Optical fiber optical tweezers CARS micro-spectrum measurement system and method based on composite multi-core optical fiber

Abstract

The invention discloses an optical fiber optical tweezers CARS micro-spectrum measurement system and method based on a composite multi-core optical fiber. A unit comprises an optical fiber optical tweezers CARS laser source, a light source beam combining unit, a composite multi-core optical fiber coupling unit, the composite multi-core optical fiber, a composite multi-core optical fiber convergence unit and a signal collecting and processing unit. Pump ultrafast pulse light, Stokes ultrafast pulse light and capture ultrafast pulse light generated by the optical fiber optical tweezers CARS laser source are combined, coupled through the composite multi-core optical fiber coupling unit, enter the composite multi-core optical fiber for transmission, and then emitted and converged on a particle to be detected through the composite multi-core optical fiber convergence unit. The optical tweezers capture of the particles to be measured and the measurement of CARS signals are synchronously realized. The system can be miniaturized and integrated, real-time in-situ CARS signal measurement of a single tiny particle is realized, and the system has a wide application prospect in the fields of material analysis and biomedicine.

Description

Technical Field

[0001] The invention relates to the field of optical fiber optics and coherent Raman spectroscopy detection, and in particular to an optical fiber optical tweezers CARS microscopic spectrum measurement system and method. Background Art

[0002] Coherent anti-Stokes Raman Scattering (CARS) microspectroscopy measurement technology has the advantages of no need for fluorescent labeling, high detection sensitivity and unique chemical selective detection ability, and is widely used in the field of life sciences. The generation of CARS signals requires two pulsed lights with a frequency difference equal to the molecular vibration frequency of the measured particle to be incident on the same position of the measured particle at the same time, so as to achieve the resonant excitation of the CARS signal. At present, the detection of biological particles is mainly carried out in a liquid environment. The position of biological particles in the liquid environment will change continuously due to Brownian motion, and it is almost impossible to perform long-term stable CARS microspectroscopy measurement on them. The development of optical tweezers technology makes it possible to fix and manipulate particles in three-dimensional space without contact with lasers. After strong focusing, the laser beam forms a strong gradient force optical trap at the particle to be measured, which can suppress the Brownian motion of the particle to be measured in the liquid environment and achieve stable fixation of the particle to be measured. The combination of traditional optical tweezers technology and Raman scattering technology uses spatial optical path, and the optical path system is complex and cumbersome and has low stability. . Summary of the invention

[0003] In order to overcome the shortcomings of the prior art, the present invention aims to propose a fiber optic tweezers CARS micro-spectroscopy measurement system and method based on a composite multi-core optical fiber, and construct a related system in combination with an innovative composite multi-core optical fiber structure design to achieve real-time in-situ capture of tiny particles in the sample to be tested and perform CARS signal measurement.

[0004] In the first aspect, the present invention provides a fiber optic tweezers CARS micro-spectroscopy measurement system based on a composite multi-core optical fiber, comprising at least a tweezers CARS laser source 1, a light source beam combining unit, a composite multi-core optical fiber coupling unit 6, a composite multi-core optical fiber 7, a composite multi-core optical fiber converging unit 8, a filter 10, and a signal acquisition and processing system 11; wherein: the fiber optic tweezers CARS laser source 1 outputs a pump ultrafast pulse light 21, a Stokes ultrafast pulse light 22, and a capture ultrafast pulse light 23 with the same polarization state, the same repetition frequency, and adjustable pulse delay to the light source beam combining unit; the light beam combined by the light source beam combining unit is coupled into the composite multi-core optical fiber 7 through the composite multi-core optical fiber coupling unit 6, wherein the pump ultrafast pulse light 21 and the Stokes ultrafast pulse light 22 are coupled into the central air core of the composite multi-core optical fiber 7, and the composite multi-core optical fiber 7 adopts a multi-core The composite optical fiber structure is a composite optical fiber structure with a hollow anti-resonance structure, wherein the optical fiber structure is respectively a coating layer 31, an outer cladding 32, a cladding tube 33, and an air core 34 from the outside to the inside, and four solid cores 35 are distributed in the outer cladding 32. The captured ultrafast pulse light 23 is coupled into the solid core 35 of the composite multi-core optical fiber 7; the captured ultrafast pulse light 23 is converged by the composite multi-core optical fiber convergence unit 8 to form a gradient force optical trap to capture the particle to be measured 9; the pump ultrafast pulse light 21 and the Stokes ultrafast pulse light 22 are converged to the particle to be measured 9 by the composite multi-core optical fiber convergence unit 8, and the optical fiber optical tweezers CARS laser source 1 is adjusted so that the pump ultrafast pulse light 21 and the Stokes ultrafast pulse light 22 overlap in time to excite the CARS signal light; the CARS signal light passes through the filter 10 to filter out stray light, and is collected and processed by the signal acquisition and processing system 11.

