A coherent anti-Stokes Raman scattering imaging method and apparatus

Abstract

This invention relates to the field of optical detection technology, specifically providing a coherent anti-Stokes Raman scattering imaging method and apparatus, comprising: splitting an initial light emitted from a driving light source into a driving light and a Stokes beam; processing the driving light into a signal light based on an optical parametric amplifier; performing pulse broadening processing on the signal light in a first optical path, or performing pulse broadening processing on the Stokes beam in a second optical path; combining the signal light and the Stokes beam into a third optical path, and performing pulse broadening processing on the signal light and the Stokes beam in the third optical path to obtain chirped signal light and Stokes beam; and performing coherent anti-Stokes Raman scattering imaging on a target sample based on the chirped signal light and the Stokes beam. This addresses the problem that related technologies cannot simultaneously achieve high-quality and fast hyperspectral imaging.

Description

Technical Field

[0001] This invention relates to the field of optical detection technology, and in particular to a coherent anti-Stokes Raman scattering imaging method and apparatus. Background Technology

[0002] Coherent anti-Stokes Raman scattering (CARS) imaging utilizes the resonant coupling of two coherent laser beams with the vibrational energy levels of sample molecules to generate a strongly coherent anti-Stokes light signal. Microscopic imaging is achieved by detecting this signal. Because it allows for the analysis of the microscopic composition and structure of biological / material components without the need for fluorescent dyes or probes, it is a key technology bridging traditional Raman spectroscopy and modern microscopic imaging, and has wide applications in biomedicine, materials science, and other fields.

[0003] Because optical parametric oscillators (OPOs) have lower laser noise than optical parametric amplifiers (OPAs), and because OPOs have narrower output linewidths (spectral widths) and better monochromaticity under picosecond pulse conditions, they have been commonly used for coherent anti-Stokes Raman scattering imaging since the early stages of related technologies. However, the single-pulse energy output of an OPO is limited. To generate a coherent anti-Stokes Raman scattering signal, a pulse width of hundreds of femtoseconds to several picoseconds (1 picosecond = 1000 femtoseconds) is required to obtain sufficiently high peak power. However, this pulse width significantly affects spectral resolution, making it impossible to distinguish some small peaks in the coherent anti-Stokes Raman scattering spectrum due to aliasing. Furthermore, the short pulse width of hundreds of femtoseconds to several picoseconds results in relatively high phototoxicity, which can easily damage biological samples and affect the quality of hyperspectral imaging. In addition, the speed of hyperspectral imaging using OPOs is relatively slow due to the need for wavelength switching.

[0004] There is currently no effective solution to the problem that related technologies cannot simultaneously achieve both hyperspectral imaging quality and hyperspectral imaging speed. Summary of the Invention

[0005] The present invention provides a coherent anti-Stokes Raman scattering imaging method and apparatus, which at least solves the problem that related technologies cannot simultaneously achieve both hyperspectral imaging quality and hyperspectral imaging speed.

[0006] This invention provides a coherent anti-Stokes Raman scattering imaging method, which splits the initial light emitted from a driving light source into a driving light and a Stokes beam; processes the driving light into a signal light based on an optical parametric amplifier; performs pulse broadening processing on the signal light in a first optical path, or on the Stokes beam in a second optical path; combines the signal light and the Stokes beam into a third optical path, and performs pulse broadening processing on the signal light and the Stokes beam in the third optical path to obtain a chirped signal light and a Stokes beam; and performs coherent anti-Stokes Raman scattering imaging on a target sample based on the chirped signal light and the Stokes beam.

[0007] Preferably, pulse broadening processing is performed on the signal light in the first optical path based on multiplexing dispersive elements, or pulse broadening processing is performed on the Stokes light in the second optical path; and pulse broadening processing is performed on both the signal light and the Stokes light in the third optical path based on multiplexing dispersive elements.

[0008] Preferably, before combining the signal light and the Stokes light into the third optical path, the method further includes: adjusting the optical path of the signal light in the first optical path, and / or adjusting the optical path of the Stokes light in the second optical path until the optical path of the signal light and the optical path of the Stokes light match.

[0009] Preferably, before combining the signal light and the Stokes light into the third optical path, the method further includes: performing intensity modulation of the signal light with a duty cycle lower than a preset threshold on the first optical path, and / or performing intensity modulation of the Stokes light with a duty cycle lower than a preset threshold on the second optical path.

[0010] This invention provides a coherent anti-Stokes Raman scattering imaging device, comprising: a driving light source for emitting initial light; a beam splitter disposed in the optical path of the initial light for splitting the initial light into driving light and Stokes light; an optical parametric amplifier disposed in the optical path of the driving light for processing the driving light into signal light; a first dispersion component disposed in the first optical path of the signal light for pulse broadening processing of the signal light, or disposed in the second optical path of the Stokes light for pulse broadening processing of the Stokes light; a beam combiner disposed at the ends of the first and second optical paths for combining the signal light and the Stokes light into a third optical path; a second dispersion component disposed in the third optical path for pulse broadening processing of the signal light and the Stokes light to obtain chirped signal light and Stokes light; and an imaging component disposed along the third optical path after the second dispersion component for performing coherent anti-Stokes Raman scattering imaging of a target sample based on the chirped signal light and the Stokes light.

[0011] Preferably, the first dispersion component includes a first reflective element and a first dispersion element. The first reflective element is disposed at both ends of the first dispersion element. The first reflective element is configured to allow the signal light or Stokes light to repeatedly pass through the first dispersion element. The first dispersion element is configured to perform pulse broadening processing on the signal light or Stokes light. The second dispersion component includes a second reflective element and a second dispersion element. The second reflective element is disposed at both ends of the second dispersion element. The second reflective element is configured to allow the signal light and Stokes light to repeatedly pass through the second dispersion element. The second dispersion element is configured to perform pulse broadening processing on the signal light and Stokes light.

[0012] Preferably, the first reflecting element and the second reflecting element each include at least one of the following: a non-D-shaped mirror, a D-shaped mirror, a hollow roof reflecting prism, a polarizing beam splitter cube mirror, and a quarter-wave plate; the first dispersive element and the second dispersive element each include at least one of the following: a dispersive material, a grating, a prism, and a chirped mirror.

[0013] Preferably, it further includes a first delay line assembly and / or a second delay line assembly; the first delay line assembly is disposed in the first optical path for adjusting the optical path of the signal light; the second delay line assembly is disposed in the second optical path for adjusting the optical path of the Stokes light.

[0014] Preferably, the above-mentioned device further includes a first beam expander and / or a second beam expander; the first beam expander is disposed in the first optical path and is used to adjust the size of the signal light; the second beam expander is disposed in the second optical path and is used to adjust the size of the Stokes light.

[0015] Preferably, the above-mentioned device further includes a first optical modulator and / or a second optical modulator; the first optical modulator is disposed in the first optical path and is used to perform intensity modulation of the signal light with a duty cycle lower than a preset threshold; the second optical modulator is disposed in the second optical path and is used to perform intensity modulation of the Stokes light with a duty cycle lower than a preset threshold.

[0016] This invention provides a coherent anti-Stokes Raman scattering imaging method and apparatus. The method involves splitting the initial light emitted from a driving light source into a driving beam and a Stokes beam. The driving beam is then processed into a signal beam using an optical parametric amplifier. Pulse broadening is performed on the signal beam in a first optical path, or on the Stokes beam in a second optical path. The signal beam and the Stokes beam are then combined into a third optical path, where pulse broadening is performed again to obtain chirped signal and Stokes beams. Based on the chirped signal and Stokes beams, coherent anti-Stokes Raman scattering imaging is performed on the target sample. This design, which involves first broadening one path and then combining the beams, allows for flexible control of the group delay dispersion of the signal and Stokes beams. Combined with spectral focusing techniques, the wavenumber and delay line shift are correlated, thereby achieving hyperspectral imaging within a certain range within a short time. By broadening the femtosecond pulses of signal light and Stokes light into linear chirped pulses of tens of picoseconds, peak power can be reduced, thereby eliminating phototoxicity and achieving centimeter-scale optical microscopy (CMS). -1 This achieves ultra-high spectral resolution, addressing the challenge of balancing hyperspectral imaging quality and speed in existing technologies. Attached Figure Description

[0017] To more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are merely some embodiments of the present invention, and those skilled in the art can obtain other embodiments based on these drawings without creative effort.

[0018] Figure 1 This is a flowchart illustrating the steps of a coherent anti-Stokes Raman scattering imaging method in an embodiment of the present invention.

