CN115753728B - Double-pulse stimulated Fourier transform coherent anti-Stokes Raman spectroscopy detection system - Google Patents

Abstract

The application relates to a double-pulse stimulated Fourier transform coherent anti-Stokes Raman spectrum detection system. The system comprises: the light source structure is used for generating a first Stokes pulse and a first pumping pulse, and adjusting the first Stokes pulse to obtain a second Stokes pulse so as to enable the Stokes pulse and the central wavelength of the pumping pulse to be separated by a preset interval; the beam combining structure is used for adjusting the first pump pulse to obtain a second pump pulse so as to enable the Stokes pulse to be matched with the time domain and the focus of the pump pulse, and combining the second Stokes pulse and the second pump pulse to obtain a first combined pulse; the copying structure is used for copying the first combined pulse to obtain a second combined pulse and a third combined pulse with relative delay; and the detection structure is used for exciting the target detection sample by adopting the second combined pulse and the third combined pulse and determining the detection result of the target detection sample. The method enables the detectable wave number range to be flexible and controllable.

Description

Double-pulse stimulated Fourier transform coherent anti-Stokes Raman spectroscopy detection system

Technical Field

The present application relates to the technical field of spectral detection, and in particular to a dual-pulse stimulated Fourier transform coherent anti-Stokes Raman spectroscopy detection system.

Background technique

With the development of microscopic imaging technology, Fourier transform coherent anti-Stokes Raman scattering spectroscopy microscopic imaging technology has emerged.

At present, the material structure composition information of tissue samples is usually excited and detected by using the impact-stimulated Fourier transform coherent anti-Stokes Raman spectroscopy detection method.

However, using the above method, the spectral coverage is concentrated in the area with lower wavenumbers, and the detection wavenumber area is limited.

Summary of the invention

Based on this, it is necessary to provide a dual-pulse stimulated Fourier transform coherent anti-Stokes Raman spectroscopy detection system to address the above-mentioned technical problems, which can make the detectable wavenumber region flexibly controllable.

The present application provides a dual-pulse stimulated Fourier transform coherent anti-Stokes Raman spectroscopy detection system, which includes a light source structure, a beam combining structure, a replication structure and a detection structure;

A light source structure for generating a first Stokes pulse and a first pump pulse, and adjusting the first Stokes pulse to obtain a second Stokes pulse so that the central wavelengths of the Stokes pulse and the pump pulse are separated by a preset interval;

A beam combining structure, used for adjusting the first pump pulse to obtain the second pump pulse, so that the Stokes pulse matches the pump pulse in both time domain and focus, and combining the second Stokes pulse and the second pump pulse to obtain the first combined pulse;

A replication structure, used for replicating the first combined pulse to obtain a second combined pulse and a third combined pulse with relative delay;

The detection structure is used to excite the target detection sample using the second combined pulse and the third combined pulse to determine the detection result of the target detection sample.

In one embodiment, the light source structure includes a pulse generating device, a light splitting device and a wavelength adjusting device;

A pulse generating device, used for generating original pulses;

A spectrometer is used to perform spectroscopic processing on the original pulse to obtain a first Stokes pulse and a first pump pulse;

The wavelength adjustment device is used to adjust the wavelength of the first Stokes pulse to obtain the second Stokes pulse.

In one embodiment, the optical splitter device includes a half-wave plate and a polarization beam splitter;

A half-wave plate is used to adjust the polarization direction of the original pulse to obtain an adjusted pulse;

The polarization beam splitter is used to perform beam splitting processing on the adjustment pulse to obtain a first Stokes pulse and a first pump pulse.

In one of the embodiments, the beam combining structure includes a time domain adjustment component, a focus adjustment component and a beam combiner;

A time domain adjustment component, used for performing time domain adjustment on the first pump pulse to obtain a pump pulse after time domain adjustment;

A focus adjustment component, used for adjusting the focus position of the pump pulse after time domain adjustment to obtain a second pump pulse;

The beam combiner is used to combine the second Stokes pulse and the second pump pulse to obtain a first combined pulse.

In one of the embodiments, the time domain adjustment assembly includes a first reflector, a second reflector, a third reflector, and a corner mirror;

a first reflector, configured to reflect the first pump pulse to a second reflector;

a second reflector, for reflecting the pump pulse reflected by the first reflector to the corner mirror;

an angle mirror for reflecting the pump pulse reflected by the second reflector to a third reflector;

The third reflecting mirror is used to reflect the pump pulse reflected by the corner mirror to the focus adjustment component.

In one embodiment, the focus adjustment assembly includes a first lens, a second lens and a fourth reflector; the optical axes of the first lens and the second lens are located on the same straight line;

The first lens and the second lens are used to adjust the focal position of the pump pulse to obtain a second pump pulse;

The fourth reflector is used to reflect the second pump pulse to the beam combiner.