[0005] In some embodiments, the light source beam combining unit further includes a first reflector 2, a first dichroic mirror 3, a second dichroic mirror 4 and a second reflector 5. The pump ultrafast pulse light 21 is reflected by the first reflector 2 and then combined with the Stokes ultrafast pulse light 22 at the first long-pass dichroic mirror 3. The capture ultrafast pulse light 23 is reflected by the second reflector 5 and then combined with the pump ultrafast pulse light 21 and the Stokes ultrafast pulse light 22 at the second long-pass dichroic mirror 4.

[0006] In some embodiments, the pump ultrafast pulse light 21 has the ability to continuously tune the optical wavelength and adjust the pulse delay, with a pulse width of 100 to 10000 fs, a central wavelength of 800 to 1015 nm, and a repetition frequency of 40 to 80 MHz;

[0007] In some embodiments, the Stokes ultrafast pulse light 22 has the capability of continuous tuning of the optical wavelength and pulse delay adjustment, with a pulse width of 100 to 10000 fs, a central wavelength of 1015 to 1070 nm, and a repetition frequency of 40 to 80 MHz;

[0008] In some embodiments, the captured ultrafast pulse light 23 has a fixed wavelength, a pulse width of 100 to 1000 fs, a central wavelength of 780 nm, and a repetition frequency of 40 to 80 MHz;

[0009] In some embodiments, the first long-pass dichroic mirror 3 transmits light with a wavelength greater than its cut-off wavelength and reflects light with a wavelength less than its cut-off wavelength, and its cut-off wavelength is greater than or equal to the wavelength tuning lower limit of the Stokes ultrafast pulse light 22, thereby transmitting the Stokes ultrafast pulse light 22 and reflecting the pump ultrafast pulse light 21;

[0010] In some embodiments, the second long-pass dichroic mirror 4 transmits light with a wavelength greater than its cut-off wavelength and reflects light with a wavelength less than its cut-off wavelength, and its cut-off wavelength is greater than or equal to the wavelength tuning lower limit of the pump ultrafast pulse light 21, thereby transmitting the Stokes ultrafast pulse light 22 and the pump ultrafast pulse light 21, and reflecting and capturing the ultrafast pulse light 23.

[0011] In a second aspect, the present invention provides a method for measuring CARS microscopic spectra using optical fiber tweezers based on a composite multi-core optical fiber, characterized in that it comprises:

[0012] Step 1: Use the fiber optical tweezers CARS laser source 1 to output the pump ultrafast pulse light 21, the Stokes ultrafast pulse light 22 and the capture ultrafast pulse light 23 with the same polarization state, the same repetition frequency and adjustable pulse delay, wherein the wavelengths of the Stokes ultrafast pulse light 21 and the pump ultrafast pulse light 22 are continuously tuned, and the CARS signal is excited after the wave number difference of the wavelengths of the two beams matches the molecular vibration frequency;

[0013] Step 2: The pump ultrafast pulse light 21 is reflected by the first reflector 2 and then combined with the Stokes ultrafast pulse light 22 at the first long-pass dichroic mirror 3; the capture ultrafast pulse light 23 is reflected by the second reflector 5 and then combined with the pump ultrafast pulse light 21 and the Stokes ultrafast pulse light 22 at the second long-pass dichroic mirror 4;

[0014] Step 3: The light beam after light source combination is coupled into the composite multi-core optical fiber 7 through the composite multi-core optical fiber coupling unit 6, wherein the pump ultrafast pulse light 21 and the Stokes ultrafast pulse light 22 are coupled into the central air core 34 of the composite multi-core optical fiber 7, and the capture ultrafast pulse light 23 is coupled into the solid core 35 of the composite multi-core optical fiber;

