Double-optical-comb coherent Raman spectrum background noise suppression system for probe light delay regulation and control

Abstract

A double-optical comb coherent Raman spectrum background noise suppression system for probe light delay regulation is characterized in that a first spectroscope for dividing laser emitted by an optical frequency comb light source module into probe light and pump light is arranged in a probe light delay regulation module, and an optical delay line is arranged to apply delay amount to the probe light; the characteristic that the attenuation time of coherent Raman spectrum signals is longer than that of background noise is utilized, detection light with delay amount is used for detection, the purpose of suppressing the background noise is achieved, the signal-to-noise ratio of a double-optical-comb coherent Raman spectrum measurement system is improved, and spectral signal distortion is suppressed.

Description

Technical Field

[0001] The present invention relates to a coherent Raman spectroscopy measurement technology, and in particular to a background noise suppression system of a dual-comb coherent Raman spectroscopy measurement technology based on detection light delay control. A first spectroscope is arranged in a detection light delay control module to divide laser light emitted by an optical frequency comb light source module into detection light and pump light, an optical delay line is arranged to apply a delay to the detection light, and the characteristic that the decay time of a coherent Raman spectroscopy signal is longer than that of a background noise is utilized. The detection light with a delay is used for detection, so as to achieve the purpose of suppressing background noise, thereby facilitating improving the signal-to-noise ratio of the dual-comb coherent Raman spectroscopy measurement system and suppressing spectral signal distortion. Background Art

[0002] Coherent Raman scattering is a Raman scattering technique based on nonlinear effects. This method uses the characteristics of the frequency difference in the excitation pulse matching the Raman energy level of the molecule to coherently excite the molecules in an area, thereby generating a coherent Raman signal that exceeds the spontaneous Raman effect signal intensity by 4 to 5 orders of magnitude. Coherent Raman spectroscopy signals reflect the molecular structural characteristics of substances, can provide rich "component-function" information, and have non-destructive and non-labeling detection capabilities. Therefore, it has broad application prospects in single-cell imaging and analysis, cell metabolism research, trace chemical identification, virus detection and identification, and other fields. The dual-comb coherent Raman spectroscopy method uses two optical comb light sources as pump light (also used as detection light) and Stokes light, respectively. On the basis of ensuring the high peak power pulses required for coherent Raman spectroscopy technology, combined with the dual-comb asynchronous sampling method, it breaks through the limitations of mechanical scanning methods and greatly improves the measurement speed.

[0003] The inventors understand that coherent Raman excitation is a third-order nonlinear effect, and the signal it generates is affected by background noise that does not carry molecular chemical information, which seriously affects the signal-to-noise ratio of the coherent Raman signal. At the same time, the coherent superposition of background noise and resonance signals will cause signal distortion, seriously affecting the accuracy of spectral data. The inventors believe that since the background noise signal mainly originates from the four-wave mixing process, the occurrence time is almost instantaneous, and the coherent Raman spectrum signal has a lifetime of the order of ps. Therefore, if a part of the pump light is separated as additional detection light, and the detection light delay is increased by setting an optical delay line, the coherent Raman spectrum signal after the background noise disappears can be detected. It can suppress the background noise, improve the signal-to-noise ratio of the coherent Raman spectrum measurement system, and suppress the distortion of the spectrum signal. At present, there is no system that uses delay to control the detection light to suppress the background noise of the dual-comb coherent Raman spectrum. In view of this, the inventors have completed the present invention. Summary of the invention

[0004] In view of the defects or shortcomings of the prior art, the present invention provides a background noise suppression system for a dual-comb coherent Raman spectroscopy measurement technology based on detection light delay control. A first spectroscope is provided in the detection light delay control module to divide the laser emitted by the optical frequency comb light source module into detection light and pump light, and an optical delay line is provided to apply a delay to the detection light. By utilizing the characteristic that the decay time of the coherent Raman spectroscopy signal is longer than the decay time of the background noise, detection is performed using the detection light with a delay, thereby achieving the purpose of suppressing the background noise, which is beneficial to improving the signal-to-noise ratio of the dual-comb coherent Raman spectroscopy measurement system and suppressing the distortion of the spectral signal.