In one embodiment, the replica structure includes a beam splitter, a first delay component, and a second delay component;

A beam splitter, used for replicating the first combined pulse to obtain a first replica pulse and a second replica pulse;

A first delay component, used for performing reflection processing on the first replica pulse to obtain a second combined pulse;

A second delay component, used for performing delay processing on the second replica pulse to obtain a third combined pulse;

The beam splitter is also used for merging the second combined pulse and the third combined pulse, and emitting the combined second combined pulse and the third combined pulse to the detection structure.

In one embodiment, the second delay assembly includes a fifth reflector, a curved mirror, and a resonant scanning mirror;

The second replica pulse is reflected by the fifth reflecting mirror, the curved mirror, the resonant scanning mirror, the curved mirror and the fifth reflecting mirror in sequence and returns to the beam splitter.

In one embodiment, the detection structure includes a first objective lens, a second objective lens and a detection assembly;

A first objective lens is used to excite the target detection sample using the second combined pulse and the third combined pulse to obtain a first excitation light;

A second objective lens is used to collect the first excitation light to obtain a second excitation light;

The detection component is used to determine the detection result of the target detection sample according to the second excitation light.

In one embodiment, the detection assembly includes a filter and a detector;

A filter, used for filtering the second excitation light to obtain a third excitation light;

The detector is used to perform detection processing according to the third excitation light to determine the detection result of the target detection sample.

The above-mentioned dual-pulse stimulated Fourier transform coherent anti-Stokes Raman spectroscopy detection system includes a light source structure, a beam combining structure, a replica structure and a detection structure; the light source structure is used to generate a first Stokes pulse and a first pump pulse, and adjust the first Stokes pulse to obtain a second Stokes pulse so that the central wavelengths of the Stokes pulse and the pump pulse are separated by a preset interval; the beam combining structure is used to adjust the first pump pulse to obtain the second pump pulse so that the Stokes pulse and the pump pulse are matched in time domain and focus, and the second Stokes pulse and the second pump pulse are combined to obtain a first combined pulse; the replica structure is used to replicate the first combined pulse to obtain a second combined pulse and a third combined pulse with relative delay; the detection structure is used to use the second combined pulse and the third combined pulse to excite the target detection sample and determine the detection result of the target detection sample. The embodiment of the present application excites, collects and detects the target detection sample through a dual-pulse stimulated Fourier transform coherent anti-Stokes Raman spectroscopy detection system to obtain Raman spectral information of molecular oscillations. Since the light source structure can generate dual pulses and the spacing between the central wavelengths of the dual pulses can be adjusted, the coverage of the spectrum can be expanded to areas with higher wave numbers instead of being limited to areas with lower wave numbers. The detectable wave number range is flexible and controllable, thereby realizing the excitation and detection of molecular oscillations in any wave number area.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a frequency domain principle diagram of an impact-stimulated Fourier transform coherent anti-Stokes Raman spectroscopy detection method in one embodiment;

FIG2 is a schematic diagram of the structure of a double-pulse stimulated Fourier transform coherent anti-Stokes Raman spectroscopy detection system in one embodiment;

FIG3 is a schematic diagram of a light source structure in one embodiment;

FIG4 is a schematic diagram of the structure of a spectrometer in one embodiment;

FIG5 is a schematic diagram of a beam combining structure in one embodiment;

FIG6 is a schematic diagram of the structure of a time domain adjustment component in one embodiment;

FIG7 is a schematic diagram of the structure of a focus adjustment component in one embodiment;

FIG8 is a frequency domain schematic diagram of a coherent anti-Stokes scattering signal generated when a double pulse interacts with a sample in one embodiment;

FIG9 is a time domain schematic diagram of a coherent anti-Stokes scattering signal generated when a double pulse interacts with a sample in one embodiment;

FIG10 is a schematic diagram of a replication structure in one embodiment;

FIG11 is a schematic diagram of the structure of a second delay component in one embodiment;

FIG12 is a schematic diagram of a dual-pulse stimulated Fourier transform coherent anti-Stokes Raman spectroscopy detection system in one embodiment;

FIG13 is a schematic diagram of a detection structure in one embodiment;

FIG. 14 is a schematic diagram of the structure of a detection component in one embodiment.