[0015] Step 4: The captured ultrafast pulse light 23 is converged by the composite multi-core optical fiber convergence unit 8 to form a gradient force optical trap to capture the particles to be detected;

[0016] Step 5: Converging the pump ultrafast pulse light 21 and the Stokes ultrafast pulse light 22 to the particle to be tested 9 through the composite multi-core optical fiber converging unit 8, and the two pulses overlap in space; adjusting the optical tweezers CARS laser source 1 to make the pulse time of the output pump ultrafast pulse light 21 and the Stokes ultrafast pulse light 22 overlap, and stimulate CARS signal light;

[0017] Step 6: The CARS signal light passes through the filter 10 to filter out stray light, and is collected and processed by the signal collection and processing system 11.

[0018] In the third aspect, the present invention provides a composite multi-core optical fiber structure, wherein the composite multi-core optical fiber 7 adopts a composite optical fiber structure consisting of a multi-core structure and a hollow anti-resonance structure, and its optical fiber structure from the outside to the inside comprises a coating layer 31, an outer cladding 32, a cladding tube 33, and an air core 34, and four solid cores 35 are distributed in the outer cladding 32.

[0019] Compared with the prior art, the present invention innovatively proposes a composite multi-core optical fiber as a transmission device for two probe beams and captured pulse light of CARS. The composite multi-core optical fiber 7 adopts a composite optical fiber structure design composed of a multi-core structure and a hollow anti-resonance structure. The optical fiber structure comprises a coating layer 31, an outer cladding 32, a cladding tube 33, and an air core 34 from the outside to the inside. Four solid cores 35 are distributed in the outer cladding 32 for transmitting the captured ultrafast pulse light 23. The air core 34 located in the center is used to transmit the pump ultrafast pulse light 21 and the Stokes ultrafast pulse light. Fast pulse light 22 eliminates the four-wave mixing background noise and pulse walk-off effects brought by solid optical fiber; it simultaneously realizes the optical tweezers capture of the particles to be tested and the CARS signal excitation detection. By combining fiber optic tweezers and fiber nonlinear spectroscopy technology, it greatly simplifies the instrument structure and improves the system integration, reducing the system cost; it significantly enhances the control ability and detection stability of the detection object, and can realize real-time in-situ CARS microscopic spectrum long-term tracking measurement of a single tiny particle in three-dimensional space, which is helpful to promote the application of CARS detection systems in biomedicine, life sciences and other fields. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 A schematic diagram of the architecture of a fiber optic tweezers CARS micro-spectroscopy measurement system based on a composite multi-core optical fiber according to the present invention;

[0021] Figure 2 This is the end face structure diagram of the composite multi-core optical fiber;

[0022] Figure 3 It is a structural diagram of a composite multi-core optical fiber convergence unit;

[0023] Figure 4 It is a schematic diagram of the overall process of a fiber optic tweezers CARS micro-spectroscopy measurement method based on a composite multi-core optical fiber of the present invention;

[0024] Reference numerals:

[0025] 1. Fiber optic tweezers CARS laser source, 2. First reflector, 3. First long-pass dichroic mirror, 4. Second long-pass dichroic mirror, 5. Second reflector, 6. Composite multi-core fiber coupling unit, 7. Composite multi-core fiber, 8. Composite multi-core fiber converging unit, 9. Particles to be measured, 10. Filter, 11. Signal acquisition and processing system;

[0026] 21. Pump ultrafast pulse light, 22. Stokes pulse light, 23. Capture pulse light;

[0027] 31. coating layer, 32. outer cladding layer, 33. cladding tube, 34. air core, 35. solid core;

[0028] 41. Central meta-lens unit, 42. Outer ring meta-lens unit. DETAILED DESCRIPTION

[0029] The technical solution proposed by the present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0030] The present invention proposes a fiber optic tweezers CARS micro-spectroscopy measurement unit and method based on a composite multi-core optical fiber. The specially designed composite multi-core optical fiber is used as a transmission device for CARS detection light and capture pulse light, which can simultaneously realize the capture of the measured particles and the measurement of CARS signals, simplify the system structure, improve the system integration, reduce the system cost, and realize the real-time in-situ CARS micro-spectroscopy measurement of a single tiny particle in three-dimensional space.

