens, and is used to drive the objective lens to perform axial displacement.

[0048] The Raman spectrum detection system comprises a first converging lens, a Raman spectrum collection pinhole, a second converging lens, and a spectrum detector, which are used to perform Raman spectrum detection.

[0049] The confocal detection system comprises a third converging lens, a confocal pinhole, and a photoelectric detector, which are used to perform microscopic topography measurement and high-precision axial focusing.

[0050] The computer control and display system is connected with the light source system, the two-dimensional MEMS micromirror scanning system, the axial scanning system, the confocal Raman spectrum detection system, and the confocal detection system, and is the control center of the entire measuring device, which is used to adjust the output power of the excitation light beam, control the scanning frequency, scanning angle, and scanning range of the MEMS micromirror, the scanning speed, scanning step, and scanning range of the axial scanning system, and process and display the collected reflected light and Raman spectrum.

[0051] The measuring method of the embodiment specifically comprises the following processes:

[0052] Step one, the excitation light beam emitted by the light source system passes through the beam splitter and the dichroic beam splitting system, and is then reflected by the two-dimensional MEMS micromirror scanning system, and is converged by the measuring objective lens to the measured sample, exciting Raman scattered light and reflected light carrying the micro-region characteristics of the sample.

[0053] Step two, the Raman scattered light and the reflected light are collected by the measuring objective lens, and after returning along the original path of the double two-dimensional MEMS micromirror scanning system, they are divided into two beams by the dichroic beam splitting system, one of which is reflected to the confocal detection system through the dichroic beam splitting system, and the other is transmitted to the confocal Raman spectrum detection system through the dichroic beam splitting system;

[0054] Step three, the reflected light reaching the confocal detection system is focused by the third converging lens, enters the confocal pinhole at the focal point position of the third converging lens, and is then received by the photodetector;

[0055] When the axial scanning system drives the measuring objective lens to perform axial scanning, the photodetector obtains an axial light intensity response curve varying with the axial position, and the axial focusing of the initial scanning point of the sample can be realized through the axial light intensity response curve;

[0056] Step four, the Raman scattered light entering the confocal Raman spectrum detection system is focused by the first converging lens, enters the Raman spectrum collection pinhole, and is then received by the spectrum detector after being converged by the second converging lens, realizing high-sensitivity detection of the Raman spectrum of the sample;

[0057] Step five, the double two-dimensional MEMS micromirror scanning system controls the first MEMS micromirror and the second MEMS micromirror to perform deflection, controls the measurement light beam to perform "S-type" scanning on the surface of the measured sample, so as to realize the lateral rapid scanning of the surface of the measured sample, and thus complete the rapid and high-sensitivity detection of the Raman spectrum of the sample surface.

[0058] For a sample with relatively large surface undulation, a point-by-point focusing scanning method can be used to obtain a high spatial resolution Raman spectrum image of the sample, and the specific steps are as follows:

[0059] Step one, the excitation light beam emitted by the light source system passes through the beam splitter and the dichroic beam splitting system, and is then reflected by the double two-dimensional MEMS micromirror scanning system, and is converged by the measuring objective lens to the measured sample, exciting the Raman scattered light and the reflected light carrying the micro-region characteristics of the sample;

[0060] Step two, the Raman scattered light and the reflected light are collected by the measuring objective lens, and after returning along the original path of the double two-dimensional MEMS micromirror scanning system, they are divided into two beams by the dichroic beam splitting system, one of which is reflected to the confocal detection system through the dichroic beam splitting system, and the other is transmitted to the confocal Raman spectrum detection system through the dichroic beam splitting system;

[0061] Step three, the reflected light reaching the confocal detection system is focused by the third converging lens, enters the confocal pinhole at the focal point position of the third converging lens, and is then received by the photodetector; when the axial scanning system drives the measuring objective lens to perform axial scanning, the photodetector obtains an axial light intensity response curve varying with the axial position, and the position detection and high-precision focusing of the sample can be realized through the axial light intensity response curve;

[0062] Step four, after focusing, the measuring objective focus is moved to the sample measured position to excite Raman scattering light, after passing through the dichroic beam splitting system, the Raman scattering light is focused by the first converging lens, enters the Raman spectrum collection pinhole, and is then focused by the second converging lens and received by the spectrum detector, realizing high spatial resolution Raman spectrum detection;

[0063] Step five, the first MEMS micro-mirror and the second MEMS micro-mirror are controlled to perform deflection by the double two-dimensional MEMS micro-mirror scanning system, the measuring beam focus is moved to the next scanning point of the measured sample, and the above steps are repeated until the scanning of all points on the surface of the sample is completed.