[0019] Figure 2 This is one of the structural schematic diagrams of a coherent anti-Stokes Raman scattering imaging device in an embodiment of the present invention.

[0020] Figure 3 This is one of the structural schematic diagrams of the first dispersion component in the embodiments of the present invention.

[0021] Figure 4 This is the second schematic diagram of the structure of the first dispersive component in the embodiment of the present invention.

[0022] Figure 5 This is the third schematic diagram of the structure of the first dispersive component in the embodiment of the present invention.

[0023] Figure 6 This is the fourth schematic diagram of the structure of the first dispersive component in the embodiment of the present invention.

[0024] Figure 7 This is a schematic diagram of the imaging process for adjusting the optical path of Stokes light in an embodiment of the present invention.

[0025] Figure 8 This is the second schematic diagram of the structure of a coherent anti-Stokes Raman scattering imaging device in an embodiment of the present invention.

[0026] The above figures include the following reference numerals:

[0027] 1. Driving light source; 2. Beam splitter; 3. Optical parametric amplifier; 4. First dispersion component; 5. Beam combiner; 6. Second dispersion component; 7. Target sample;

[0028] 8. First delay line assembly; 9. Second delay line assembly;

[0029] 10. First convex lens; 11. First concave lens; 12. Second convex lens; 13. Third convex lens; 14. Second concave lens; 15. Fourth convex lens;

[0030] 16. First optical modulator; 17. Second optical modulator;

[0031] 18. Dichroic mirror; 19. Scanning galvanometer; 20. Objective lens; 21. Condenser lens; 22. First detector; 23. Data acquisition card; 24. Computer; 25. Second detector;

[0032] 26. First reflecting mirror; 27. Second reflecting mirror; 28. Third reflecting mirror; 29. ​​Fourth reflecting mirror;

[0033] 301. First hollow roof ridge reflecting prism; 302. Second hollow roof ridge reflecting prism; 41. Dispersive material;

[0034] 401. First D-shaped reflector; 402. Second D-shaped reflector; 403. First non-D-shaped reflector; 404. Second non-D-shaped reflector;

[0035] 501. First polarizing beam-splitting cubic mirror; 502. Quarter-wave plate; 503. Third non-D-shaped mirror;

[0036] 601. Third hollow roof ridge reflecting prism; 602. Third D-shaped reflecting mirror. Detailed Implementation

[0037] Embodiments of the present invention will now be described in more detail with reference to the accompanying drawings. While some embodiments of the present invention are shown in the drawings, it should be understood that the present invention can be implemented in various forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of the present invention. It should be understood that the drawings and embodiments of the present invention are for illustrative purposes only and are not intended to limit the scope of protection of the present invention.

[0038] Because optical parametric oscillators (OPOs) have lower laser noise than optical parametric amplifiers (OPA), and because OPOs have narrower output linewidths and better monochromaticity under picosecond pulse conditions, they have been commonly used for coherent anti-Stokes Raman scattering (ASR) imaging since its early development. However, the single-pulse energy output of an OPO is limited. To generate a coherent ASR signal, a pulse width of hundreds of femtoseconds to several picoseconds is required to obtain sufficiently high peak power. This pulse width significantly affects spectral resolution, making it impossible to distinguish some small peaks in the coherent ASR spectrum due to aliasing. Furthermore, the short pulse width of hundreds of femtoseconds to several picoseconds results in relatively high phototoxicity, which can easily damage biological samples and affect the quality of hyperspectral imaging. In addition, the speed of hyperspectral imaging using OPOs is relatively slow due to the need for wavelength switching.

[0039] Therefore, please refer to Figure 1 As shown, the present invention provides a coherent anti-Stokes Raman scattering imaging method, including steps S101 to S105.

[0040] Step S101: The initial light emitted by the driving light source is split into driving light and Stokes light.

[0041] Step S102: The driving light is processed into signal light based on the optical parametric amplifier.

[0042] Step S103: Perform pulse broadening processing on the signal light in the first optical path of the signal light, or perform pulse broadening processing on the Stokes light in the second optical path of the Stokes light.

[0043] In step S104, the signal light and the Stokes light are combined into the third optical path. In the third optical path, the signal light and the Stokes light are pulse-stretched to obtain a chirped signal light and a Stokes light.

[0044] Step S105: Based on the chirped rate matched signal light and Stokes light, coherent anti-Stokes Raman scattering imaging is performed on the target sample.

[0045] When splitting the initial light emitted by the driving light source into driving light and Stokes light, the principle that the Stokes light must meet the minimum power requirement for coherent anti-Stokes Raman scattering must be followed. Since coherent anti-Stokes Raman scattering does not have high power requirements, the resulting Stokes light can constitute only a small portion of the initial light emitted by the driving light source, for example, 10%. In other words, the initial light can be split into driving light and Stokes light in a 9:1 ratio. This ratio is merely an example; those skilled in the art can set other ratios based on the actual power requirements of coherent anti-Stokes Raman scattering.

[0046] By using an optical parametric amplifier to process the driving light from the driving light source into signal light, compared to using an independent light source other than the driving light source to activate the optical parametric amplifier to obtain signal light, the signal light and Stokes light can be synchronized better, which is helpful for subsequent coherent anti-Stokes Raman scattering imaging.

[0047] For example, a driving light with a wavelength of 1030 nm is processed into a signal light with a wavelength tunable in the range of 600-1000 nm based on an optical parametric amplifier.

[0048] This embodiment provides the following detailed explanation of the differences between optical parametric oscillators and optical parametric amplifiers.

[0049] Optical parametric oscillators (OPOs) have the advantage of narrow linewidth under picosecond pulse conditions. Because linewidth and pulse width are coupled, under the Fourier limit, a smaller pulse width results in a larger linewidth. Here, linewidth refers to the spectral width; a larger linewidth indicates more color components. Pulse width refers to the temporal width, i.e., the duration of each pulse output.

[0050] However, due to the low single-pulse energy of optical parametric oscillators (OPOs), they cannot be broadened to 2-3 picoseconds or higher; otherwise, the peak power would be too low to excite nonlinear effects. Therefore, OPOs either require tuning to achieve hyperspectral imaging or use spectral focusing, which only yields hyperspectral imaging with lower spectral resolution.

[0051] Although optical parametric amplifiers do not have a significant advantage over optical parametric oscillators in terms of linewidth, they have high single-pulse energy. This allows them to stretch femtosecond pulses to tens of picoseconds while still maintaining a high degree of color density (this is not the Fourier limit).

[0052] Meanwhile, compared to optical parametric oscillators, optical parametric amplifiers have lower device costs and are easier to maintain. Therefore, the method provided in this embodiment, which uses an optical parametric amplifier, can lower the application threshold of coherent anti-Stokes Raman scattering technology and has good economic efficiency and practicality.

[0053] Pulse broadening involves expanding the femtosecond (fs) pulses of both the signal and Stokes beams into picosecond (ps) linearly chirped pulses to obtain chirped signal and Stokes beams with matched chirp rates. This, combined with spectral focusing techniques, allows for the correlation between wavenumber and delay line shift, enabling hyperspectral imaging within a specific range over a short time. Furthermore, by incorporating spectral focusing techniques, the drawbacks of high noise and large output linewidth in optical parametric amplifiers can be overcome.

[0054] Here, wavenumber refers to the frequency difference between the signal light and the Stokes light, and delay line displacement refers to adjusting the optical path length of the signal light or Stokes light through an optical delay line, thereby changing the time difference between the signal light and the Stokes light reaching the focal point of the target sample. Essentially, it adjusts the optical path difference through physical displacement to achieve a precise mapping between time delay and wavenumber. Specific explanations of adjusting the optical path length of the signal light and / or Stokes light will follow in this embodiment.

[0055] Next, the core of pulse broadening is the introduction of controllable group delay dispersion (GDD) to generate linear chirp whose instantaneous frequency changes linearly with time. Considering the different wavelengths of the signal light and Stokes light (the larger the wavelength, the lower the frequency), this embodiment adopts a design of first broadening a single path and then combining the beams for broadening. This design can flexibly control the group delay dispersion of the signal light and Stokes light, achieving chirp rate matching between the signal light and Stokes light.

[0056] Compared to related technologies that require scanning each wavelength and imaging each wavenumber for hyperspectral coherent anti-Stokes Raman scattering, which is time-consuming (usually on the order of seconds or even minutes), the method provided in this embodiment achieves significantly faster results. Figure 7 Taking the adjustment of the optical path of the Stokes light in the second optical path as an example, the use of a delay line component to adjust the optical path of the Stokes light can establish a correspondence between the wavenumber and the delay line displacement. By simply adjusting the delay line and collecting data with the detector, coherent anti-Stokes Raman scattering signals in the target wavenumber range can be quickly captured, compressing the imaging time to the millisecond or even microsecond level, and realizing hyperspectral imaging in a short time.