[0031] like Figure 1 As shown, in a fiber optic tweezers CARS micro-spectroscopy measurement system based on a composite multi-core optical fiber of the present invention, the system includes a fiber optic tweezers CARS laser source 1, a light source beam combining unit, a composite multi-core optical fiber coupling unit 6, a composite multi-core optical fiber 7, a composite multi-core optical fiber converging unit 8 and a signal acquisition and processing system 11.

[0032] like Figure 2As shown, the composite multi-core optical fiber 7 adopts a composite optical fiber structure design consisting of a multi-core structure and a hollow anti-resonance structure. The optical fiber structure is composed of a coating layer 31, an outer cladding 32, a cladding tube 33, and an air core 34 from the outside to the inside. Four solid cores 35 are distributed in the outer cladding 32 for transmitting the captured ultrafast pulse light 23. The air core 34 located in the center is used to transmit the pump ultrafast pulse light 21 and the Stokes ultrafast pulse light 22, eliminating the four-wave mixing background noise and pulse walk-off effects brought by the solid optical fiber. The typical length of the composite multi-core optical fiber 7 is in the range of 1 to 10 m.

[0033] Wherein: the fiber optical tweezers CARS laser source 1 outputs a pump ultrafast pulse light 21, a Stokes ultrafast pulse light 22 and a capture ultrafast pulse light 23 with the same polarization state, the same repetition frequency and adjustable pulse delay; the light source beam combining unit further comprises a first reflector 2, a first dichroic mirror 3, a second dichroic mirror 4 and a second reflector 5; the pump ultrafast pulse light 21 is combined with the Stokes ultrafast pulse light 22 at the first long-pass dichroic mirror 3 after being reflected by the first reflector 2, and the capture ultrafast pulse light 23 is combined with the pump ultrafast pulse light 21 and the Stokes ultrafast pulse light 22 at the second long-pass dichroic mirror 4 after being reflected by the second reflector 5; the combined light beam is coupled into the composite multi-core optical fiber 7 through the composite multi-core optical fiber coupling unit 6, wherein the pump ultrafast pulse light 21 and the Stokes ultrafast pulse light 22 are coupled into the composite multi-core optical fiber 7 located at the end face of the composite multi-core optical fiber 7 The air fiber core 34 at the center position, the captured ultrafast pulse light 23 is coupled into the solid fiber core 35 on the outer cladding 32 of the end face of the composite multi-core optical fiber 7; the captured ultrafast pulse light 23 is converged by the composite multi-core optical fiber convergence unit 8 to form a gradient force light trap to capture the particle 9 to be measured; the pump ultrafast pulse light 21 and the Stokes ultrafast pulse light 22 are converged to the particle 9 to be measured by the composite multi-core optical fiber convergence unit 8, and the fiber optical tweezers CARS laser source 1 is adjusted so that the pump ultrafast pulse light 21 and the Stokes ultrafast pulse light 22 overlap in time to excite the CARS signal light; the signal acquisition and processing unit collects the CARS signal light through photoelectric conversion, and performs denoising, baseline correction and normalization on the spectral signal; if necessary, the system is also provided with a filter 10, and the CARS signal light is filtered out of the stray light after passing through the filter 10, and then collected and processed by the signal acquisition and processing system 11.

[0034] The pump ultrafast pulse light 21 has the ability to continuously tune the optical wavelength and adjust the pulse delay, with a pulse width of 100 to 10000 fs, a central wavelength of 800 to 1015 nm, and a repetition frequency of 40 to 80 MHz;

[0035] The wavelength of the Stokes ultrafast pulse light 22 has the capability of continuous tuning and pulse delay adjustment, with a pulse width of 100 to 10000 fs, a central wavelength of 1015 to 1070 nm, and a repetition frequency of 40 to 80 MHz;

[0036] The captured ultrafast pulse light 23 has a fixed wavelength, a pulse width of 100 to 1000 fs, a central wavelength of 780 nm, and a repetition frequency of 40 to 80 MHz;

[0037] The first reflector 2 is used to reflect the pump ultrafast pulse light 21 .