Detailed ways

In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

At present, the impact-stimulated Fourier transform coherent anti-Stokes Raman spectroscopy detection method is usually used to excite and detect the material structure composition information of tissue samples. As shown in Figure 1, the spectral coverage of the impact-stimulated Fourier transform coherent anti-Stokes Raman scattering is concentrated in the lower wave number area, but the higher wave number area contains rich molecular oscillation information, so the impact-stimulated Fourier transform coherent anti-Stokes Raman spectroscopy detection method will cause the detection wave number area to be limited. Among them, the wave number is represented by the horizontal axis frequency.

In one embodiment, a dual-pulse stimulated Fourier transform coherent anti-Stokes Raman spectroscopy detection system is provided. As shown in FIG2 , the dual-pulse stimulated Fourier transform coherent anti-Stokes Raman spectroscopy detection system includes a light source structure 1, a beam combining structure 2, a replica structure 3 and a detection structure 4; the light source structure 1 is used to generate a first Stokes pulse and a first pump pulse, and adjust the first Stokes pulse to obtain a second Stokes pulse so that the central wavelengths of the Stokes pulse and the pump pulse are separated by a preset interval; the beam combining structure 2 is used to adjust the first pump pulse to obtain a second pump pulse so that the Stokes pulse matches the pump pulse in time domain and focus, and merge the second Stokes pulse and the second pump pulse to obtain a first merged pulse; the replica structure 3 is used to replicate the first merged pulse to obtain a second merged pulse and a third merged pulse with relative delay; the detection structure 4 is used to excite the target detection sample with the second merged pulse and the third merged pulse to determine the detection result of the target detection sample.

In the embodiment of the present application, the dual-pulse stimulated Fourier transform coherent anti-Stokes Raman spectroscopy detection system includes a light source structure 1, a beam combining structure 2, a replication structure 3 and a detection structure 4.

The light source structure 1 first generates a first Stokes pulse and a first pump pulse, and then adjusts the first Stokes pulse to obtain a second Stokes pulse so that the central wavelengths of the Stokes pulse and the pump pulse are separated by a preset interval, thereby adjusting the spectral coverage range according to the preset interval.

The beam combining structure 2 first adjusts the first pump pulse emitted by the light source structure 1 to obtain the second pump pulse, so that the Stokes pulse matches the pump pulse in time domain and focus. Then the beam combining structure 2 combines the second pump pulse and the second Stokes pulse emitted by the light source structure 1 to finally obtain the first combined pulse.

The replica structure 3 performs replica processing and delay processing on the first combined pulse emitted by the beam combining structure 2 to obtain a second combined pulse and a third combined pulse with relative delay.

The detection structure 4 uses the second combined pulse and the third combined pulse with relative delay in the replica structure 3 to excite the target detection sample, collect the excited anti-Stokes scattering, filter and detect the anti-Stokes scattering, etc., to form a coherent anti-Stokes Raman scattering signal, and finally determine the sample information of the target detection sample according to the anti-Stokes Raman scattering signal. The sample information includes structure, properties, etc. The embodiment of the present application does not limit the sample information.

In the above embodiment, the dual-pulse stimulated Fourier transform coherent anti-Stokes Raman spectroscopy detection system includes a light source structure, a beam combining structure, a replica structure and a detection structure; the light source structure generates a first Stokes pulse and a first pump pulse, and adjusts the first Stokes pulse to obtain a second Stokes pulse so that the central wavelengths of the Stokes pulse and the pump pulse are separated by a preset interval; the beam combining structure adjusts the first pump pulse to obtain a second pump pulse so that the Stokes pulse and the pump pulse match in time domain and focus, and merges the second Stokes pulse and the second pump pulse to obtain a first merged pulse; the replica structure replicates the first merged pulse to obtain a second merged pulse and a third merged pulse with relative delay; the detection structure uses the second merged pulse and the third merged pulse to excite the target detection sample to determine the detection result of the target detection sample. The embodiment of the present application excites, collects and detects the target detection sample through a dual-pulse stimulated Fourier transform coherent anti-Stokes Raman spectroscopy detection system to obtain Raman spectral information of molecular oscillations. Since the light source structure can generate dual pulses and the spacing between the central wavelengths of the dual pulses can be adjusted, the coverage of the spectrum can be expanded to areas with higher wave numbers instead of being limited to areas with lower wave numbers. The detectable wave number range is flexible and controllable, thereby realizing the excitation and detection of molecular oscillations in any wave number area.

In one embodiment, as shown in FIG3 , the light source structure 1 includes a pulse generating device 11, a spectrometer 12 and a wavelength adjusting device 13; the pulse generating device 11 is used to generate an original pulse; the spectrometer 12 is used to perform spectroscopic processing on the original pulse to obtain a first Stokes pulse and a first pump pulse; the wavelength adjusting device 13 is used to perform wavelength adjustment on the first Stokes pulse to obtain a second Stokes pulse.