[0057] Meanwhile, compared to the fact that the optical power output of an optical parametric oscillator (OPO) typically only reaches the hundreds of milliwatts level, this embodiment uses an OPO to obtain signal light output at the level of several watts at low cost, providing more options and possibilities for coherent anti-Stokes Raman scattering imaging. Regarding the potential problem of phototoxicity caused by excessively high peak power when using an OPO, this embodiment reduces the peak power by broadening the femtosecond pulses of the signal light and Stokes light into linear chirped pulses of tens of picoseconds, thereby eliminating phototoxicity and achieving centimeter-scale imaging. -1 Ultra-high spectral resolution at the level of [missing information].

[0058] Therefore, the method provided in this embodiment can solve the problem that related technologies cannot simultaneously achieve both hyperspectral imaging quality and hyperspectral imaging speed.

[0059] Preferably, pulse broadening processing is performed on the signal light in the first optical path based on multiplexing dispersive elements, or pulse broadening processing is performed on the Stokes light in the second optical path; and pulse broadening processing is performed on both the signal light and the Stokes light in the third optical path based on multiplexing dispersive elements.

[0060] Dispersive elements can be, but are not limited to, dispersive materials, gratings, chirped mirrors, prisms, fiber Bragg gratings (FBGs), and optical fibers. Dispersive materials can be, but are not limited to, optical glass and crystals.

[0061] Multiplexing a dispersive element refers to passing the signal light and / or Stokes light through the same dispersive element multiple times. Single-path broadening (pulse broadening of the signal light in the first optical path, or pulse broadening of the Stokes light in the second optical path) and beam combining broadening (pulse broadening of the signal light and Stokes light in the third optical path) can use the same or different dispersive elements.

[0062] By using multiplexed dispersive elements, such as multiplexing dispersive materials, mega-scale (fs) can be achieved using dispersive materials spanning tens of centimeters (cm). 2 The group delay dispersion at this level broadens the femtosecond pulse into a linear chirped pulse of tens of picoseconds. It should be noted that the aforementioned tens of centimeters of dispersive material, after multiplexing, is equivalent to several meters of dispersive material. Specifically, the actual length of the dispersive material used is L. After multiplexing this dispersive material N times, the signal light and / or Stokes light actually pass through a dispersive material of length L×N, where L can be tens of centimeters and L×N can be several meters. The present invention provides several preferred methods for multiplexing dispersive materials.

[0063] Preferably, before combining the signal light and the Stokes light into the third optical path in step S104, the method further includes: adjusting the optical path of the signal light in the first optical path, and / or adjusting the optical path of the Stokes light in the second optical path until the optical path of the signal light and the optical path of the Stokes light match.

[0064] It should be noted that the optical path adjustment in the above preferred method refers to fine-tuning or small-scale adjustment of the signal light and / or Stokes light based on the coarse adjustment of the optical path when performing coherent anti-Stokes Raman scattering imaging with related technologies, so as to ensure that the optical path of the signal light and the optical path of the Stokes light are matched.

[0065] Fine-tuning of the optical path can be achieved by, but is not limited to, using at least one of the following: a delay line assembly, a variable thickness optical plate, or a fiber stretcher. The embodiments of this invention will subsequently be described with the delay line assembly as a preferred option.

[0066] The optical path matching between the signal light and the Stokes light means that the sum of the initial optical path difference between the signal light and the Stokes light, and the optical path difference between the signal light and the Stokes light within the imaging system, is zero. The aforementioned imaging system refers to a coherent anti-Stokes Raman scattering imaging system configured based on the method provided in this embodiment, and the imaging system includes the aforementioned first optical path, second optical path, and third optical path.

[0067] Preferably, before combining the signal light and the Stokes light into the third optical path in step S104, the method further includes: performing intensity modulation of the signal light with a duty cycle lower than a preset threshold on the first optical path, and / or performing intensity modulation of the Stokes light with a duty cycle lower than a preset threshold on the second optical path.

[0068] Intensity modulation of the signal light and / or Stokes light with a duty cycle below a preset threshold can, on the one hand, reduce the average power while maintaining a high pulse peak power, thereby reducing the thermal accumulation effect in the target sample and decreasing phototoxicity; on the other hand, it can be combined with appropriate demodulation techniques at the imaging detection end to suppress noise, improve the signal-to-noise ratio, and thus improve imaging quality. The preset threshold can be determined by those skilled in the art based on actual imaging requirements and a limited number of experiments.

[0069] Please refer to Figure 2 As shown, the present invention also provides a coherent anti-Stokes Raman scattering imaging device, including a driving light source 1, a beam splitter 2, an optical parametric amplifier 3, a first dispersion component 4, a beam combiner 5, a second dispersion component 6, and an imaging component. Figure 2 The black straight line in the diagram represents the optical path, and the black curve represents the electrical connection. Figures 2 to 6 The black arrow in the middle and Figure 8 The black arrows in the diagram all indicate the direction of light propagation.

[0070] Drive light source 1 to emit initial light. For example, drive light source 1 emits initial light with a wavelength of 1030 nm.

[0071] Beam splitter 2 is placed in the optical path of the initial light and is used to split the initial light into driving light and Stokes light. Figure 2 A beam splitter is used as beam splitter 2, but it is not limited to this. Those skilled in the art can also use other components as beam splitter 2, such as a combination of a half-wave plate and a polarizer.

[0072] The optical parametric amplifier 3 is placed in the optical path of the driving light and is used to process the driving light into signal light.

[0073] The first dispersion component 4 is disposed in the first optical path of the signal light and is used to perform pulse broadening processing on the signal light, or disposed in the second optical path of the Stokes light and is used to perform pulse broadening processing on the Stokes light. Figure 2 The example is that the first dispersive component 4 is placed in the second optical path of the Stokes light.

[0074] The beam combiner 5 is located at the end of the first and second optical paths and is used to combine the signal light and the Stokes light into the third optical path. Figure 2 A dichroic mirror is used as the beam combiner 5, but this is not a limitation. For example, based on... Figure 2 In the optical path shown, the dichroic mirror, which serves as the beam combiner 5, is configured to transmit Stokes light and reflect signal light.

[0075] The second dispersion component 6 is disposed in the third optical path and is used to perform pulse broadening processing on the signal light and Stokes light to obtain chirp-matched signal light and Stokes light.

[0076] An imaging component, positioned along the third optical path after the second dispersive component, is used to perform coherent anti-Stokes Raman scattering imaging of the target sample 7 based on chirp-matched signal light and Stokes light. Those skilled in the art can configure the imaging component with reference to existing technologies. This embodiment... Figure 2 The method provided is a preferred way to set up the imaging components. Figure 2 The imaging component consists of multiple parts, which will be explained in detail later.

[0077] The components of the imaging device described above can be understood by referring to the description in the imaging method above, and will not be repeated here. The imaging device described above can solve the problem that related technologies cannot simultaneously achieve both hyperspectral imaging speed and hyperspectral imaging quality.

[0078] Preferably, the first dispersion component 4 includes a first reflective element and a first dispersion element. The first reflective element is disposed at both ends of the first dispersion element. The first reflective element is configured to cause the signal light or Stokes light to repeatedly pass through the first dispersion element. The first dispersion element is configured to perform pulse broadening processing on the signal light or Stokes light.

[0079] The second dispersion component 6 includes a second reflective element and a second dispersion element. The second reflective element is disposed at both ends of the second dispersion element. The second reflective element is configured to allow the signal light and Stokes light to repeatedly pass through the second dispersion element. The second dispersion element is configured to perform pulse broadening processing on the signal light and Stokes light.

[0080] By setting the first reflective element and the second reflective element, the first dispersive element and the second dispersive element can be reused to the greatest extent, which helps to reduce the size of the imaging device and reduce the cost of the imaging device.

[0081] Furthermore, both the first and second reflecting elements include at least one of the following: a non-D-shaped mirror, a D-shaped mirror, a hollow roof prism, a polarizing beam-splitting cube mirror, and a quarter-wave plate; both the first and second dispersive elements include at least one of the following: a dispersive material, a grating, a prism, and a chirped mirror. The D-shaped mirror is a special structure mirror used to avoid reflected light, while the non-D-shaped mirror is a common mirror such as a circular mirror.

