A complementary Bessel droplet two-photon microscopy system

Abstract

The invention discloses a complementary Bessel light droplet two-photon microscopic imaging system, comprising: an excitation light source module, a Bessel light droplet modulation module, a two-photon microscopic imaging module, a spatial light modulator control module, and a signal acquisition / imaging and synchronization control module; the complementary Bessel light droplet two-photon microscopic imaging system provided by the invention generates two coaxial Bessel light beams with different NAs through a first spatial light modulator and a second spatial light modulator in the Bessel light droplet modulation module and simultaneously introduces different phase differences, so that the Bessel light droplets formed by the interference of the coaxial double Bessel light beams with a phase difference of #imgabs0# and the Bessel light droplets formed by the interference of the coaxial double Bessel light beams with a phase difference of #imgabs1# are offset in the axial light field distribution, so as to obtain complementary Bessel light droplets, which are used to excite a two-photon fluorescence microscopic imaging system, and realize rapid, high-contrast and high-spatial-resolution volume imaging of biological tissues.

Description

Technical Field

[0001] The invention belongs to the technical field of two-photon microscopic imaging, and in particular relates to a complementary Bessel light droplet two-photon microscopic imaging system. Background Art

[0002] Traditional two-photon fluorescence microscopy systems use Gaussian beam excitation, which requires z-axis scanning during volume imaging, resulting in slow imaging speed. Bessel beams have unique non-diffraction and self-healing properties. The non-diffraction property means that it has the property of maintaining its lateral light field distribution over a long propagation distance, and the self-healing property means that after encountering an obstacle during the propagation process, it can restore its original lateral light field distribution after a certain distance. Therefore, two-photon fluorescence microscopy based on Bessel beam excitation has the characteristics of long depth of field and less influence by scattering, so that fast volume imaging can be achieved. For sparsely labeled biological tissues, it can achieve an imaging throughput several dozen times higher than that of traditional Gaussian beam excitation two-photon microscopy, and realize volume imaging at a two-dimensional frame rate.

[0003] However, since there are a series of concentric rings, i.e. side lobes, around the central spot of the Bessel beam, and the energy share is high, a strong background will be generated, thereby reducing the contrast of the imaging. The current methods for suppressing the side lobes of Bessel beams mainly include confocal line detection, high-order nonlinear effects, image difference method, and light droplet method. Bessel light droplets use the interference of two coaxial Bessel beams of different NA to form a standing wave, thereby achieving the effect of suppressing side lobes, thereby solving the problem of low contrast of two-photon fluorescence microscopy imaging excited by Bessel beams. However, while suppressing the side lobe energy, Bessel light droplets will produce the phenomenon of alternating light and dark in the axial light field distribution, making it difficult to use in two-photon fluorescence microscopy systems. Summary of the invention

[0004] The present invention provides a complementary Bessel droplet two-photon microscopy system, aiming to solve the problem that the current two-photon fluorescence microscopy system cannot solve the phenomenon that the axial light field distribution will alternate between light and dark while suppressing the side lobe energy by using the Bessel droplet technology, thus affecting the observation results of the two-photon fluorescence microscopy system.

[0005] The present invention is implemented as follows: a complementary Bessel light droplet two-photon microscopic imaging system is applied to microscopic imaging of a sample to be tested, comprising:

[0006] Excitation light source module; the excitation light source module generates a horizontal polarization state light beam and a vertical polarization state light beam by polarization beam splitting;

[0007] Bessel light droplet modulation module, the Bessel light droplet modulation module modulates the horizontal polarization state light beam into a phase difference The first Bessel light droplet is formed by the interference of the coaxial double Bessel light beams; at the same time, the vertical polarization state light beam is modulated into a phase difference The first Bessel light droplet and the second Bessel light droplet are combined to form a complementary Bessel light droplet, and the Fourier spectrum of the first Bessel light droplet and the second Bessel light droplet is generated and the stray light thereof is filtered out;

[0008] A two-photon microscopic imaging module, wherein the complementary Bessel light droplets are focused on the sample to be measured through the two-photon microscopic imaging module to realize point scanning, and the two-photon microscopic imaging module collects the backscattered fluorescence signal generated by the sample after two-photon excitation and converts it into a voltage signal;

[0009] A spatial light modulator control module, the spatial light modulator control module is electrically connected to the Bessel light droplet modulation module, and calculates and loads a phase pattern required on the Bessel light droplet modulation module;

[0010] The signal acquisition / imaging and synchronization control module controls the synchronization of the output and acquisition of the fluorescence signal, and reconstructs the two-photon intensity map of the obtained voltage signal.

[0011] Preferably, the Bessel light droplet modulation module comprises:

[0012] A first spatial light modulator and a second spatial light modulator; the horizontally polarized light beam passes through the first spatial light modulator to generate a first Bessel light droplet, and the vertically polarized light beam passes through the second spatial light modulator to generate a second Bessel light droplet;

[0013] A second polarization beam splitter, wherein the first Bessel light droplet and the second Bessel light droplet in different polarization states are combined through the second polarization beam splitter to obtain a Bessel light beam with uniform axial light field distribution and suppressed side lobes, that is, complementary Bessel light droplets;

[0014] A first Fourier transform lens and a first mask plate arranged on the rear focal plane of the first Fourier transform lens; the complementary Bessel light beam passes through the first Fourier transform lens to obtain a Fourier spectrum and passes through the first mask plate for filtering;

[0015] A second optical 4f system transmits the filtered Fourier spectrum to a two-photon microscopy imaging module.