[0005] The technical solution of the present invention is as follows:

[0006] The background noise suppression system of the dual-comb coherent Raman spectroscopy measurement technology based on the detection light delay regulation is characterized in that it includes an optical frequency comb light source module, a detection light delay regulation module, a delay compensation module, a delay monitoring module and a spectrum detection module connected in sequence, the optical frequency comb light source module combines two light beams with different frequencies and mutually perpendicular polarization directions into a first combined light beam, the detection light delay regulation module divides the first combined light beam into a first transmitted light and a first reflected light, the first transmitted light is directly transmitted to the delay compensation module, and the first reflected light is divided into a second transmitted light and a second reflected light. The second reflected light forms a delayed light and then combines with the second transmitted light to form a second combined light beam. The delay compensation module makes the first transmitted light form a delay compensation light and then combines with the second combined light beam to form a third combined light beam. The delay monitoring module divides the third combined light beam into a third reflected light and a third transmitted light. The third reflected light is used for delay monitoring in the delay monitoring module. The spectrum detection module uses the third transmitted light to detect the coherent Raman spectrum signal of the sample. The coherent Raman spectrum signal after the background noise disappears can be detected by the detection light with a delayed amount, thereby achieving background noise suppression.

[0007] The optical frequency comb light source module includes a first dichroic mirror, a first input side of the first dichroic mirror is connected to a first optical frequency comb, a second input side of the first dichroic mirror is connected to a second optical frequency comb via a first 1 / 2 wave plate, the first optical frequency comb and the second optical frequency comb are respectively connected to a reference source, and an output side of the first dichroic mirror is connected to the detection light delay control module.

[0008] The detection light delay control module includes a second dichroic mirror, the input side of the second dichroic mirror is connected to the output side of the first dichroic mirror, the transmission side of the second dichroic mirror is connected to the reflector in the delay compensation module, the reflection side of the second dichroic mirror is connected to the first beam splitter, the transmission side of the first beam splitter is connected to the first input side of the polarization beam splitter through the second reflector, the reflection side of the first beam splitter is connected to the second input side of the polarization beam splitter through the second 1 / 2 wave plate, the first reflector and the optical delay line in sequence, and the output side of the polarization beam splitter is connected to the first input side of the third dichroic mirror in the delay compensation module.

[0009] The delay compensation module includes an aspheric lens pair, the input side of the aspheric lens pair is connected to the reflector through a third reflector, the output side of the aspheric lens pair is connected to the second input side of a third dichroic mirror, and the output side of the third dichroic mirror is connected to the delay monitoring module.

[0010] The delay monitoring module includes a second beam splitter, the input side of the second beam splitter is connected to the output side of the third dichroic mirror, the transmission side of the second beam splitter is connected to the spectrum detection module, and the reflection side of the second beam splitter is connected to the oscilloscope via a first focusing lens, a barium borate crystal, a second focusing lens, a first filter and a photodetector in sequence.

[0011] The spectrum detection module includes a photomultiplier tube, a third focusing lens, a second filter, a second objective lens, a sample stage, a first objective lens and a fourth reflector connected to the transmission side of the second beam splitter.

[0012] The center frequency of the first optical frequency comb is 1030nm, and the repetition frequency is 100MHz. The center frequency of the second optical frequency comb is 1550nm, and the repetition frequency is 100MHz. The repetition frequency difference between the first optical frequency comb and the second optical frequency comb is adjustable, and the adjustable range of the repetition frequency difference is 0 to 100Hz. The reference signal frequency provided by the reference source is 100MHz.

[0013] The first filter is a low-pass filter with a cut-off wavelength of 700 nm.

[0014] The second filter is a bandpass filter with a transmission wavelength range of 750 to 900 nm.