[0082] by Figures 3 to 6 For example, this embodiment will now specifically describe the first reflective element and the first dispersive element of the first dispersive assembly 4. Specifically, the following configuration is provided. Figures 3 to 6 The components shown are for pulse broadening of signal light or Stokes light, specifically using a design that reuses dispersive material 41. Dispersive material 41 can be, but is not limited to, optical glass or crystal. Optical glass, for example, SF57 optical glass or SF11 optical glass. Crystal, for example, zinc selenide crystal.

[0083] Figures 3 to 6 The diagram only shows the direction of signal light (first dispersive element 4 disposed in the first optical path) or Stokes light (first dispersive element 4 disposed in the second optical path) entering and exiting the first dispersive element 4. As for using different first dispersive elements 4, in order to... Figure 2 To maintain the same optical path, it may be necessary to introduce corresponding optical elements, such as mirrors, to change the optical path. This part belongs to the prior art and will not be described in detail in this embodiment.

[0084] Meanwhile, if the second reflective element and the second dispersive element of the second dispersive assembly 6 also adopt the design method of using multiple dispersive material 41, then it can be referred to Figures 3 to 6 The description of the first dispersive component 4 can be understood simply by replacing the signal light or Stokes beam incident on the first dispersive component 4 with the combined signal light and Stokes beam. Of course, since the objects undergoing pulse broadening processing are different, even if the first dispersive component 4 and the second dispersive component 6 use the same optical path structure design, the specific dimensions of their respective reflective and dispersive elements need to be adjusted to some extent. The method for determining these specific dimensions can be determined by those skilled in the art through a limited number of experiments.

[0085] For example, please refer to Figure 3As shown, the first reflecting element includes two hollow roof reflecting prisms: a first hollow roof reflecting prism 301 and a second hollow roof reflecting prism 302. The first dispersive element includes a dispersive material 41.

[0086] The first hollow roof ridge reflecting prism 301 and the second hollow roof ridge reflecting prism 302 are disposed on both sides of the dispersive material 41. The first hollow roof ridge reflecting prism 301 and the second hollow roof ridge reflecting prism 302 are configured to have a height difference in the X1 direction. The dispersive material 41 is configured such that its cross-section along the Y1 direction can cover the projection of the first hollow roof ridge reflecting prism 301 and the second hollow roof ridge reflecting prism 302 in the Y1 direction, so that the signal light (the first dispersive component 4 is disposed in the first optical path) or the Stokes light (the first dispersive component 4 is disposed in the second optical path) enters the dispersive material 41 along the Y1 direction from the side where the first hollow roof ridge reflecting prism 301 is located, and after multiple reflections, exits along the Y1 direction from the side where the second hollow roof ridge reflecting prism 302 is located.

[0087] Specifically, taking the placement of the first dispersive component 4 in the second optical path as an example, Stokes light enters the dispersive material 41 from the side where the first hollow roof reflecting prism 301 is located, and exits from the dispersive material 41 to the second hollow roof reflecting prism 302, which is the first use of the dispersive material 41; subsequently, the Stokes light reaches the second hollow roof reflecting prism 302, undergoes two reflections, and then enters the dispersive material 41 again, exiting from the dispersive material 41 to the first hollow roof reflecting prism 301, which is the second use of the dispersive material 41; subsequently, the Stokes light reaches the first hollow roof reflecting prism 301, undergoes two reflections, and then enters the dispersive material 41 again. The dispersive material 41 is used for the third time. The Stokes light reaches the second hollow roof reflecting prism 302, is reflected twice, and then enters the dispersive material 41 again. The light then exits the dispersive material 41 to the first hollow roof reflecting prism 301, which is used for the fourth time. The Stokes light reaches the first hollow roof reflecting prism 301, is reflected twice, and then enters the dispersive material 41 again. The light then exits the dispersive material 41 towards the side where the second hollow roof reflecting prism 302 is located, which is used for the fifth time.

[0088] Therefore, in Figure 3 In the first dispersive assembly 4 shown, which consists of a first hollow roof ridge reflecting prism 301, a second hollow roof ridge reflecting prism 302, and a dispersive material 41, the dispersive material 41 is reused five times, thus achieving five reuses of the dispersive material 41.

[0089] Of course, if the signal light or Stokes light is incident on the dispersive material 41 from the side where the second hollow roof reflecting prism 302 is located in the opposite direction of Y1, and after multiple reflections, it is also possible to exit from the side where the first hollow roof reflecting prism 301 is located in the opposite direction of Y1, thus achieving five reuses of the dispersive material 41.

[0090] in addition, Figure 3 The first reflecting element shown uses a first hollow roof reflecting prism 301 and a second hollow roof reflecting prism 302 to ensure that light can propagate in a parallel direction in the dispersive material 41. The advantages include: convenient industrial integration and optical path integration; the parallel propagation has little impact on the light spot mode, which helps to improve the imaging resolution (oblique incidence in actual laboratory settings easily destroys the Gaussian mode of the light spot, while the light spot mode of multiphoton microscopes has a greater impact on the imaging resolution).

[0091] For example, please refer to Figure 4 As shown, the first reflecting element includes two non-D-shaped mirrors and two D-shaped mirrors: a first D-shaped mirror 401, a second D-shaped mirror 402, a first non-D-shaped mirror 403, and a second non-D-shaped mirror 404. The first dispersive element includes a dispersive material 41.

[0092] The first non-D-shaped reflector 403 and the second non-D-shaped reflector 404 are disposed on both sides of the dispersive material 41. The dispersive material 41 is configured such that its cross-section along the X2 direction can cover the projection of the first non-D-shaped reflector 403 and the second non-D-shaped reflector 404 in the X2 direction. The first D-shaped reflector 401 and the second D-shaped reflector 402 are disposed between the first non-D-shaped reflector 403 and the dispersive material 41. The first D-shaped reflector 401 and the second D-shaped reflector 402 are symmetrically disposed with respect to the first non-D-shaped reflector 403 along the X2 direction axis of symmetry. The first D-shaped reflector 401 is configured to have an angle of less than 45 degrees with the Y2 direction, so that the signal light (the first dispersive component 4 is disposed in the first optical path) or the Stokes light (the first dispersive component 4 is disposed in the second optical path) is incident on the first D-shaped reflector 401 along the Y2 direction, reflected by the first D-shaped reflector 401 and enters the dispersive material 41. After multiple reflections, it is emitted from the second D-shaped reflector 402 along the Y2 direction.

[0093] Specifically, taking the first dispersive component 4 as an example of being placed in the second optical path, the Stokes light is reflected by the first D-shaped mirror 401, passes through the dispersive material 41, and reaches the second non-D-shaped mirror 404, which is the first use of the dispersive material 41; subsequently, the Stokes light is reflected by the second non-D-shaped mirror 404, passes through the dispersive material 41, and reaches the first non-D-shaped mirror 403, which is the second use of the dispersive material 41; subsequently, the Stokes light is reflected by the first non-D-shaped mirror 403, passes through the dispersive material 41, and reaches the second non-D-shaped mirror 404, which is the third use of the dispersive material 41; subsequently, the Stokes light is reflected by the second non-D-shaped mirror 404, passes through the dispersive material 41, and reaches the second D-shaped mirror 402, which is the fourth use of the dispersive material 41; subsequently, the Stokes light is emitted from the second D-shaped mirror 402 along the Y2 direction.

[0094] Therefore, in Figure 4 In the first dispersive assembly 4 shown, which consists of a first D-shaped reflector 401, a second D-shaped reflector 402, a first non-D-shaped reflector 403, a second non-D-shaped reflector 404, and a dispersive material 41, the dispersive material 41 is reused four times, thus realizing the four reuses of the dispersive material 41.

[0095] Of course, if the Stokes light is directed toward the second D-shaped mirror 402 in the opposite direction of Y2, and then reflected by the second D-shaped mirror 402 into the dispersive material 41, and after multiple reflections, it is also possible to exit from the first D-shaped mirror 401 in the opposite direction of Y2, thus achieving four reuses of the dispersive material 41.

[0096] in addition, Figure 4 The first reflective element shown uses a first D-shaped reflector 401 and a second D-shaped reflector 402, which has the advantages of simple and direct structure and low construction threshold.

[0097] For example, please refer to Figure 5 As shown, the first reflecting element includes a polarizing beam-splitting cube mirror, a quarter-wave plate, and a non-D-shaped mirror: the first polarizing beam-splitting cube mirror 501, the quarter-wave plate 502, and the third non-D-shaped mirror 503. The first dispersive element includes a dispersive material 41.