[0064] The basic idea of the application is to realize two-dimensional lateral scanning of the light beam by using the deflection of two two-dimensional MEMS micro-mirrors, to realize fast and high-sensitivity spectrum detection and microscopic imaging of the measured sample, and to realize Figure 2 It is a schematic diagram of a high-sensitivity confocal Raman spectrum fast measurement method of double two-dimensional MEMS micro-mirror scanning of the application, and the measurement steps are as follows:

[0065] The excitation light beam emitted by the light source system 1 passes through the beam splitter 2 and the dichroic beam splitting system 3, is then reflected by the double two-dimensional MEMS micro-mirror scanning system 4, is converged by the measuring objective 7 to the measured sample 9, and excites Raman scattering light and reflected light carrying the micro-region characteristic parameter information of the sample. After being collected by the measuring objective 7, the Raman scattering light and the reflected light are divided into two beams by the dichroic beam splitting system 3, the reflected light reflected by the dichroic beam splitting system 3 enters the confocal detection system 16 for position detection, and the Raman scattering light transmitted by the dichroic beam splitting system 3 enters the confocal Raman spectrum detection system 11 for Raman spectrum detection.

[0066] The reflected light reaching the confocal detection system 16 is focused by the third converging lens 17, enters the confocal pinhole 18 at the focal point of the third converging lens 17, and is then received by the photodetector 19. When the axial scanning system 8 drives the measuring objective 7 to perform axial scanning, the photodetector 19 obtains an axial light intensity response curve 20 varying with the axial position, and through the axial light intensity response curve 20, the position detection and high-precision focusing of the sample can be realized, and the Raman scattering light at the focal point position can be collected.

[0067] The Raman scattering light reaching the confocal Raman spectrum detection system 11 is focused by the first converging lens 12, enters the Raman spectrum collection pinhole 13, is then focused by the second converging lens 14, and is received by the spectrum detector 15, realizing sample Raman spectrum detection.

[0068] The deflection of the light beam is controlled by the double two-dimensional MEMS micro-mirror scanning system 4, and the "S-type" scanning 21 of the surface of the sample is completed, so that the position information and the Raman spectrum information of each point on the surface of the sample are quickly obtained.

[0069] In particular, for the sample with large surface relief, the point-by-point focusing scanning mode can be used to obtain the high spatial resolution Raman spectrum information of the sample surface.

[0070] In particular, the high-precision geometric profile information obtained by the confocal detection light path and the high spatial resolution Raman spectrum information obtained by the confocal Raman light path are fused, and then high spatial resolution "graph and spectrum integration" imaging is realized.

[0071] The first MEMS micromirror and the second MEMS micromirror both adopt two-dimensional MEMS scanning mirrors, the dichroic beam splitting system 3 adopts a Notch Filter, the spectral detector 15 adopts a Raman spectrometer, and the laser 22 adopts a 532nm semiconductor continuous laser.

[0072] The first MEMS micromirror and the second MEMS micromirror both adopt two-dimensional MEMS scanning mirrors, the dichroic beam splitting system 3 adopts a Notch Filter, the spectral detector 15 adopts a Raman spectrometer, and the laser 22 adopts a 532nm semiconductor continuous laser. Figure 3 It is a schematic diagram of a high-sensitivity confocal Raman spectrum fast measurement device of a double two-dimensional MEMS micromirror scanning according to an embodiment of the present application, and the specific detection process is as shown below:

[0073] Firstly, the light source system is composed of a laser 22, a converging objective lens 23, a spatial light filtering pinhole 24 and a collimating lens 25. The laser emitted by the laser 22 is converged by the converging objective lens 23, enters the spatial light filtering pinhole 24, and then is collimated and expanded by the collimating lens 25 to generate a parallel excitation light beam. The excitation light beam is reflected by the Notch Filter 3 after passing through the beam splitter 2, and then enters the measurement objective lens 7 after being reflected by the first MEMS micromirror and the second MEMS micromirror. Finally, the excitation light beam is converged on the measured sample 9 by the measurement objective lens, and excites the Raman scattered light and the reflected light carrying the micro-region characteristic parameters of the measured sample 9.

[0074] Then, the double two-dimensional MEMS micromirror scanning system 4 controls the deflection angles of the first MEMS micromirror 5 and the second MEMS micromirror 6, so as to realize the "S-type" scanning 21 of the measurement light beam on the surface of the measured sample 9. The functional relationship between the deflection angle of the MEMS micromirror and the scanning angle of the light beam is determined by using the geometric parameters:

[0075]

[0076] Wherein, d is the distance between the center points of the two MEMS micromirrors, l is the distance between the center of the second MEMS and the back pupil of the objective lens, θ x , θ y are the deflection angles of the final outgoing light beam in the X direction and the Y direction respectively, ω x1 , ω y1 , ω x2 , ω y2 are the deflection angles of the two MEMS micromirrors in the X direction and the Y direction respectively.