[0038] The first long-pass dichroic mirror 3 transmits light with a wavelength greater than its cut-off wavelength and reflects light with a wavelength less than its cut-off wavelength, and its cut-off wavelength is greater than or equal to the wavelength tuning lower limit of the Stokes ultrafast pulse light 22, thereby transmitting the Stokes ultrafast pulse light 22 and reflecting the pump ultrafast pulse light 21.

[0039] The second long-pass dichroic mirror 4 transmits light with a wavelength greater than its cut-off wavelength and reflects light with a wavelength less than its cut-off wavelength, and its cut-off wavelength is greater than or equal to the wavelength tuning lower limit of the pump ultrafast pulse light 21, thereby transmitting the Stokes ultrafast pulse light 22 and the pump ultrafast pulse light 21, and reflecting and capturing the ultrafast pulse light 23.

[0040] The second reflector 5 is used to reflect the captured ultrafast pulse light 23 .

[0041] The composite multi-core optical fiber coupling unit 6 is composed of a glass lens and a meta-lens, wherein the glass lens is used to couple the pump ultrafast pulse light 21 and the Stokes ultrafast pulse light 22 into the central air core of the composite multi-core optical fiber 7, and the meta-lens is used to couple the captured ultrafast pulse light 23 into the solid core 35 of the composite multi-core optical fiber 7. The length of the composite multi-core optical fiber 7 is typically in the range of 1 to 10 m.

[0042] The signal acquisition and processing system 11 is composed of a highly sensitive photoelectric detector, a driving circuit, an acquisition circuit and a computer, and realizes the conversion of photoelectric signals and the acquisition and processing of electrical signals. Types of highly sensitive photoelectric detectors include photomultiplier tubes and single photon detectors.

[0043] like Figure 3 As shown, the composite multi-core optical fiber converging unit 8 is implemented by a meta-lens structure, and is composed of a central meta-lens unit 41 and an outer ring meta-lens unit 42. The central meta-lens unit 41 is used to converge the pump ultrafast pulse light 21 and the Stokes ultrafast pulse light 22, and the outer ring meta-lens unit 42 is used to converge the capture ultrafast pulse light 23.

[0044] The filter 10 is a bandpass filter that only allows CARS signal light to pass through and is used to filter out stray light;

[0045] The signal acquisition and processing system 11 is composed of a highly sensitive photoelectric detector, a driving circuit, an acquisition circuit and a computer, and realizes the conversion of photoelectric signals and the acquisition and processing of electrical signals. Types of highly sensitive photoelectric detectors include photomultiplier tubes and single photon detectors.

[0046] like Figure 4 As shown, a fiber optic tweezers CARS micro-spectroscopy measurement method based on a composite multi-core optical fiber of the present invention comprises the following steps:

[0047] Step 1: Use the fiber optical tweezers CARS laser source 1 to output the pump ultrafast pulse light 21, the Stokes ultrafast pulse light 22 and the capture ultrafast pulse light 23 with the same polarization state, the same repetition frequency and adjustable pulse delay, wherein the wavelengths of the Stokes ultrafast pulse light 21 and the pump ultrafast pulse light 22 are continuously tuned, and the CARS signal is excited after the wave number difference of the wavelengths of the two beams matches the molecular vibration frequency;

[0048] Step 2: The pump ultrafast pulse light 21 is reflected by the first reflector 2 and then combined with the Stokes ultrafast pulse light 22 at the first long-pass dichroic mirror 3; the capture ultrafast pulse light 23 is reflected by the second reflector 5 and then combined with the pump ultrafast pulse light 21 and the Stokes ultrafast pulse light 22 at the second long-pass dichroic mirror 4;

[0049] Step 3: The light beam after light source combination is coupled into the composite multi-core optical fiber 7 through the composite multi-core optical fiber coupling unit 6, wherein the pump ultrafast pulse light 21 and the Stokes ultrafast pulse light 22 are coupled into the central air core 34 of the composite multi-core optical fiber 7, and the capture ultrafast pulse light 23 is coupled into the outer ring core 35 of the composite multi-core optical fiber;