[0098] The first polarizing beam-splitting cubic mirror 501 and the third non-D-shaped mirror 503 are disposed on opposite sides of the dispersive material 41, and the quarter-wave plate 502 is disposed between the dispersive material 41 and the third non-D-shaped mirror 503. Signal light (the first dispersive component 4 is disposed in the first optical path) or Stokes light (the first dispersive component 4 is disposed in the second optical path) enters the dispersive material 41 along the X3 direction through the first polarizing beam-splitting cubic mirror 501, and after multiple reflections, exits from the first polarizing beam-splitting cubic mirror 501 along the Y3 direction.

[0099] Specifically, taking the first dispersive component 4 as an example of being placed in the second optical path, Stokes light is transmitted into the dispersive material 41 by the first polarizing beam-splitting cube mirror 501 along the X3 direction, and exits from the dispersive material 41 along the X3 direction, which is the first use of the dispersive material 41; subsequently, the Stokes light exiting from the dispersive material 41 passes through the quarter-wave plate 502 and reaches the third non-D-shaped mirror 503, and after being reflected by the third non-D-shaped mirror 503, the Stokes light passes through the quarter-wave plate 502 again and enters the dispersive material 41, exiting from the dispersive material 41 in the opposite direction of the X3 direction, which is the second use of the dispersive material 41; subsequently, the Stokes light exiting from the dispersive material 41 is reflected by the first polarizing beam-splitting cube mirror 501 and exits along the Y3 direction.

[0100] Therefore, in Figure 5 In the first dispersive assembly 4 shown, which consists of a first polarizing beam splitter cube mirror 501, a quarter-wave plate 502, a third non-D-shaped mirror 503, and a dispersive material 41, the dispersive material 41 is reused twice, thus realizing the double reuse of the dispersive material 41.

[0101] in addition, Figure 5 The first reflecting element shown uses a first polarizing beam-splitting cubic mirror 501 and a quarter-wave plate 502, which can make the trajectories of the round-trip rays in the dispersive material 41 coincide, thereby saving the cross-sectional area of ​​the dispersive material 41. In practical applications, it simplifies the process and reduces costs, and has good industrial value.

[0102] For example, please refer to Figure 6 As shown, in Figure 5 Based on the components shown, the first reflecting element also includes a hollow roof prism and a D-shaped reflector: a third hollow roof prism 601 and a third D-shaped reflector 602.

[0103] The third hollow roof reflecting prism 601 and the first polarizing beam-splitting cubic mirror 501 are positioned opposite each other along the Y3 direction. The Stokes light reflected by the first polarizing beam-splitting cubic mirror 501 is reflected twice, causing the Stokes light to travel in the opposite direction of the Y3 direction back towards the first polarizing beam-splitting cubic mirror 501. Subsequently, the Stokes light is reflected by the first polarizing beam-splitting cubic mirror 501 into the dispersive material 41 and exits along the X3 direction, representing the third use of the dispersive material 41. Then… Stokes light emitted from dispersive material 41 passes through quarter-wave plate 502 and reaches third non-D-shaped mirror 503. After being reflected by third non-D-shaped mirror 503, Stokes light passes through quarter-wave plate 502 again and enters dispersive material 41. It exits from dispersive material 41 in the opposite direction of X3, which is the fourth use of dispersive material 41. Subsequently, Stokes light emitted from dispersive material 41 is transmitted by first polarizing beam splitter cube mirror 501 and exits in the opposite direction of X3.

[0104] The third D-shaped reflector 602 is disposed on the side of the first polarizing beam splitter 501 away from the dispersive material 41, and reflects the Stokes light transmitted by the first polarizing beam splitter 501 so that the Stokes light is emitted along the Y3 direction.

[0105] in other words, Figure 6 The third D-shaped reflector 602 is set in order to direct the Stokes light emitted from the first dispersive component 4 in the same direction as... Figure 5 The middle Stokes light emitted from the first dispersive component 4 is in the same direction. If the sole purpose is to achieve four reuses of the dispersive material 41, then... Figure 5 Based on the components shown, only a third hollow roof ridge reflecting prism 601 is added, without the third D-shaped reflecting mirror 602. In this case, the Stokes light emitted from the first dispersive component 4 is in the opposite direction to the X3 direction.

[0106] In this embodiment, the first reflecting element may be one or more of the following: a non-D-shaped mirror, a D-shaped mirror, a hollow roof prism, a polarizing beam-splitting cube mirror, and a quarter-wave plate. The specific number of the first reflecting element is at least two. The first dispersive element may be one or more of the following: a dispersive material, a grating, a prism, and a chirped mirror.

[0107] The descriptions of the second reflecting element and the second dispersive element can be found in the descriptions of the first reflecting element and the first dispersive element, and will not be repeated in this embodiment. The arrangement of the second reflecting element and the second dispersive element, i.e., the arrangement of the second dispersive component 6, can be the same as or different from the arrangement of the first reflecting element and the first dispersive element, i.e., the arrangement of the first dispersive component 4. Preferably, in this embodiment, both the arrangement of the first dispersive component 4 and the arrangement of the second dispersive component 6 utilize multiplexed dispersive materials, enabling the achievement of millions of fs using only tens of centimeters of dispersive material (which, after multiplexing, can be equivalent to several meters of dispersive material). 2 The group delay dispersion of the order of magnitude broadens the femtosecond pulse into a linear chirped pulse of tens of picoseconds.

[0108] Preferably, please refer to Figure 2 As shown, the imaging device further includes a first delay line assembly 8 and / or a second delay line assembly 9; the first delay line assembly 8 is disposed in the first optical path and is used to adjust the optical path of the signal light; the second delay line assembly 9 is disposed in the second optical path and is used to adjust the optical path of the Stokes light.

[0109] The purpose of setting the first delay line component 8 and / or the second delay line component 9 is to adjust the optical path difference between the signal light and the Stokes light in the imaging system so that the sum of the initial optical path difference between the signal light and the Stokes light and the optical path difference between the signal light and the Stokes light in the imaging system is 0.

[0110] If only the first delay line component 8 is set, the optical path of the signal light in the imaging system can only be adjusted, which is suitable for situations where the optical path of the signal light in the imaging system is less than that of the Stokes light in the imaging system.

[0111] If only the second delay line component 9 is set, the optical path of the Stokes beam in the imaging system can be adjusted, which is suitable for situations where the optical path of the signal beam in the imaging system is greater than that of the Stokes beam in the imaging system.

[0112] By simultaneously setting up the first delay line component 8 and the second delay line component 9, the optical path length of the signal light and the optical path length of the Stokes light in the imaging system can be adjusted, thereby achieving better applicability by increasing the number of components.

[0113] The first delay line assembly 8 and the second delay line assembly 9 may specifically include, but are not limited to: an electrically adjustable delay line based on a motor-driven translation stage, a manually adjustable delay line based on a manually operated knob-driven translation stage, a piezoelectric ceramic delay line that uses the inverse piezoelectric effect of piezoelectric ceramics to drive the translation of a reflector, and an electro-optic delay line that uses the electro-optic effect of electro-optic crystals to change the refractive index of the crystal.

[0114] Preferably, the imaging device further includes a first beam expander and / or a second beam expander; the first beam expander is disposed in the first optical path for adjusting the size of the signal light; the second beam expander is disposed in the second optical path for adjusting the size of the Stokes beam.

[0115] Considering that the optical path of the signal light and Stokes light in the imaging system may be relatively long, especially when both the first dispersion component 4 and the second dispersion component 6 adopt the design of multiplexed dispersion material 41, it is necessary to expand the signal light and Stokes light so that they do not diverge when traveling a long optical path.

[0116] The size adjustment of the signal beam using the first beam expander mainly involves adjusting the beam waist diameter, but is not limited to this. Similarly, the size adjustment of the Stokes beam using the second beam expander also mainly involves adjusting the beam waist diameter, but is not limited to this.

[0117] Preferably, please refer to Figure 8 As shown, the first beam expander includes a first convex lens 10, a first concave lens 11, and a second convex lens 12, with the first concave lens 11 disposed between the first convex lens 10 and the second convex lens 12. The second beam expander includes a third convex lens 13, a second concave lens 14, and a fourth convex lens 15, with the second concave lens 14 disposed between the third convex lens 13 and the fourth convex lens 15.

[0118] The positions of the first convex lens 10 and the second convex lens 12 remain unchanged. The beam expansion ratio of the first beam expander can be changed by adjusting the position of the first concave lens 11. Similarly, the positions of the third convex lens 13 and the fourth convex lens 15 remain unchanged. The beam expansion ratio of the second beam expander can be changed by adjusting the position of the second concave lens 14.