[0015] The technical effects of the present invention are as follows: The present invention is a background noise suppression system for dual-comb coherent Raman spectroscopy measurement technology based on detection light delay control. By setting a first spectroscope in the detection light delay control module to divide the laser emitted by the optical frequency comb light source module into detection light and pump light, and setting an optical delay line to apply a delay to the detection light, the characteristic that the coherent Raman spectroscopy signal decay time is longer than the background noise decay time is utilized, and the detection light with a delay is used for detection to achieve the purpose of suppressing background noise, which is beneficial to improving the signal-to-noise ratio of the dual-comb coherent Raman spectroscopy measurement system and suppressing spectral signal distortion. The present invention is an innovative application of detection light delay control in the direction of background noise suppression in coherent Raman spectroscopy.

[0016] The advantages of the present invention over the prior art are as follows: (1) Compared with conventional coherent Raman scattering spectrum measurement devices, the use of detection light with a delay solves the problem of the difficulty in suppressing background noise caused by the four-wave mixing effect, thereby improving the signal-to-noise ratio of the spectral signal and reducing distortion. (2) A delay monitoring module is provided to monitor the delay between the pump light and the detection light and the Stokes light, respectively, to provide a basis for delay control. (3) By using an optical delay line to apply a delay, the delay adjustment can be achieved at the highest fs level, and the delay control is more precise. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of the structure of the dual-comb coherent Raman spectroscopy background noise suppression system for implementing the detection light delay control of the present invention. Figure 1 The system includes an optical frequency comb light source module, a detection light delay control module, a delay compensation module, a delay monitoring module and a spectrum detection module which are connected in sequence.

[0018] The reference numerals are as follows: 1-first optical frequency comb; 2-second optical frequency comb; 3-reference source; 4-first 1 / 2 wave plate; 5-first dichroic mirror (in the optical frequency comb light source module, the double light beams are combined into the first combined light beam, and the first combined light beam is transmitted to the detection light delay control module); 6-second dichroic mirror (in the detection light delay control module, the first combined light beam is divided into the first transmitted light, i.e., Stokes light, and the first reflected light, and the first transmitted light is directly transmitted to the delay compensation module, and the first reflected light is shaped after light splitting and delay control). =The first reflected light is divided into a pump light and a delayed light and then transmitted to the delay compensation module); 7-the first beam splitter (splits the first reflected light into a second reflected light, i.e., the detection light, and a second transmitted light, i.e., the pump light); 8-the second 1 / 2 wave plate; 9-the first reflector; 10-the optical delay line (applies a delay amount to form a delayed light, i.e., the detection light with a delay amount); 11-the second reflector; 12-the polarization beam splitter (combines the delayed light with the second reflected light to form a second combined light beam and transmits it to the delay compensation module); 13-the retroreflector (forms the delay compensation light) ; 14-third reflector; 15-aspheric lens pair; 16-third dichroic mirror (combines the second combined light beam with the delay compensation light into a third combined light beam and transmits it to the delay monitoring module); 17-oscilloscope; 18-photodetector; 19-first filter; 20-second focusing lens; 21-barium borate crystal (generates the sum frequency signal of the pump light and the Stokes light, and the sum frequency signal of the detection light and the Stokes light); 22-first focusing lens; 23-second spectroscope (combines the third combined light beam with the delay compensation light into a third combined light beam and transmits it to the delay monitoring module); The combined light beam is divided into a third reflected light and a third transmitted light, the third transmitted light is directly transmitted to the spectrum detection module, and the third reflected light enters the photodetector through the barium borate crystal); 24-photomultiplier tube (detects the coherent Raman spectrum signal of the sample, and the detection light with a delayed amount can detect the coherent Raman spectrum signal after the background noise disappears, thereby achieving background noise suppression); 25-third focusing lens; 26-second filter; 27-second objective lens; 28-sample stage; 29-first objective lens; 30-fourth reflecting mirror. DETAILED DESCRIPTION

[0019] Below is the attached figure ( Figure 1 ) and Examples illustrate the present invention.