In the embodiment of the present application, the light source structure 1 includes a pulse generating device 11, a spectrometer 12 and a wavelength adjusting device 13. The pulse generating device 11 generates an original pulse. The spectrometer 12 performs spectroscopic processing on the original pulse generated by the pulse generating device 11 to obtain a first Stokes pulse and a first pump pulse.

The wavelength adjustment device 13 contains nonlinear optical fiber. By utilizing the balance between the nonlinearity and dispersion effect of the nonlinear optical fiber, the wavelength of the first Stokes pulse emitted by the optical splitter 12 can be adjusted to change the wavelength of the first Stokes pulse and obtain a second Stokes pulse.

The original pulse is a transformation-limited broadband femtosecond pulse, and the second Stokes pulse is a transformation-limited soliton femtosecond pulse with a longer wavelength.

In the above embodiment, the light source structure includes a pulse generating device, a spectrometer and a wavelength adjusting device; the pulse generating device generates an original pulse; the spectrometer is used to perform spectroscopic processing on the original pulse to obtain a first Stokes pulse and a first pump pulse; the wavelength adjusting device adjusts the wavelength of the first Stokes pulse to obtain a second Stokes pulse. The embodiment of the present application can obtain a set of double pulses through the spectrometer, which establishes the premise for the double-pulse stimulated Fourier transform coherent anti-Stokes Raman spectroscopy detection system. The wavelength adjusting device can change the wavelength of the first Stokes pulse. Since the wave number of the first pump pulse remains unchanged, the wave number difference between the first Stokes pulse and the first pump pulse can be adjusted, thereby adjusting the coverage range of the spectrum in the spectrum diagram.

In one embodiment, as shown in FIG. 4 , the optical splitter 12 includes a half-wave plate 121 and a polarization beam splitter 122; the half-wave plate 121 is used to adjust the polarization direction of the original pulse to obtain an adjusted pulse; the polarization beam splitter 122 is used to perform beam splitting on the adjusted pulse to obtain a first Stokes pulse and a first pump pulse.

In the embodiment of the present application, the optical splitter 12 includes a half-wave plate 121 and a polarization beam splitter 122. The half-wave plate 121 adjusts the polarization direction of the original pulse to obtain an adjusted pulse with a different polarization direction. The polarization beam splitter 122 performs beam splitting processing on the adjusted pulse adjusted by the half-wave plate 121 to obtain a first Stokes pulse and a first pump pulse. The first Stokes pulse enters the wavelength adjustment device 13, and the first pump pulse enters the beam combining structure 2.

For example, when the angle between the polarization direction of the original pulse at the time of incidence and the main axis of the half-wave plate 121 is θ, the polarization direction of the adjustment pulse transmitted from the half-wave plate 121 is rotated by 2θ from the original direction, and an adjustment pulse with two polarization directions is obtained. Then, the polarization beam splitter 122 performs beam splitting processing on the adjustment pulse with two polarization directions after adjustment by the half-wave plate 121 to obtain the first Stokes pulse and the first pump pulse.

In the above embodiment, the half-wave plate is used to adjust the polarization direction of the original pulse, which can change the pulse power passing through the polarization beam splitter, and then change the wavelength adjustment of the wavelength adjustment device, so that the detection wave number area formed by the pump pulse and the Stokes pulse can cover any area of interest.

In one embodiment, as shown in FIG5 , the beam combining structure 2 includes a time domain adjustment component 21, a focus adjustment component 22 and a beam combiner 23; the time domain adjustment component 21 is used to perform time domain adjustment on the first pump pulse to obtain a pump pulse after time domain adjustment; the focus adjustment component 22 is used to adjust the focus position of the pump pulse after time domain adjustment to obtain a second pump pulse; the beam combiner 23 is used to combine the second Stokes pulse and the second pump pulse to obtain a first combined pulse.

In the embodiment of the present application, the beam combining structure 2 includes a time domain adjustment component 21 , a focus adjustment component 22 and a beam combiner 23 .

The time domain adjustment component 21 adjusts the optical path of the first pump pulse on the time domain adjustment component 21, thereby changing the first pump pulse to obtain a pump pulse after time domain adjustment, so that the Stokes pulse and the pump pulse overlap in the time domain.

The focus adjustment component 22 adjusts the focus position of the pump pulse after time domain adjustment, so that the pump pulse adjusted by the focus adjustment component 22 is close to the parallel light state, and a second pump pulse is obtained, so that the Stokes pulse and the pump pulse overlap in the focus space.

The beam combiner 23 combines the second Stokes pulse and the second pump pulse to obtain a first combined pulse.