[0119] Considering the potential variation in the size of the signal light output by the optical parametric amplifier, and the difference between the signal light and the initial light emitted by the driving light source, the following settings are made: Figure 8 The first and second beam expanders shown can significantly improve the adaptability of the imaging device to the output light source of the optical parametric amplifier.

[0120] certainly, Figure 8 The first and second beam expanders shown are only preferred examples. Those skilled in the art can also use other components to form the first and second beam expanders, which will not be described in detail here.

[0121] Preferably, the imaging device further includes a first optical modulator 16 and / or a second optical modulator 17; the first optical modulator 16 is disposed in the first optical path and is used to modulate the intensity of the signal light with a duty cycle lower than a preset threshold; the second optical modulator 17 is disposed in the second optical path and is used to modulate the intensity of the Stokes light with a duty cycle lower than a preset threshold. For example, Figure 2 and Figure 8 Both are equipped with a first optical modulator 16 and a second optical modulator 17.

[0122] The aforementioned preset threshold can be, but is not limited to, 10%.

[0123] The modulation parameters of the first optical modulator 16 and the second optical modulator 17 are in the range of hundreds of kHz to several MHz. Those skilled in the art can select them based on the repetition frequency and relative intensity noise spectrum distribution of the optical parametric amplifier itself.

[0124] In the imaging device provided in this embodiment, intensity modulation of the signal light and / or Stokes light with a duty cycle lower than a preset threshold can reduce the average power while ensuring a high pulse peak power, thereby reducing the thermal accumulation effect in the target sample 7 and reducing phototoxicity. Furthermore, it can be combined with corresponding demodulation technology at the detection end of the imaging component to further suppress noise and improve the signal-to-noise ratio.

[0125] Considering that the aperture of an optical modulator is generally small, the light entering the optical modulator needs to be approximately parallel, therefore... Figure 2 When the first and second beam expanders are combined, the first optical modulator 16 is disposed between the first concave lens 11 and the second convex lens 12, and the second optical modulator 17 is disposed between the second concave lens 14 and the fourth convex lens 15. Specifically, the first optical modulator 16 is disposed at the object-side focal point of the second convex lens 12, and the second optical modulator 17 is disposed at the object-side focal point of the fourth convex lens 15.

[0126] Preferably, please refer to Figure 2 and Figure 8 As shown, the imaging components of the imaging device include a dichroic mirror 18, a scanning galvanometer 19, an objective lens 20, a condenser lens 21, a first detector 22, a data acquisition card 23, a computer 24, and a second detector 25. The scanning galvanometer 19, the first detector 22, the computer 24, and the second detector 25 are all electrically connected to the data acquisition card 23. The scanning galvanometer 19 receives drive signals from the data acquisition card 23, and the data acquisition card 23 receives analog-to-digital signals from the first detector 22 and the second detector 25 and transmits them to the computer 24.

[0127] A dichroic mirror 18 is disposed between the second dispersive assembly 6 and the scanning mirror 19 to transmit the signal light and Stokes light emitted from the second dispersive assembly 6 into the scanning mirror 19. The reflection effect of the dichroic mirror 18 will be described later.

[0128] The scanning galvanometer 19 forms a scanning beam based on the incident signal light and Stokes light, and scans the surface of the target sample 7 to achieve rapid point-by-point imaging and obtain high-resolution three-dimensional morphology. For example, the bandwidth of the scanning galvanometer 19 is 0-1kHz. Appropriately lowering the threshold will reduce the imaging speed, but will not affect the imaging principle and imaging quality.

[0129] An objective lens 20 is positioned between the scanning galvanometer 19 and the target sample 7, with the target sample 7 located on the focal plane of the objective lens 20. The objective lens 20 can focus the scanning beam output from the scanning galvanometer 19, improving image quality. Specifically, the objective lens 20 needs to be achromatic to ensure that the signal light and Stokes light are focused onto the same plane.

[0130] The first detector 22 is located on the side of the target sample 7 away from the scanning galvanometer 19. It is used to receive part of the scattered light generated by the scanning beam acting on the target sample 7 and convert it into a processable electrical signal, which is then sent to the acquisition card 23.

[0131] The condenser lens 21 is positioned between the target sample 7 and the first detector 22, which helps the first detector 22 capture more scattered light.

[0132] Specifically, the relative position of the condenser lens 21 and the target sample 7 is determined by the Kohler illumination conditions to ensure that the condenser lens 21 can collect sufficient light. Of course, imaging results can still be obtained even if the condenser lens 21 does not collect sufficient light, but the effect will be slightly worse.

[0133] The relative positions of the condenser lens 21 and the first detector 22 should satisfy the condition that the first detector 22 is located near the rear focal point of the condenser lens 21, so as to ensure that the first detector 22 can fully collect the light gathered by the condenser lens 21. Herein, the rear focal point of the condenser lens 21 refers to the focal point of the condenser lens 21 on the side closer to the first detector 22.

[0134] Meanwhile, the condenser lens 21 can also be replaced with other elements that have a light-concentrating function, such as lenses, objective lenses, or optical fibers.

[0135] The scattered light generated by the scanning beam acting on the target sample 7 will be directed in multiple directions. The scattered light that travels along the objective lens 20 to the scanning galvanometer 19 will be reflected by the dichroic mirror 18 to the second detector 25 when it propagates through the scanning galvanometer 19 to the second dispersive component 6. The second detector 25 will then convert the light into a processable electrical signal and send it to the acquisition card 23.

[0136] In other words, in this embodiment, the dichroic mirror 18 is configured to transmit the signal light and Stokes light and reflect the scattered light propagating from the scanning mirror 19.

[0137] Since the scattered light reflected by the dichroic mirror 18 passes through the objective lens 20 and then the scanning galvanometer 19, the objective lens 20 acts as a focusing lens for the scattered light, making the scattered light relatively parallel when it hits the second detector 25. Therefore, there is no need to place a focusing element between the dichroic mirror 18 and the second detector 25.

[0138] Specifically, the scanning galvanometer 19 is positioned above the target sample 7, and the first detector 22 is positioned below the target sample 7. Therefore, the first detector 22 mainly collects the scattered light below the target sample 7, while the second detector 25 mainly collects the scattered light above the target sample 7.

[0139] When the transmittance of the target sample 7 is low, such as when the target sample 7 is a biological sample rich in pigment, a multiphase mixed sample, or a sample with an irregular surface, setting up a second detector 25 to collect the scattered light above the target sample 7 can improve the imaging quality.

[0140] In other words, forward scattering imaging is performed by using a condenser lens 21 and a first detector 22 to collect light, and backscattering imaging is performed by using a second detector 25 to detect backscattered light. Each of these two imaging methods has its own advantages: forward scattering imaging is generally stronger than backscattering imaging, but for samples with low transparency or thicker samples, forward scattered photons will gradually attenuate, and backscattering imaging is more advantageous in this case.

[0141] In simple terms, forward scattering imaging and backscattering imaging are complementary. Both imaging methods can reflect the chemical imaging information of a substance. In this embodiment, it is not limited to performing forward scattering imaging and backscattering imaging simultaneously.

[0142] Preferably, the imaging device further includes a first reflector 26, a second reflector 27, a third reflector 28, and a fourth reflector 29.

[0143] A first reflecting mirror 26 is disposed between the beam splitter 2 and the first dispersive assembly 4, for directing Stokes light toward the first dispersive assembly 4. Figure 2 In the preferred embodiment shown, the first reflector 26 is specifically disposed between the beam splitter 2 and the second optical modulator 17. Figure 8 In the preferred embodiment shown, the first reflector 26 is specifically disposed between the beam splitter 2 and the third convex lens 13.

[0144] The second reflector 27 is positioned between the optical parametric amplifier and the beam combiner 5 to direct the signal light toward the beam combiner 5. Figure 2 and Figure 8 In the preferred embodiment shown, the second reflector 27 is specifically disposed between the first delay line assembly 8 and the beam combiner 5.

[0145] exist Figure 2 and Figure 8 In the preferred embodiment shown, the third reflector 28 and the fourth reflector 29 are sequentially disposed between the beam combiner 5 and the second dispersion component 6, for directing the combined signal light and Stokes light toward the second dispersion component 6.

[0146] Those skilled in the art can also use other optical elements to adjust the propagation direction of the signal light and / or Stokes light to set up the first, second and third optical paths that meet the actual application requirements. This embodiment will not be described in detail here.