[0020] Figure 1 The schematic diagram is a schematic diagram of the structure of the dual-comb coherent Raman spectroscopy background noise suppression system for implementing the detection light delay control of the present invention. Figure 1As shown, a background noise suppression system of dual-optical comb coherent Raman spectroscopy measurement technology based on detection light delay regulation includes an optical frequency comb light source module, a detection light delay regulation module, a delay compensation module, a delay monitoring module and a spectrum detection module connected in sequence, wherein the optical frequency comb light source module combines two light beams with different frequencies and mutually perpendicular polarization directions into a first combined light beam, the detection light delay regulation module divides the first combined light beam into a first transmitted light and a first reflected light, the first transmitted light is directly transmitted to the delay compensation module, the first reflected light is divided into a second transmitted light and a second reflected light, and the first The two reflected lights form delayed light and then combine with the second transmitted light to form a second combined light beam. The delay compensation module makes the first transmitted light form delay compensation light and then combine with the second combined light beam to form a third combined light beam. The delay monitoring module divides the third combined light beam into a third reflected light and a third transmitted light. The third reflected light is used for delay monitoring in the delay monitoring module. The spectrum detection module uses the third transmitted light to detect the coherent Raman spectrum signal of the sample. The coherent Raman spectrum signal after the background noise disappears can be detected by the detection light with a delayed amount, thereby achieving background noise suppression.

[0021] The optical frequency comb light source module includes a first dichroic mirror 5, a first input side of the first dichroic mirror 5 is connected to a first optical frequency comb 1, a second input side of the first dichroic mirror 5 is connected to a second optical frequency comb 2 via a first 1 / 2 wave plate 4, the first optical frequency comb 1 and the second optical frequency comb 2 are respectively connected to a reference source 3, and an output side of the first dichroic mirror 5 is connected to the detection light delay control module. The detection light delay control module includes a second dichroic mirror 6, the input side of the second dichroic mirror 6 is connected to the output side of the first dichroic mirror 5, the transmission side of the second dichroic mirror 6 is connected to the reflector 13 in the delay compensation module, the reflection side of the second dichroic mirror 6 is connected to the first beam splitter 7, the transmission side of the first beam splitter 7 is connected to the first input side of the polarization beam splitter 12 through the second reflector 11, the reflection side of the first beam splitter 7 is connected to the second input side of the polarization beam splitter 12 through the second 1 / 2 wave plate 8, the first reflector 9 and the optical delay line 10 in sequence, and the output side of the polarization beam splitter 12 is connected to the first input side of the third dichroic mirror 16 in the delay compensation module.

[0022] The delay compensation module includes an aspheric lens pair 15, the input side of the aspheric lens pair 15 is connected to the reflector 13 through the third reflector 14, the output side of the aspheric lens pair 15 is connected to the second input side of the third dichroic mirror 16, and the output side of the third dichroic mirror 16 is connected to the delay monitoring module. The delay monitoring module includes a second beam splitter 23, the input side of the second beam splitter 23 is connected to the output side of the third dichroic mirror 16, the transmission side of the second beam splitter 23 is connected to the spectrum detection module, and the reflection side of the second beam splitter 23 is connected to the oscilloscope 17 through the first focusing lens 22, the barium borate crystal 21, the second focusing lens 20, the first filter 19 and the photodetector 18 in sequence. The spectrum detection module includes a photomultiplier tube 24, and the photomultiplier tube 24 is connected to the transmission side of the second beam splitter 23 through the third focusing lens 25, the second filter 26, the second objective lens 27, the sample stage 28, the first objective lens 29 and the fourth reflector 30 in sequence.

[0023] The center frequency of the first optical frequency comb 1 is 1030nm, the repetition frequency is 100MHz, the center frequency of the second optical frequency comb 2 is 1550nm, the repetition frequency is 100MHz, the repetition frequency difference between the first optical frequency comb 1 and the second optical frequency comb 2 is adjustable, and the adjustable range of the repetition frequency difference is 0-100Hz; the reference signal frequency provided by the reference source 3 is 100MHz. The first filter 19 is a low-pass filter with a cut-off wavelength of 700nm. The second filter 26 is a band-pass filter with a transmission wavelength range of 750-900nm.