In the above embodiment, the first pump pulse can be adjusted by the time domain adjustment component and the focus adjustment component to obtain the second pump pulse, so that the Stokes pulse and the pump pulse overlap in the time domain, which can ensure that the phase difference between the Stokes pulse and the pump pulse is constant, which is conducive to controlling the variable of the time domain position of the Stokes pulse and the pump pulse, and is ready for the subsequent beam combination. In addition, the Stokes pulse and the pump pulse can also be overlapped in the focal space, which can ensure that the focus of the Stokes pulse and the pump pulse and the focus of the first objective lens observing the target detection sample are at the same point. Since the maximum light intensity of the Stokes pulse and the pump pulse should be focused on the focus when exciting the target detection sample, the accuracy of the Stokes pulse and the pump pulse when exciting the target detection sample can also be ensured.

In one embodiment, as shown in Figure 6, the time domain adjustment component 21 includes a first reflector 211, a second reflector 212, a third reflector 214 and an angle mirror 213; the first reflector 211 is used to reflect the first pump pulse to the second reflector 212; the second reflector 212 is used to reflect the pump pulse reflected by the first reflector 211 to the angle mirror 213; the angle mirror 213 is used to reflect the pump pulse reflected by the second reflector 212 to the third reflector 214; the third reflector 214 is used to reflect the pump pulse reflected by the angle mirror 213 to the focus adjustment component 22.

In the embodiment of the present application, the time domain adjustment component 21 includes a first reflector 211, a second reflector 212, a third reflector 214 and an angle mirror 213. The first reflector 211 reflects the first pump pulse obtained through the polarization beam splitter to the second reflector 212; the second reflector 212 reflects the pump pulse reflected by the first reflector 211 to the angle mirror 213. By adjusting the up and down position of the angle mirror 213, the optical path of the pump pulse reflected by the first reflector 211 in the angle mirror 213 is changed. The angle mirror 213 reflects the pump pulse after the optical path is changed to the third reflector 214. The third reflector 214 reflects the pump pulse reflected by the angle mirror 213 to the focus adjustment component 22.

In the above embodiment, the optical path of the pump pulse after reflection by the first reflector in the angle mirror can be changed by changing the upper and lower positions of the angle mirror; the optical path can be adjusted by adjusting the position of the angle mirror, which is beneficial to ensure that the Stokes pulse and the pump pulse coincide in the time domain, and can ensure that the phase difference between the Stokes pulse and the pump pulse is constant, which is beneficial to control the variable of the time domain position of the Stokes pulse and the pump pulse, and prepare for the subsequent beam combining.

In one embodiment, as shown in FIG. 7 , the focus adjustment assembly 22 includes a first lens 221 , a second lens 222 and a fourth reflector 223 ; the optical axes of the first lens 221 and the second lens 222 are located in the same straight line; the first lens 221 and the second lens 222 are used to adjust the focal position of the pump pulse to obtain a second pump pulse; the fourth reflector 223 is used to reflect the second pump pulse to the combiner 23 .

In the embodiment of the present application, the focus adjustment component 22 includes a first lens 221, a second lens 222 and a fourth reflector 223. The optical axes of the first lens 221 and the second lens 222 are located in the same straight line. The distance between the first lens 221 and the second lens 222 is adjusted to change the spot state of the pump pulse passing through the two lenses. When the distance between the two lenses is close to the sum of the focal lengths of the two lenses, the focus of the Stokes pulse and the pump pulse through the first objective lens 41 is focused at the same point, and then the second pump pulse is obtained. The fourth reflector 223 reflects the second pump pulse to the combiner 23.

For example, the pump pulse in the second combined pulse is pre-adjusted by the focus adjustment component 22 so that the Stokes pulse and the pump pulse are focused at the same point through the first objective lens 41. The pump pulse and Stokes pulse required for exciting the target detection sample can be provided by the second combined pulse or the third combined pulse. After exciting the sample, anti-Stokes Raman scattering can be obtained. The frequency domain principle diagram of the coherent anti-Stokes scattering signal generated when the double pulse interacts with the sample is shown in Figure 8. Among them, the spectral coverage area of the coherent anti-Stokes Raman scattering formed by the pump pulse and the Stokes pulse can be approximated as the cross-correlation of the pump pulse and the Stokes pulse spectrum. Therefore, by adjusting the center frequency difference of the two pulses, the flexible regulation of the detection spectrum coverage area can be achieved. As long as the frequency difference of the double pulses is large enough, the excitation detection can also be achieved for the molecular oscillation _QR of the high frequency Ω ₀ , wherein the wave number is represented by the horizontal axis frequency, that is, the frequency difference is the wave number difference. The time domain principle diagram is shown in Figure 9, and the combined action of the pump pulse and the Stokes pulse excites the relaxation oscillation q of the molecule.