[0147] It should be noted that the term "comprising" and its variations used in the embodiments of this invention are open-ended, meaning "including but not limited to". The term "based on" means "at least partially based on". The term "one embodiment" means "at least one embodiment"; the term "another embodiment" means "at least one additional embodiment"; the term "some embodiments" means "at least some embodiments". The modifications of "one" and "a plurality" mentioned in the embodiments of this invention are illustrative and not restrictive, and those skilled in the art should understand that unless explicitly indicated otherwise in the context, they should be understood as "one or more". The descriptions of terms such as "first", "second", etc., are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of indicated technical features.

[0148] The steps described in the method embodiments provided by the present invention can be performed in different orders and / or in parallel. Furthermore, the method embodiments may include additional steps and / or omit the steps shown. The scope of protection of the present invention is not limited in this respect.

[0149] The term "embodiment" in this specification refers to a specific feature, structure, or characteristic described in connection with an embodiment that may be included in at least one embodiment of the invention. The appearance of this phrase in various places throughout the specification does not necessarily imply the same embodiment, nor does it imply independence or alternativeity from other embodiments. The various embodiments in this specification are described in a related manner, with reference to each other for similar or identical parts. In particular, for apparatus, device, and system embodiments, since they are substantially similar to method embodiments, the description is relatively simple, and relevant details are referred to in the description of the method embodiments.

[0150] The above-described embodiments are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of protection. It should be noted that those skilled in the art can make various modifications and improvements without departing from the inventive concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the appended claims.

Claims

1. A coherent anti-Stokes Raman scattering imaging method, characterized in that, include: The initial light emitted by the driving light source is split into driving light and Stokes light; The driving light is processed into signal light based on an optical parametric amplifier; In the first optical path of the signal light, the signal light is pulse-stretched based on the first dispersion component; or, in the second optical path of the Stokes light, the Stokes light is pulse-stretched based on the first dispersion component. The signal light and the Stokes light are combined into a third optical path. On the third optical path, the signal light and the Stokes light are pulse-stretched based on a second dispersion component to obtain a chirped signal light and a Stokes light. Based on the chirped rate-matched signal light and Stokes light, coherent anti-Stokes Raman scattering imaging is performed on the target sample; The first dispersion component includes a first reflective element and a first dispersion element. The first reflective element is disposed at both ends of the first dispersion element, and the first reflective element is configured to cause the signal light or the Stokes light to repeatedly pass through the first dispersion element. The second dispersion component includes a second reflective element and a second dispersion element. The second reflective element is disposed at both ends of the second dispersion element, and the second reflective element is configured to cause the signal light and the Stokes light to repeatedly pass through the second dispersion element. The first reflecting element includes a first D-shaped reflector (401), a second D-shaped reflector (402), a first non-D-shaped reflector (403), and a second non-D-shaped reflector (404), and the first dispersive element includes a dispersive material (41). The first non-D-shaped reflector (403) and the second non-D-shaped reflector (404) are disposed on both sides of the dispersive material (41). The dispersive material (41) is configured such that its cross-section along the X2 direction can cover the projection of the first non-D-shaped reflector (403) and the second non-D-shaped reflector (404) in the X2 direction. The first D-shaped reflector (401) and the second D-shaped reflector (402) are disposed between the first non-D-shaped reflector (403) and the dispersive material (41). 01) The second D-shaped reflector (402) is symmetrically arranged with respect to the first non-D-shaped reflector (403) along the axis of symmetry in the X2 direction. The first D-shaped reflector (401) is set to have an angle of less than 45 degrees with the Y2 direction so that the signal light or Stokes light is directed towards the first D-shaped reflector (401) in the Y2 direction, and after being reflected by the first D-shaped reflector (401), it enters the dispersive material (41). After multiple reflections, it is emitted from the second D-shaped reflector (402) in the Y2 direction. In this process, the signal light or Stokes light is reflected by the first D-shaped mirror (401), passes through the dispersive material (41), and reaches the second non-D-shaped mirror (404), which is the first use of the dispersive material (41); subsequently, the signal light or Stokes light is reflected by the second non-D-shaped mirror (404), passes through the dispersive material (41), and reaches the first non-D-shaped mirror (403), which is the second use of the dispersive material (41); subsequently, the signal light or Stokes light is reflected by the first non-D-shaped mirror (403), passes through the dispersive material (41), and reaches the second non-D-shaped mirror (404), which is the third use of the dispersive material (41); subsequently, the signal light or Stokes light is reflected by the second non-D-shaped mirror (404), passes through the dispersive material (41), and reaches the second D-shaped mirror (402), which is the fourth use of the dispersive material (41); subsequently, the signal light or Stokes light is emitted from the second D-shaped mirror (402) along the Y2 direction.

2. The method according to claim 1, characterized in that, Before combining the signal light and the Stokes beam into the third optical path, the method further includes: The optical path of the signal light is adjusted in the first optical path, and / or the optical path of the Stokes light is adjusted in the second optical path, until the optical path of the signal light and the optical path of the Stokes light are matched.

3. The method according to claim 1, characterized in that, Before combining the signal light and the Stokes beam into the third optical path, the method further includes: The signal light is subjected to intensity modulation with a duty cycle lower than a preset threshold on the first optical path, and / or the Stokes light is subjected to intensity modulation with a duty cycle lower than the preset threshold on the second optical path.

4. A coherent anti-Stokes Raman scattering imaging device, characterized in that, include: Drive the light source to emit initial light; A beam splitter is disposed in the optical path of the initial light to split the initial light into a driving light and a Stokes light; An optical parametric amplifier is disposed in the optical path of the driving light and is used to process the driving light into signal light; A first dispersion component is disposed in the first optical path of the signal light for pulse broadening processing of the signal light, or disposed in the second optical path of the Stokes light for pulse broadening processing of the Stokes light; A beam combiner, located at the ends of the first and second optical paths, is used to combine the signal light and the Stokes light into a third optical path; A second dispersion component is disposed in the third optical path to perform pulse broadening processing on the signal light and the Stokes light to obtain a chirped signal light and a Stokes light. An imaging component, disposed after the second dispersion component along the third optical path, is used to perform coherent anti-Stokes Raman scattering imaging of a target sample based on the chirped signal light and Stokes light; the first dispersion component includes a first reflective element and a first dispersion element, the first reflective element being disposed at both ends of the first dispersion element, and the first reflective element being configured to cause the signal light or the Stokes light to repeatedly pass through the first dispersion element. The second dispersion component includes a second reflective element and a second dispersion element. The second reflective element is disposed at both ends of the second dispersion element, and the second reflective element is configured to cause the signal light and the Stokes light to repeatedly pass through the second dispersion element. The first reflecting element includes a first D-shaped reflector (401), a second D-shaped reflector (402), a first non-D-shaped reflector (403), and a second non-D-shaped reflector (404), and the first dispersive element includes a dispersive material (41). The first non-D-shaped reflector (403) and the second non-D-shaped reflector (404) are disposed on both sides of the dispersive material (41). The dispersive material (41) is configured such that its cross-section along the X2 direction can cover the projection of the first non-D-shaped reflector (403) and the second non-D-shaped reflector (404) in the X2 direction. The first D-shaped reflector (401) and the second D-shaped reflector (402) are disposed between the first non-D-shaped reflector (403) and the dispersive material (41). 01) The second D-shaped reflector (402) is symmetrically arranged with respect to the first non-D-shaped reflector (403) along the axis of symmetry in the X2 direction. The first D-shaped reflector (401) is set to have an angle of less than 45 degrees with the Y2 direction so that the signal light or Stokes light is directed towards the first D-shaped reflector (401) in the Y2 direction, and after being reflected by the first D-shaped reflector (401), it enters the dispersive material (41). After multiple reflections, it is emitted from the second D-shaped reflector (402) in the Y2 direction. In this process, the signal light or Stokes light is reflected by the first D-shaped mirror (401), passes through the dispersive material (41), and reaches the second non-D-shaped mirror (404), which is the first use of the dispersive material (41); subsequently, the signal light or Stokes light is reflected by the second non-D-shaped mirror (404), passes through the dispersive material (41), and reaches the first non-D-shaped mirror (403), which is the second use of the dispersive material (41); subsequently, the signal light or Stokes light is reflected by the first non-D-shaped mirror (403), passes through the dispersive material (41), and reaches the second non-D-shaped mirror (404), which is the third use of the dispersive material (41); subsequently, the signal light or Stokes light is reflected by the second non-D-shaped mirror (404), passes through the dispersive material (41), and reaches the second D-shaped mirror (402), which is the fourth use of the dispersive material (41); subsequently, the signal light or Stokes light is emitted from the second D-shaped mirror (402) along the Y2 direction.