[0024] A dual-comb coherent Raman spectroscopy background noise suppression system with detection light delay control is disclosed. A first spectroscope is provided in a detection light delay control module to split the laser light emitted by an optical frequency comb light source module into detection light and pump light, and an optical delay line is provided to apply a delay to the detection light. The characteristic that the decay time of coherent Raman spectroscopy signal is longer than that of background noise is utilized, and detection is performed using the detection light with a delay, so as to achieve the purpose of suppressing background noise, thereby facilitating improving the signal-to-noise ratio of the dual-comb coherent Raman spectroscopy measurement system and suppressing spectral signal distortion.

[0025] refer to Figure 1 As shown, a dual-optical comb coherent Raman spectroscopy background noise suppression system with detection light delay control includes an optical frequency comb light source module, a detection light delay control module, a delay compensation module, a delay monitoring module and a spectrum detection module. A first beam splitter 7 is arranged in the detection light delay control module to split the laser emitted by the optical frequency comb light source module into detection light and pump light, and an optical delay line 10 is arranged to apply a delay to the detection light. The detection light with the delay and the pump light are coupled by a polarization beam splitter 12 and then act on the sample together with the Stokes light generated by the second optical frequency comb 2 to detect a coherent Raman signal with suppressed background noise.

[0026] The optical frequency comb light source module includes a first optical frequency comb 1, a second optical frequency comb 2, a first 1 / 2 wave plate 4 and a reference source 3. The laser emitted by the second optical frequency comb 2 is polarized by the first 1 / 2 wave plate 4 and then combined with the laser emitted by the first optical frequency comb through a first dichroic mirror 5 to enter the detection light delay control module; the reference source 3 is respectively connected to the first optical frequency comb 1 and the second optical frequency comb 2 to achieve repetition frequency locking of the first optical frequency comb 1 and the second optical frequency comb 2.

[0027] Specifically, in the optical frequency comb light source module, the center frequency of the first optical frequency comb 1 is 1030 nm, and the repetition frequency is 100 MHz; the center frequency of the second optical frequency comb 2 is 1550 nm, and the repetition frequency is 100 MHz; the repetition frequency difference between the first optical frequency comb 1 and the second optical frequency comb 2 is adjustable, and the adjustable range of the repetition frequency difference is 0 to 100 Hz.

[0028] The reference signal frequency provided by the reference source 3 is 100 MHz; the output lasers of the first optical frequency comb 1 and the second optical frequency comb 2 in the optical frequency comb light source module are both linearly polarized light, and the polarization direction of the second optical frequency comb output laser after passing through the first 1 / 2 wave plate 4 is perpendicular to the polarization direction of the first optical frequency comb 1.

[0029] The detection light delay control module includes a second dichroic mirror 6, a first beam splitter 7, a second 1 / 2 wave plate 8, an optical delay line 10 and a polarization beam splitter 12. The second dichroic mirror 6 is connected to the transmission beam of the first dichroic mirror 5. The transmission beam of the second dichroic mirror 6 is incident on the delay compensation module. The reflection beam of the second dichroic mirror 6 is connected to the first beam splitter 7. The reflection beam of the first beam splitter 7 is sequentially passed through the second 1 / 2 wave plate 8, the first reflector 9 and the optical delay line 10 to form a detection light with a delay amount and then incident on the polarization beam splitter 12. The transmission beam of the second dichroic mirror 8 passes through the second reflector 11 and then passes through the polarization beam splitter 12 to be combined with the detection light beam with the delay amount and then incident on the delay compensation module.

[0030] Specifically, the transmission and reflection ratio of the first beam splitter 7 in the detection light delay control module is 70:30, and the polarization direction of the transmission beam of the first beam splitter 7 after passing through the second 1 / 2 wave plate 8, the first reflector 9 and the optical delay line 10 is perpendicular to the polarization direction of the transmission beam of the first beam splitter 7.

[0031] The delay compensation module includes a reflector 13 and an aspheric lens pair 14, which are used to compensate the delay of the Stokes light to be consistent with the pump light; the transmission beam of the second dichroic mirror 6 passes through the reflector 13, the third reflector 14, and the aspheric lens pair 15 in sequence, and is coupled with the transmission beam of the polarization beam splitter 12 through the third dichroic mirror 16 and is injected into the delay monitoring module.