In the above embodiment, by adjusting the distance between the two lenses, the pump pulse adjusted by the focus adjustment component can be close to the parallel light state, ensuring that the Stokes pulse and the pump pulse are focused at the same point through the first objective lens, so that the Stokes pulse and the pump pulse overlap in the focal space. Since the maximum light intensity of the Stokes pulse and the pump pulse should be excited at the focus when the sample is excited, the accuracy of the Stokes pulse and the pump pulse when exciting the target detection sample can also be ensured. Since the excitation requirement of the impact stimulated Fourier transform coherent anti-Stokes Raman spectroscopy detection method is that the pulse width is less than half of the molecular vibration period to obtain the excitation efficiency, the use of a dual-pulse stimulated Fourier transform coherent anti-Stokes Raman spectroscopy detection system can make the dual pulse combination excite molecular oscillations, so the pulse width of the pump and Stokes does not need to be less than half of the oscillation period, which can greatly reduce the requirements for the light source.

In one embodiment, as shown in Figure 10, the replication structure 3 includes a beam splitter 31, a first delay component 32 and a second delay component 33; the beam splitter 31 is used to replicate the first merged pulse to obtain a first replicated pulse and a second replicated pulse; the first delay component 32 is used to reflect the first replicated pulse to obtain a second merged pulse; the second delay component 33 is used to delay the second replicated pulse to obtain a third merged pulse; the beam splitter 31 is also used to merge the second merged pulse and the third merged pulse, and emit the merged second merged pulse and the third merged pulse to the detection structure 4.

In the embodiment of the present application, the replication structure 3 includes a beam splitter 31, a first delay component 32 and a second delay component 33. The beam splitter 31 divides the double pulses with equal power that overlap in time and space into two groups, namely the first replication pulse and the second replication pulse. One group enters the first delay component 32, and the first delay component 32 performs reflection processing on the first replication pulse to obtain the second combined pulse; the other group enters the second delay component 33, and the second delay component 33 performs delay processing on the second replication pulse to obtain the third combined pulse.

The beam splitter 31 also combines the second combined pulse and the third combined pulse, and emits the combined second combined pulse and the third combined pulse to the detection structure 4 .

In the above embodiment, the first delay component and the second delay component can perform delay processing on the two groups of double pulses to form two groups of double pulses with constantly changing relative delays, thereby providing pulse conditions for the double-pulse stimulated Fourier transform coherent anti-Stokes Raman scattering spectroscopy detection system, which is conducive to intuitively detecting the oscillation information of the reaction molecules.

In one embodiment, as shown in Figure 11, the second delay component 33 includes a fifth reflector 331, a curved mirror 332 and a resonant scanning mirror 333; the second replica pulse is reflected by the fifth reflector 331, the curved mirror 332, the resonant scanning mirror 333, the curved mirror 332 and the fifth reflector 331 in sequence, and returns to the beam splitter 31.

In the embodiment of the present application, the second delay component 33 includes a fifth reflector 331, a curved mirror 332 and a resonant scanning mirror 333. The second replica pulse is reflected by the fifth reflector 331, the curved mirror 332, the resonant scanning mirror 333, the curved mirror 332 and the fifth reflector 331 in sequence and returns to the beam splitter 31.

For example, one path passes through the reference arm formed by the first delay component 32, and the other path passes through the scanning arm formed by the fifth reflector 331, the curved mirror 332, and the resonant scanning mirror 333. After passing through the two arms, the pulse is recombined by the beam splitter 31 to form two groups of double pulses with a common optical path. Among them, through the scanning of the resonant scanning mirror 333, the optical path of the scanning arm is constantly changing, so that the relative delay of the two groups of double pulses is also constantly changing.

The schematic diagram of the dual-pulse stimulated Fourier transform coherent anti-Stokes Raman spectroscopy detection system is shown in Figure 12. Each set of dual pulses that overlap in time and space each excites a relaxation oscillation molecular response, which is recorded as q ₁ and q ₂ respectively. When the relative delay of the two sets of dual pulses is greater than the pulse width and less than the relaxation time of the molecular response, the total molecular response is the linear superposition of the two, q = q ₁ + q _2. Among them, the amplitude of the anti-Stokes scattering field is proportional to the product of the molecular response and the pump pulse amplitude. Therefore, at this time, the anti-Stokes scattering consists of two parts, one part is generated by the first pump pulse (pump pulse 1) and q ₁ , and the other part is generated by the second pump pulse (pump pulse 2) and the total molecular response q.