[0050] Step 4: The captured ultrafast pulse light 23 is converged by the composite multi-core optical fiber convergence unit 8 to form a gradient force optical trap to achieve the capture of the particles to be detected;

[0051] Step 5: The pump ultrafast pulse light 21 and the Stokes ultrafast pulse light 22 are converged to the particle to be tested 9 through the composite multi-core optical fiber convergence unit 8, the two pulses overlap in space and the convergence spot is less than 1 μm, and the optical tweezers CARS laser source 1 is adjusted to make the pulse time of the output pump ultrafast pulse light 21 and the Stokes ultrafast pulse light 22 overlap, and stimulate CARS signal light;

[0052] Step 6: The CARS signal light passes through the filter 10 to filter out stray light, and is collected and processed by the signal collection and processing system 11.

[0053] The above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention. The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications made without departing from the principle of the present invention should also be regarded as falling within the protection scope of the present invention.

Claims

1. A fiber optic tweezers CARS micro-spectroscopy measurement system based on a composite multi-core optical fiber, characterized in that: The optical fiber optical tweezers CARS laser source (1) comprises at least an optical tweezers CARS laser source (1), a light source beam combining unit, a composite multi-core optical fiber coupling unit (6), a composite multi-core optical fiber (7), a composite multi-core optical fiber converging unit (8) and a signal acquisition and processing unit (11); wherein: the optical fiber optical tweezers CARS laser source (1) outputs pump ultrafast pulse light (21), Stokes ultrafast pulse light (22) and capture ultrafast pulse light (23) with the same polarization state, the same repetition frequency and adjustable pulse delay to the optical source beam combining unit; the light beams combined by the optical source beam combining unit are coupled into the composite multi-core optical fiber (7) through the composite multi-core optical fiber coupling unit (6), wherein the pump ultrafast pulse light (21) and the Stokes ultrafast pulse light (22) are coupled into the central air core of the composite multi-core optical fiber (7), and the composite multi-core optical fiber (7) adopts a composite optical fiber structure composed of a multi-core structure and a hollow anti-resonance structure, wherein The optical fiber structure comprises, from outside to inside, a coating layer (31), an outer cladding layer (32), a cladding tube (33), and an air core (34), four solid cores (35) are distributed in the outer cladding layer (32), the captured ultrafast pulse light (23) is coupled into the solid core (35) of the composite multi-core optical fiber (7); the captured ultrafast pulse light (23) is converged by the composite multi-core optical fiber convergence unit (8) to form a gradient force optical trap to capture the particle to be measured (9); the pump ultrafast pulse light (21) and the Stokes ultrafast pulse light (22) are converged to the particle to be measured (9) by the composite multi-core optical fiber convergence unit (8), the optical fiber optical tweezers CARS laser source (1) is adjusted so that the pump ultrafast pulse light (21) and the Stokes ultrafast pulse light (22) overlap in time to excite CARS signal light; and the signal acquisition and processing unit (11) acquires and processes the CARS signal light.

2. The fiber optic tweezers CARS micro-spectroscopy measurement system based on a composite multi-core optical fiber according to claim 1, characterized in that: The light source beam combining unit further comprises a first reflector (2), a first dichroic mirror (3), a second dichroic mirror (4) and a second reflector (5); the pump ultrafast pulse light (21) is combined with the Stokes ultrafast pulse light (22) at the first long-pass dichroic mirror (3) after being reflected by the first reflector (2); the capture ultrafast pulse light (23) is combined with the pump ultrafast pulse light (21) and the Stokes ultrafast pulse light (22) at the second long-pass dichroic mirror (4) after being reflected by the second reflector (5).

3. The optical fiber tweezers CARS micro-spectroscopy measurement system based on a composite multi-core optical fiber according to claim 1, characterized in that: The pump ultrafast pulse light (21) has the capability of continuous tuning of optical wavelength and pulse delay adjustment, with a pulse width of 100 to 10000 fs, a central wavelength of 800 to 1015 nm, and a repetition frequency of 40 to 80 MHz.

4. The fiber optic tweezers CARS micro-spectroscopy measurement system based on a composite multi-core optical fiber according to claim 1, characterized in that: The Stokes ultrafast pulse light (22) has the capability of continuous tuning of optical wavelength and pulse delay adjustment, with a pulse width of 100 to 10000 fs, a central wavelength of 1015 to 1070 nm, and a repetition frequency of 40 to 80 MHz.