[0032] The delay monitoring module includes a barium borate crystal 21, a first filter 19, a photodetector 18 and an oscilloscope 17. The transmission beam of the third dichroic mirror 16 is incident on the second beam splitter 23. The reflection beam of the second beam splitter 23 is converged on the barium borate crystal 21 by the first focusing lens 22 and then collimated by the second focusing lens 20. After passing through the first filter 19, it is incident on the photodetector 18. The photodetector 18 is connected to the oscilloscope 17 to detect the delay of the laser emitted by the first optical frequency comb and the second optical frequency comb. Specifically, the first filter 19 in the delay monitoring module is a low-pass filter with a cutoff wavelength of 700nm.

[0033] The spectrum detection module includes a first objective lens 29, a second objective lens 27, a sample stage 28, a second filter 26 and a photomultiplier tube 24. The transmission beam of the second beam splitter 23 passes through a fourth reflector 30, the first objective lens 29, the sample stage 28, the second objective lens 27, the second filter 26, and a third focusing lens 25 in sequence, and then enters the photomultiplier tube 24 to detect the sample coherent Raman spectrum signal. Specifically, the second filter 26 in the spectrum detection module is a bandpass filter with a transmission wavelength range of 750 to 900 nm.

[0034] Specifically, the laser emitted by the optical frequency comb light source module is divided into two beams by the second dichroic mirror 6 in the detection light delay control module. The wavelength of the reflected beam of the second dichroic mirror 6 is shorter, and the wavelength of the transmitted beam of the second dichroic mirror 6 is longer, which is used as Stokes light. The reflected beam of the second dichroic mirror 6 is divided into two parts after being split by the first beam splitter 7. The reflected beam of the first beam splitter 7 is used as the detection light and obtains a certain delay after passing through the optical delay line 10; the transmitted beam of the second dichroic mirror 6 is coupled with the delayed detection light through the polarization beam splitter 12 as the pump light and is injected into the delay compensation module. The delay compensation module receives the Stokes light, compensates the delay between the Stokes light and the pump light through the reflector 13, and then injects the combined beam with the pump light and the delayed detection light into the delay monitoring module through the third dichroic mirror 16. The transmitted light of the third dichroic mirror 16 is injected into the second beam splitter 23 in the delay detection module. The reflected beam of the second spectroscope 23 reacts with the barium borate crystal to generate a sum-frequency signal of the pump light and the Stokes light and a sum-frequency signal of the detection light and the Stokes light, respectively, which are received by the photodetector 18 and displayed by the oscilloscope 17. By adjusting the delay amount applied by the optical delay line 10, the delay of the sum-frequency signal of the pump light and the Stokes light and the sum-frequency signal of the detection light and the Stokes light is observed to several ps, so as to achieve precise control of the detection light delay. The transmitted beam of the second spectroscope 23 is injected into the spectrum detection module to detect the coherent Raman spectrum signal of the sample. Since the lifetime of the coherent Raman spectrum signal is longer than the background noise, the detection light with the delay amount can detect the coherent Raman spectrum signal after the background noise disappears, thereby achieving background noise suppression.

[0035] The contents not described in detail in the specification of the present invention belong to the prior art known to the professional and technical personnel in the field. It is pointed out here that the above description helps those skilled in the art to understand the invention, but does not limit the protection scope of the invention. Any equivalent replacement, modification and / or simplification of the above description without departing from the essence of the invention falls within the protection scope of the invention.

Claims

1. A background noise suppression system based on dual-comb coherent Raman spectroscopy measurement technology with detection light delay control, characterized in that: The invention comprises an optical frequency comb light source module, a detection light delay control module, a delay compensation module, a delay monitoring module and a spectrum detection module connected in sequence, wherein the optical frequency comb light source module combines two light beams with different frequencies and mutually perpendicular polarization directions into a first combined light beam, the detection light delay control module divides the first combined light beam into a first transmitted light beam and a first reflected light beam, the first transmitted light beam is directly transmitted to the delay compensation module, the first reflected light beam is divided into a second transmitted light beam and a second reflected light beam, the second reflected light beam is combined with the second transmitted light beam after forming a delay light beam to form a second combined light beam, the delay compensation module makes the first transmitted light beam form a delay compensation light beam and then combine with the second combined light beam to form a third combined light beam, the delay monitoring module divides the third combined light beam into a third reflected light beam and a third transmitted light beam, the third reflected light beam is used for delay monitoring in the delay monitoring module, the spectrum detection module uses the third transmitted light beam to detect the coherent Raman spectrum signal of the sample, and the coherent Raman spectrum signal after the background noise disappears can be detected by the detection light with a delay amount, thereby realizing background noise suppression.