As the two groups of double pulses are scanned with relative time delay, the intensity of the former remains unchanged, and its contribution to the final signal is a DC quantity, which does not provide information on molecular oscillation; while the latter reflects the relaxation oscillation of the molecule: the total molecular response q is the coherent superposition of _q1 and _q2 , and as the relative time delay changes, it continuously forms changes in in-phase constructive interference and anti-phase destructive interference, while the intensity of pump pulse 2 remains unchanged. Therefore, the change in the anti-Stokes scattering intensity formed by them with the relative time delay reflects the line shape of the molecular relaxation oscillation. The anti-Stokes intensity scanned with relative time delay obtained in this way is the interference pattern in the dual-pulse stimulated Fourier transform coherent anti-Stokes Raman spectroscopy detection system. Finally, the obtained interference pattern signal is Fourier transformed to obtain a broadband Raman spectrum, thereby obtaining molecular spectral line information.

In the above embodiment, the second delay component can be used as a scanning arm. Through the scanning of the resonant scanning mirror, the optical path of the scanning arm is constantly changing, so that the relative delay of the two groups of double pulses is also constantly changing. Therefore, it can provide the hardware conditions for the interference of the two groups of double pulses with relative delay, which is conducive to the intuitive analysis of molecular oscillations.

In one embodiment, as shown in FIG13 , the detection structure 4 includes a first objective lens 41, a second objective lens 42 and a detection assembly 43; the first objective lens 41 is used to excite the target detection sample using the second combined pulse and the third combined pulse to obtain a first excitation light; the second objective lens 42 is used to collect the first excitation light to obtain a second excitation light; the detection assembly 43 is used to determine the detection result of the target detection sample according to the second excitation light.

In the embodiment of the present application, the detection structure 4 includes a first objective lens 41, a second objective lens 42 and a detection component 43. The first objective lens 41 uses the second combined pulse and the third combined pulse to focus on the target detection sample, and can excite the target detection sample to obtain the first excitation light. Then, the second objective lens 42 collects the first excitation light to obtain the second excitation light; the detection component 43 determines the detection result of the target detection sample according to the second excitation light. Among them, the first excitation light is anti-Stokes scattering.

In the above embodiment, the second combined pulse and the third combined pulse in the first objective lens excite the target detection sample to obtain the first excitation light. Since the maximum illumination intensity of the Stokes pulse and the pump pulse should be excited at the focus when the target detection sample is excited, the accuracy of the Stokes pulse and the pump pulse when the target detection sample is excited can also be ensured. Since the excitation requirement of the impact stimulated Fourier transform coherent anti-Stokes Raman spectroscopy detection method is that the pulse width is less than half of the molecular vibration period to obtain the excitation efficiency, the use of a dual-pulse stimulated Fourier transform coherent anti-Stokes Raman spectroscopy detection system can make the dual pulse combination excite molecular oscillations, so the pulse width of the pump and Stokes does not need to be less than half of the oscillation period, which can greatly reduce the requirements for the light source.

In one embodiment, as shown in FIG. 14 , the detection component 43 includes a filter 431 and a detector 432 ; the filter 431 is used to filter the second excitation light to obtain a third excitation light; the detector 432 is used to perform detection processing based on the third excitation light to determine the detection result of the target detection sample.

In the embodiment of the present application, the detection component 43 includes a filter 431 and a detector 432. The filter 431 filters out the long-wavelength processing of the second excitation light to obtain the third excitation light; the detector 432 performs detection processing based on the third excitation light to form a coherent anti-Stokes Raman scattering signal, and analyzes the material structure composition information of the target detection sample based on the coherent anti-Stokes Raman scattering signal. Among them, the third excitation light is the short-wave anti-Stokes scattering after the filter 431 filters out the long-wavelength processing.

In the above embodiment, a filter can be used to filter out Stokes pulses and pump pulses with longer wavelengths to obtain short-wavelength anti-Stokes scattering, and then a detector is used to detect the short-wavelength anti-Stokes scattering to obtain a coherent anti-Stokes Raman scattering signal, which is beneficial for reflecting molecular oscillations according to the coherent anti-Stokes Raman scattering signal and obtaining the material structure composition information of the target detection sample.

The technical features of the above embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the present application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the attached claims.