5. The fiber optic tweezers CARS micro-spectroscopy measurement system based on a composite multi-core optical fiber according to claim 1, characterized in that: The captured ultrafast pulse light (23) has a fixed wavelength, a pulse width of 100 to 1000 fs, a central wavelength of 780 nm, and a repetition frequency of 40 to 80 MHz.

6. The fiber optic tweezers CARS micro-spectroscopy measurement system based on a composite multi-core optical fiber according to claim 2, characterized in that: The first long-pass dichroic mirror (3) transmits light having a wavelength greater than its cut-off wavelength and reflects light having a wavelength less than its cut-off wavelength, wherein the cut-off wavelength is greater than or equal to the wavelength tuning lower limit of the Stokes ultrafast pulse light (22), thereby transmitting the Stokes ultrafast pulse light (22) and reflecting the pump ultrafast pulse light (21).

7. The fiber optic tweezers CARS micro-spectroscopy measurement system based on a composite multi-core optical fiber according to claim 2, characterized in that: The second long-pass dichroic mirror (4) transmits light having a wavelength greater than its cut-off wavelength and reflects light having a wavelength less than its cut-off wavelength, wherein the cut-off wavelength is greater than or equal to the wavelength tuning lower limit of the pump ultrafast pulse light (21), thereby transmitting the Stokes ultrafast pulse light (22) and the pump ultrafast pulse light (21), and reflecting and capturing the ultrafast pulse light (23).

8. A fiber optic tweezers CARS micro-spectroscopy measurement method based on a composite multi-core optical fiber implemented by a fiber optic tweezers CARS micro-spectroscopy measurement system based on a composite multi-core optical fiber according to any one of claims 1 to 7, characterized in that: include: Step 1: using a fiber optical tweezers CARS laser source (1) to output a pump ultrafast pulse light (21), a Stokes ultrafast pulse light (22) and a capture ultrafast pulse light (23) with the same polarization state, the same repetition frequency and adjustable pulse delay, wherein the wavelengths of the Stokes ultrafast pulse light (21) and the pump ultrafast pulse light (22) are continuously tuned, and the CARS signal is excited after the wave number difference of the wavelengths of the two beams matches the molecular vibration frequency; Step 2: After the pump ultrafast pulse light (21) is reflected by the first reflector (2), it is combined with the Stokes ultrafast pulse light (22) at the first long-pass dichroic mirror (3); after the capture ultrafast pulse light (23) is reflected by the second reflector (5), it is combined with the pump ultrafast pulse light 21 and the Stokes ultrafast pulse light (22) at the second long-pass dichroic mirror (4); Step 3: The light beam after the light source is combined is coupled into the composite multi-core optical fiber (7) through the composite multi-core optical fiber coupling unit (6), wherein the pump ultrafast pulse light (21) and the Stokes ultrafast pulse light (22) are coupled into the central air core (34) of the composite multi-core optical fiber (7), and the capture ultrafast pulse light (23) is coupled into the solid core (35) of the composite multi-core optical fiber; Step 4: The captured ultrafast pulse light (23) is converged through the composite multi-core optical fiber convergence unit (8) to form a gradient force optical trap to capture the particles to be detected; Step 5: Converging the pump ultrafast pulse light (21) and the Stokes ultrafast pulse light (22) to the particle to be detected (9) via the composite multi-core optical fiber converging unit (8), and the two pulses overlap in space; The optical tweezers CARS laser source (1) is adjusted so that the pulse times of the output pump ultrafast pulse light (21) and the Stokes ultrafast pulse light (22) overlap, thereby stimulating CARS signal light; Step 6: Use the acquisition and processing unit (11) to collect and process the CARS signal light signal.

9. A composite multi-core optical fiber structure, characterized in that: The composite multi-core optical fiber (7) adopts a composite optical fiber structure composed of a multi-core structure and a hollow anti-resonance structure, wherein the optical fiber structure comprises, from the outside to the inside, a coating layer (31), an outer cladding (32), a cladding tube (33), and an air core (34), and four solid cores (35) are distributed in the outer cladding (32).

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