2. The background noise suppression system of the dual-comb coherent Raman spectroscopy measurement technology based on detection light delay control according to claim 1 is characterized in that: The optical frequency comb light source module includes a first dichroic mirror, a first input side of the first dichroic mirror is connected to a first optical frequency comb, a second input side of the first dichroic mirror is connected to a second optical frequency comb via a first 1 / 2 wave plate, the first optical frequency comb and the second optical frequency comb are respectively connected to a reference source, and an output side of the first dichroic mirror is connected to the detection light delay control module.

3. The background noise suppression system of the dual-comb coherent Raman spectroscopy measurement technology based on detection light delay control according to claim 1 is characterized in that: The detection light delay control module includes a second dichroic mirror, the input side of the second dichroic mirror is connected to the output side of the first dichroic mirror, the transmission side of the second dichroic mirror is connected to the reflector in the delay compensation module, the reflection side of the second dichroic mirror is connected to the first beam splitter, the transmission side of the first beam splitter is connected to the first input side of the polarization beam splitter through the second reflector, the reflection side of the first beam splitter is connected to the second input side of the polarization beam splitter through the second 1 / 2 wave plate, the first reflector and the optical delay line in sequence, and the output side of the polarization beam splitter is connected to the first input side of the third dichroic mirror in the delay compensation module.

4. The background noise suppression system of the dual-comb coherent Raman spectroscopy measurement technology based on detection light delay control according to claim 1, characterized in that: The delay compensation module includes an aspheric lens pair, the input side of the aspheric lens pair is connected to the reflector through a third reflector, the output side of the aspheric lens pair is connected to the second input side of a third dichroic mirror, and the output side of the third dichroic mirror is connected to the delay monitoring module.

5. The background noise suppression system of the dual-comb coherent Raman spectroscopy measurement technology based on detection light delay control according to claim 1, characterized in that: The delay monitoring module includes a second beam splitter, the input side of the second beam splitter is connected to the output side of the third dichroic mirror, the transmission side of the second beam splitter is connected to the spectrum detection module, and the reflection side of the second beam splitter is connected to the oscilloscope via a first focusing lens, a barium borate crystal, a second focusing lens, a first filter and a photodetector in sequence.

6. The background noise suppression system of the dual-comb coherent Raman spectroscopy measurement technology based on detection light delay control according to claim 1, characterized in that: The spectrum detection module includes a photomultiplier tube, a third focusing lens, a second filter, a second objective lens, a sample stage, a first objective lens and a fourth reflector connected to the transmission side of the second beam splitter.

7. The background noise suppression system of the dual-comb coherent Raman spectroscopy measurement technology based on detection light delay control according to claim 1, characterized in that: The center frequency of the first optical frequency comb is 1030nm, and the repetition frequency is 100MHz. The center frequency of the second optical frequency comb is 1550nm, and the repetition frequency is 100MHz. The repetition frequency difference between the first optical frequency comb and the second optical frequency comb is adjustable, and the adjustable range of the repetition frequency difference is 0 to 100Hz. The reference signal frequency provided by the reference source is 100MHz.

8. The background noise suppression system of the dual-comb coherent Raman spectroscopy measurement technology based on detection light delay control according to claim 5, characterized in that: The first filter is a low-pass filter with a cut-off wavelength of 700 nm.

9. The background noise suppression system of the dual-comb coherent Raman spectroscopy measurement technology based on detection light delay control according to claim 6, characterized in that: The second filter is a bandpass filter with a transmission wavelength range of 750 to 900 nm.

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