[0077] The deflection angle of the MEMS micro-mirror when performing the "S-shaped" scanning 21 is determined according to the above formula, and the MEMS micro-mirror control voltage waveform diagram is determined according to the corresponding relationship between the deflection angle of the MEMS micro-mirror and the driving voltage, as shown in the attached Figure 4 The control voltage required for the deflection of the MEMS micro-mirror is provided to complete the two-dimensional lateral scanning of the sample surface.

[0078] The Raman scattering light and the reflected light at each position on the measured sample 9 are collected by the measurement objective 7, and are divided into two beams by the Notch Filter 3, one of which is reflected by the Notch Filter 3 to reach the confocal detection system 16, and the other is transmitted through the Notch Filter 3 to enter the confocal Raman spectrum detection system 11.

[0079] The reflected light reaching the confocal detection system 16 is focused by the third converging lens 17, enters the confocal pinhole 18 at the focal point of the third converging lens 17, and is then received by the photodetector 19 and transmitted to the computer control and display system 26. The computer control and display system 26 processes and displays the obtained axial light intensity response curve 20, realizes the position detection and high-precision focusing of the sample, and then collects the Raman scattering light at the position where the focus point is located.

[0080] After the Raman scattering light is transmitted through the Notch Filter 3, it is focused by the first converging lens 12, enters the Raman spectrum collection pinhole 13, and is then received by the spectrum detector 15 after being converged by the second converging lens 14 and transmitted to the computer control and display system 26, realizing the detection and display of the Raman spectrum of the sample.

[0081] Figure 4 The control voltage waveform diagram of the two two-dimensional MEMS micro-mirrors in the embodiment of the present application, in the embodiment, the system can work in two modes of single-layer fast scanning and point-by-point focusing scanning. For a sample with a relatively flat surface, the system selects the single-layer fast scanning mode, the axial scanning system 8 drives the objective 7 to move to the focus position of the initial scanning point, sets the scanning waveform, scanning frequency and scanning step parameters of the double two-dimensional MEMS micro-mirror scanning system 4, and the computer control and display system 26 outputs the MEMS micro-mirror control voltage to drive the deflection of the MEMS micro-mirror to realize the fast scanning of the measurement beam, thereby completing the fast and high-sensitivity detection of the Raman spectrum of the sample surface.

[0082] For the sample with large surface relief, the axial scanning system 8 drives the objective lens 7 to move along the axial direction according to the set axial scanning waveform, the photodetector 19 synchronously detects the axial light intensity corresponding to the axial position, the computer control and display system 26 processes the collected axial position and light intensity information, obtains the position information of the sample at the point and performs high-precision focusing, the Raman spectrum detection system 11 detects the Raman scattered light at the focal position, the double two-dimensional MEMS micromirror scanning system 4 focuses the scanning light beam to the next scanning point, and prepares for the next axial scanning, and the cycle is repeated until all the points are scanned, so that the high spatial resolution Raman spectrum of the sample is obtained.

[0083] The above is only the preferred embodiment of the present application, and is not used to limit the present application, any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the protection scope of the present application. Other structures and principles are the same as the prior art, and will not be described here.

Claims

1. A high-sensitivity confocal Raman spectroscopy fast measurement method of two-dimensional MEMS micromirror scanning, characterized in that: Specifically comprising the following processes: Step one, the excitation light beam emitted by the light source system (1) passes through the light splitter (2) and the dichroic light splitting system (3), is reflected by the double two-dimensional MEMS micromirror scanning system (4), is collected by the measuring objective lens (7), and reaches the measured sample (9) to excite Raman scattering light and reflected light carrying the sample micro-area characteristics; Step two, the Raman scattering light and the reflected light are collected by the measuring objective lens (7), return along the original path of the double two-dimensional MEMS micromirror scanning system (4), are divided into two beams by the dichroic light splitting system (3), one of which is reflected by the dichroic light splitting system (3) to reach the confocal detection system (16), and the other of which passes through the dichroic light splitting system (3) to enter the confocal Raman spectrum detection system (11); Step three, the reflected light reaching the confocal detection system (16) is focused by the third converging lens (17), enters the confocal pinhole (18) at the focal point position of the third converging lens (17), and is then received by the photodetector (19); When the axial scanning system (8) drives the measuring objective lens (7) to perform axial scanning, the photodetector (19) obtains an axial light intensity response curve (20) varying with the axial position, and the axial focusing of the initial scanning point of the sample can be realized through the axial light intensity response curve (20); Step four, the Raman scattering light entering the confocal Raman spectrum detection system (11) is focused by the first converging lens (12), enters the Raman spectrum collection pinhole (13), is then focused by the second converging lens (14), and is received by the spectrum detector (15), thereby realizing high-sensitivity detection of the Raman spectrum of the sample; Step five, the double two-dimensional MEMS micromirror scanning system (4) controls the first MEMS micromirror (5) and the second MEMS micromirror (6) to perform deflection, and the functional relationship between the deflection angle of the MEMS micromirror and the scanning angle of the light beam is determined by using geometric parameters: wherein d is the distance between the center points of the two MEMS micromirrors, l is the distance between the center of the second MEMS and the back pupil of the objective, θ x , θ y are the deflection angles of the final outgoing light beam in the X and Y directions, respectively, ω x1 , ω y1 , ω x2 , ω y2 are the deflection angles of the two MEMS micromirrors in the X and Y directions, respectively; the measurement light beam is controlled to perform a "S-type" scan (21) on the surface of the measured sample (9), so as to realize the lateral fast scanning of the surface of the measured sample (9), and thus complete the fast and high-sensitivity detection of the Raman spectrum of the sample surface.