5. The apparatus according to claim 4, characterized in that, It also includes a first delay line assembly and / or a second delay line assembly; The first delay line component is disposed on the first optical path and is used to adjust the optical path of the signal light; The second delay line assembly is disposed in the second optical path and is used to adjust the optical path of the Stokes light.

6. The apparatus according to claim 4, characterized in that, It also includes a first beam expander assembly and / or a second beam expander assembly; The first beam expander is disposed on the first optical path and is used to adjust the size of the signal light; The second beam expander is disposed in the second optical path and is used to adjust the size of the Stokes beam.

7. The apparatus according to claim 4, characterized in that, It also includes a first optical modulator and / or a second optical modulator; The first optical modulator is disposed on the first optical path and is used to perform intensity modulation on the signal light with a duty cycle lower than a preset threshold. The second optical modulator is disposed on the second optical path and is used to modulate the intensity of the Stokes light with a duty cycle lower than the preset threshold.

8. A coherent anti-Stokes Raman scattering imaging device, characterized in that, include: Drive the light source to emit initial light; A beam splitter is disposed in the optical path of the initial light to split the initial light into a driving light and a Stokes light; An optical parametric amplifier is disposed in the optical path of the driving light and is used to process the driving light into signal light; A first dispersion component is disposed in the first optical path of the signal light for pulse broadening processing of the signal light, or disposed in the second optical path of the Stokes light for pulse broadening processing of the Stokes light; A beam combiner, located at the ends of the first and second optical paths, is used to combine the signal light and the Stokes light into a third optical path; A second dispersion component is disposed in the third optical path to perform pulse broadening processing on the signal light and the Stokes light to obtain a chirped signal light and a Stokes light. An imaging component, disposed along the third optical path after the second dispersive component, is used to perform coherent anti-Stokes Raman scattering imaging of the target sample based on the chirped signal light and Stokes light. The first dispersion component includes a first reflective element and a first dispersion element. The first reflective element is disposed at both ends of the first dispersion element, and the first reflective element is configured to cause the signal light or the Stokes light to repeatedly pass through the first dispersion element. The second dispersion component includes a second reflective element and a second dispersion element. The second reflective element is disposed at both ends of the second dispersion element, and the second reflective element is configured to cause the signal light and the Stokes light to repeatedly pass through the second dispersion element. The first reflecting element includes a first hollow roof reflecting prism (301) and a second hollow roof reflecting prism (302), and the first dispersive element includes a dispersive material (41). The first hollow roof ridge reflecting prism (301) and the second hollow roof ridge reflecting prism (302) are disposed on both sides of the dispersive material (41). The first hollow roof ridge reflecting prism (301) and the second hollow roof ridge reflecting prism (302) are configured to have a height difference in the X1 direction. The dispersive material (41) is configured such that its cross section along the Y1 direction can cover the projection of the first hollow roof ridge reflecting prism (301) and the second hollow roof ridge reflecting prism (302) in the Y1 direction, so that the signal light or Stokes light enters the dispersive material (41) along the Y1 direction from the side where the first hollow roof ridge reflecting prism (301) is located, and after multiple reflections, it exits along the Y1 direction from the side where the second hollow roof ridge reflecting prism (302) is located. The signal light or Stokes light enters the dispersive material (41) from the side where the first hollow roof reflecting prism (301) is located, and exits from the dispersive material (41) to the second hollow roof reflecting prism (302), which is the first use of the dispersive material (41); subsequently, the signal light or Stokes light reaches the second hollow roof reflecting prism (302), and after two reflections, enters the dispersive material (41) again, and exits from the dispersive material (41) to the first hollow roof reflecting prism (301), which is the second use of the dispersive material (41); subsequently, the signal light or Stokes light reaches the first hollow roof reflecting prism (301), and after two reflections, enters the dispersive material (41) again, and exits from the dispersive material... The material (41) is emitted to the second hollow roof reflecting prism (302), which is the third use of the dispersive material (41); then, the signal light or Stokes light reaches the second hollow roof reflecting prism (302), and after two reflections, it is emitted into the dispersive material (41) again, and then emitted from the dispersive material (41) to the first hollow roof reflecting prism (301), which is the fourth use of the dispersive material (41); then, the signal light or Stokes light reaches the first hollow roof reflecting prism (301), and after two reflections, it is emitted into the dispersive material (41) again, and then emitted from the dispersive material (41) to the side where the second hollow roof reflecting prism (302) is located, which is the fifth use of the dispersive material (41).

9. A coherent anti-Stokes Raman scattering imaging device, characterized in that, include: Drive the light source to emit initial light; A beam splitter is disposed in the optical path of the initial light to split the initial light into a driving light and a Stokes light; An optical parametric amplifier is disposed in the optical path of the driving light and is used to process the driving light into signal light; A first dispersion component is disposed in the first optical path of the signal light for pulse broadening processing of the signal light, or disposed in the second optical path of the Stokes light for pulse broadening processing of the Stokes light; A beam combiner, located at the ends of the first and second optical paths, is used to combine the signal light and the Stokes light into a third optical path; A second dispersion component is disposed in the third optical path to perform pulse broadening processing on the signal light and the Stokes light to obtain a chirped signal light and a Stokes light. An imaging component, disposed along the third optical path after the second dispersive component, is used to perform coherent anti-Stokes Raman scattering imaging of the target sample based on the chirped signal light and Stokes light. The first dispersion component includes a first reflective element and a first dispersion element. The first reflective element is disposed at both ends of the first dispersion element, and the first reflective element is configured to cause the signal light or the Stokes light to repeatedly pass through the first dispersion element. The second dispersion component includes a second reflective element and a second dispersion element. The second reflective element is disposed at both ends of the second dispersion element, and the second reflective element is configured to cause the signal light and the Stokes light to repeatedly pass through the second dispersion element. The first reflecting element includes a first polarizing beam splitter cube mirror (501), a quarter-wave plate (502), and a third non-D-shaped mirror (503); the first dispersive element includes a dispersive material (41). The first polarizing beam splitter (501) and the third non-D-shaped mirror (503) are disposed on both sides of the dispersive material (41), and the quarter-wave plate (502) is disposed between the dispersive material (41) and the third non-D-shaped mirror (503); the signal light or Stokes light enters the dispersive material (41) through the first polarizing beam splitter (501) along the X3 direction, and after multiple reflections, it exits from the first polarizing beam splitter (501) along the Y3 direction; The signal light or Stokes light is transmitted into the dispersive material (41) by the first polarizing beam splitter (501) along the X3 direction, and exits from the dispersive material (41) along the X3 direction, which is the first use of the dispersive material (41); then, the signal light or Stokes light emitted from the dispersive material (41) passes through the quarter-wave plate (502) and reaches the third non-D-shaped mirror (503). After being reflected by the third non-D-shaped mirror (503), the signal light or Stokes light passes through the quarter-wave plate (502) and enters the dispersive material (41) again, and exits from the dispersive material (41) in the opposite direction of the X3 direction, which is the second use of the dispersive material (41); then, the signal light or Stokes light emitted from the dispersive material (41) is reflected by the first polarizing beam splitter (501) and exits along the Y3 direction.

10. The apparatus according to claim 9, characterized in that, The first reflecting element also includes a third hollow roof ridge reflecting prism (601) and a third D-shaped reflecting mirror (602). The third hollow roof reflecting prism (601) and the first polarizing beam-splitting cube mirror (501) are positioned opposite each other along the Y3 direction. The Stokes light reflected by the first polarizing beam-splitting cube mirror (501) is reflected twice, causing the Stokes light to travel in the opposite direction of the Y3 direction towards the first polarizing beam-splitting cube mirror (501). Subsequently, the Stokes light is reflected by the first polarizing beam-splitting cube mirror (501) into the dispersive material (41) and exits along the X3 direction, marking the third use of the dispersive material (41). Following this, the light exits from the dispersive material (41) along the X3 direction... Stokes light emitted from the dispersive material (41) passes through a quarter-wave plate (502) and reaches the third non-D-shaped mirror (503). After being reflected by the third non-D-shaped mirror (503), the Stokes light passes through the quarter-wave plate (502) and enters the dispersive material (41) again. It exits from the dispersive material (41) in the opposite direction of the X3 direction, which is the fourth use of the dispersive material (41). Subsequently, the Stokes light emitted from the dispersive material (41) is transmitted by the first polarizing beam splitter (501) and exits in the opposite direction of the X3 direction. The third D-shaped reflector (602) is positioned on the side of the first polarizing beam splitter (501) away from the dispersive material (41) to reflect the Stokes light transmitted by the first polarizing beam splitter (501) so that the Stokes light is emitted along the Y3 direction.

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