Claims (10)

1. A dual-pulse stimulated Fourier transform coherent anti-Stokes Raman spectroscopy detection system, characterized in that the dual-pulse stimulated Fourier transform coherent anti-Stokes Raman spectroscopy detection system comprises a light source structure, a beam combining structure, a replication structure and a detection structure; The light source structure is used to generate a first Stokes pulse and a first pump pulse, and adjust the first Stokes pulse to obtain a second Stokes pulse so that the central wavelengths of the Stokes pulse and the pump pulse are separated by a preset distance; The beam combining structure is used to adjust the first pump pulse to obtain a second pump pulse, so that the Stokes pulse matches the pump pulse in both time domain and focus, and combine the second Stokes pulse and the second pump pulse to obtain a first combined pulse; The replication structure is used to replicate the first combined pulse to obtain a second combined pulse and a third combined pulse with relative delay; The detection structure is used to excite the target detection sample using the second combined pulse and the third combined pulse to determine the detection result of the target detection sample. 2. The dual-pulse stimulated Fourier transform coherent anti-Stokes Raman spectroscopy detection system according to claim 1, characterized in that the light source structure includes a pulse generating device, a spectroscopic device and a wavelength adjusting device; The pulse generating device is used to generate an original pulse; The optical splitter is used to perform optical splitting processing on the original pulse to obtain the first Stokes pulse and the first pump pulse; The wavelength adjustment device is used to adjust the wavelength of the first Stokes pulse to obtain the second Stokes pulse. 3. The double-pulse stimulated Fourier transform coherent anti-Stokes Raman spectroscopy detection system according to claim 2, characterized in that the optical splitter comprises a half-wave plate and a polarization beam splitter; The half-wave plate is used to adjust the polarization direction of the original pulse to obtain an adjusted pulse; The polarization beam splitter is used to perform beam splitting processing on the adjustment pulse to obtain the first Stokes pulse and the first pump pulse. 4. The double-pulse stimulated Fourier transform coherent anti-Stokes Raman spectroscopy detection system according to claim 1, characterized in that the beam combining structure includes a time domain adjustment component, a focus adjustment component and a beam combiner; The time domain adjustment component is used to perform time domain adjustment on the first pump pulse to obtain a pump pulse after time domain adjustment; The focus adjustment component is used to adjust the focus position of the pump pulse after the time domain adjustment to obtain the second pump pulse; The beam combiner is used to combine the second Stokes pulse and the second pump pulse to obtain the first combined pulse. 5. The double-pulse stimulated Fourier transform coherent anti-Stokes Raman spectroscopy detection system according to claim 4, characterized in that the time domain adjustment component comprises a first reflector, a second reflector, a third reflector and a corner mirror; The first reflector is used to reflect the first pump pulse to the second reflector; The second reflector is used to reflect the pump pulse reflected by the first reflector to the corner mirror; The corner mirror is used to reflect the pump pulse reflected by the second reflector to the third reflector; The third reflector is used to reflect the pump pulse reflected by the corner mirror to the focus adjustment component. 6. The double-pulse stimulated Fourier transform coherent anti-Stokes Raman spectroscopy detection system according to claim 4, characterized in that the focus adjustment component comprises a first lens, a second lens and a fourth reflector; the optical axes of the first lens and the second lens are located in the same straight line; The first lens and the second lens are used to adjust the focal position of the pump pulse to obtain the second pump pulse; The fourth reflector is used to reflect the second pump pulse to the beam combiner. 7. The double-pulse stimulated Fourier transform coherent anti-Stokes Raman spectroscopy detection system according to claim 1, characterized in that the replica structure comprises a beam splitter, a first delay component and a second delay component; The beam splitter is used to perform a replication process on the first combined pulse to obtain a first replicated pulse and a second replicated pulse; The first delay component is used to perform reflection processing on the first replica pulse to obtain the second combined pulse; The second delay component is used to perform delay processing on the second replica pulse to obtain the third combined pulse; The beam splitter is further used to combine the second combined pulse and the third combined pulse, and emit the combined second combined pulse and third combined pulse to the detection structure. 8. The double-pulse stimulated Fourier transform coherent anti-Stokes Raman spectroscopy detection system according to claim 7, characterized in that the second delay component comprises a fifth reflector, a curved mirror and a resonant scanning mirror; The second replica pulse is reflected by the fifth reflecting mirror, the curved mirror, the resonant scanning mirror, the curved mirror and the fifth reflecting mirror in sequence and returns to the beam splitter. 9. The double-pulse stimulated Fourier transform coherent anti-Stokes Raman spectroscopy detection system according to claim 1, characterized in that the detection structure comprises a first objective lens, a second objective lens and a detection assembly; The first objective lens is used to excite the target detection sample using the second combined pulse and the third combined pulse to obtain a first excitation light; The second objective lens is used to collect the first excitation light to obtain a second excitation light; The detection component is used to determine the detection result of the target detection sample according to the second excitation light. 10. The double-pulse stimulated Fourier transform coherent anti-Stokes Raman spectroscopy detection system according to claim 9, characterized in that the detection component comprises a filter and a detector; The filter is used to filter the second excitation light to obtain the third excitation light; The detector is used to perform detection processing according to the third excitation light to determine the detection result of the target detection sample.