2. The fast measurement method of high sensitive confocal Raman spectroscopy with two-dimensional MEMS micromirror scanning according to claim 1, characterized in that: For a sample with relatively large surface undulation, a point-by-point focusing scanning mode can be used to obtain a high spatial resolution Raman spectrum image of the sample, and the specific steps are as follows: In step three, the reflected light reaching the confocal detection system (16) is focused by the third converging lens (17), enters the confocal pinhole (18) at the focal point position of the third converging lens (17), and is then received by the photodetector (19); when the axial scanning system (8) drives the measuring objective lens (7) to perform axial scanning, the photodetector (19) obtains an axial light intensity response curve (20) varying with the axial position, and the position detection and high-precision focusing of the sample can be realized through the axial light intensity response curve (20); In step four, after focusing, the measuring objective lens (7) is moved to the measured position of the sample to excite Raman scattering light, the Raman scattering light passes through the dichroic light splitting system (3), is focused by the first converging lens (12), enters the Raman spectrum collection pinhole (13), is then focused by the second converging lens (14), and is received by the spectrum detector (15), thereby realizing high spatial resolution Raman spectrum detection; The fifth step, the double two-dimensional MEMS micro-mirror scanning system (4) controls the first MEMS micro-mirror (5) and the second MEMS micro-mirror (6) to perform yawing, controls the measurement light beam focus point to move to the next scanning point of the measured sample (9), and repeats the above steps until the scanning of all the set points on the sample surface is completed.

3. The fast measurement method of high sensitive confocal Raman spectroscopy with two-dimensional MEMS micromirror scanning according to claim 2, characterized in that: The high-precision geometric morphology obtained by the confocal detection light path and the high-spatial-resolution Raman spectrum information obtained by the confocal Raman detection light path can realize high-spatial-resolution "graph and spectrum integration" imaging of the sample.

4. The high-sensitivity confocal Raman spectroscopy rapid measuring device for double two-dimensional MEMS micromirror scanning, used for realizing the high-sensitivity confocal Raman spectroscopy rapid measuring method for double two-dimensional MEMS micromirror scanning as claimed in claim 1, characterized in that: The device comprises a light source system (1) for generating an excitation light beam, a beam splitter (2), a dichroic beam splitting system (3), a double two-dimensional MEMS micro-mirror scanning system (4), a measurement objective lens (7), an axial scanning system (8), a measured sample (9), a confocal Raman spectrum detection system (11), a confocal detection system (16), and a computer control and display system (26); The light source system (1) comprises a laser (22), a converging objective lens (23), a spatial light filtering pinhole (24), and a collimating lens (25) for generating an excitation light beam; The double two-dimensional MEMS micro-mirror scanning system (4) comprises a first MEMS micro-mirror (5) and a second MEMS micro-mirror (6) for performing two-dimensional lateral scanning of the light beam; The axial scanning system (8) is connected with the measurement objective lens and is used for driving the objective lens to perform axial displacement; The Raman spectrum detection system (11) comprises a first converging lens (12), a Raman spectrum collection pinhole (13), a second converging lens (14), and a spectrum detector (15) for performing Raman spectrum detection; The confocal detection system (16) comprises a third converging lens (17), a confocal pinhole (18), and a photoelectric detector (19) for performing microscopic morphology measurement and high-precision axial focusing; The computer control and display system (26) is connected with the light source system (1), the double two-dimensional MEMS micro-mirror scanning system (4), the axial scanning system (8), the confocal Raman spectrum detection system (11), and the confocal detection system (16), and is the control center of the entire measurement device, used for adjusting the output power of the excitation light beam, controlling the scanning frequency, scanning angle, and scanning range of the MEMS micro-mirror, the scanning speed, scanning step, and scanning range of the axial scanning system, and processing and displaying the collected reflected light and Raman spectrum.

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