[0016] Preferably, the two-photon microscopy imaging module includes: an XY point scanning device, a scanning lens, a sleeve lens, a microscope objective, a dichroic mirror, a filter, a focusing lens and a photomultiplier tube. The sample placed under the XY point scanning device excites a fluorescence signal through the filtered Fourier spectrum and forms a reverse reflected fluorescence signal. The filter and the focusing lens filter and focus the reflected fluorescence signal, and then the photomultiplier tube converts the fluorescence signal received by the photosensitive surface into a voltage signal and transmits it to the signal acquisition / imaging and synchronization control module.

[0017] Preferably, the spatial light modulator control module comprises: a controller for calculating and loading a phase pattern required on the spatial light modulator in the Bessel droplet modulation module, and the controller is electrically connected to the Bessel droplet modulation module.

[0018] Preferably, the horizontally polarized light beam passes through the first spatial light modulator to generate a first Bessel light droplet, and the phase pattern loaded by the first spatial light modulator is obtained by the spatial light modulator control module through calculation of two concentric rings and inverse Fourier transformation to generate two Bessel light beams with different NAs, which form standing waves with suppressed side lobes after interference, i.e., the first Bessel light droplet, and its axial light field distribution presents alternation of light and dark.

[0019] Preferably, the spatial light modulator control module selects the ratio of the inner and outer diameters corresponding to the best sidelobe suppression effect, and introduces a phase difference between the two concentric rings. , and the phase difference is obtained by inverse Fourier transform The phase pattern is loaded onto the first spatial light modulator to generate a first Bessel light droplet.

[0020] Preferably, the vertically polarized light beam passes through a second spatial light modulator to generate a second Bessel light droplet, and the phase pattern loaded by the second spatial light modulator is obtained by inverse Fourier transform of two concentric rings obtained by calculation by the spatial light modulator control module to generate two Bessel light beams with different NAs, which interfere to form a standing wave with suppressed side lobes, i.e., the second Bessel light droplet, and its axial light field distribution presents alternation of light and dark;

[0021] Preferably, the spatial light modulator control module selects two identical concentric rings to introduce a phase difference , and the phase difference is obtained by inverse Fourier transform The phase pattern is loaded onto the second spatial light modulator to generate a second Bessel light droplet.

[0022] Preferably, the excitation light source module includes: an ultrafast laser for generating ultrafast laser; a first optical 4f system for collimation and beam expansion; a first half-wave plate for adjusting the linear polarization direction of the laser; and a first polarization beam splitter for splitting the laser into a horizontally polarized beam and a vertically polarized beam.

[0023] Preferably, the XY point scanning device is a dual galvanometer galvanometer group or a resonant galvanometer combined with a galvanometer.

[0024] Compared with the prior art, the embodiments of the present application have the following beneficial effects:

[0025] The complementary Bessel droplet two-photon microscopic imaging system provided by the present invention generates two coaxial Bessel light beams with different NAs through the first spatial light modulator and the second spatial light modulator in the Bessel droplet modulation module and simultaneously introduces different phase differences, so that the phase difference Coaxial double Bessel beam interference forms Bessel light droplets with phase difference The coaxial double Bessel beam is offset in the axial light field distribution to obtain complementary Bessel light droplets, which are used to excite the two-photon fluorescence microscopy system to achieve fast, high-contrast and high-spatial-resolution volume imaging of biological tissues. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a control flow chart of a complementary Bessel light droplet two-photon microscopic imaging system provided by the present invention.

[0027] Figure 2 It is a structural schematic diagram of a complementary Bessel light droplet two-photon microscopic imaging system provided by the present invention.

[0028] Description of reference numerals:

[0029] 101. Excitation light source module; 1. Ultrafast laser; 2. First optical 4f system; 3. First half-wave plate; 4. First polarization beam splitter;

[0030] 102, Bessel light droplet modulation module; 5, first spatial light modulator; 6, second spatial light modulator; 7, second polarization beam splitter; 8, first Fourier transform lens; 9, first mask; 10, second optical 4f system;

[0031] 103. Two-photon microscopic imaging module; 11. XY point scanning device; 12. Scanning lens; 13. Tube lens; 14. Microscope objective lens; 16. Dichroic mirror; 17. Filter; 18. Focusing lens; 19. Photomultiplier tube;

[0032] 104. spatial light modulator control module; 20. controller;

[0033] 105. Signal acquisition / imaging and synchronization control module; 21. Multifunctional acquisition card and processor;

[0034] 15. Samples. DETAILED DESCRIPTION

[0035] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by technicians in the technical field of this application; the terms used in the specification of the application herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" and any variations thereof in the specification and claims of this application and the above-mentioned drawings are intended to cover non-exclusive inclusions. The terms "first", "second", etc. in the specification and claims of this application or the above-mentioned drawings are used to distinguish different objects, not to describe a specific order.

[0036] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0037] The embodiment of the present invention provides a complementary Bessel light droplet two-photon microscopy imaging system, such as Figure 1-Figure 2 As shown, the complementary Bessel light droplet two-photon microscopy imaging system comprises:

[0038] The excitation light source module 101 generates a horizontal polarization state light beam and a vertical polarization state light beam by polarization beam splitting;

[0039] Bessel light droplet modulation module 102; the Bessel light droplet modulation module 102 modulates the horizontal polarization state light beam into a phase difference The first Bessel light droplet is formed by the interference of the coaxial double Bessel light beams; at the same time, the vertical polarization state light beam is modulated into a phase difference The first Bessel light droplet and the second Bessel light droplet are combined to generate a Bessel light droplet with complementary axial light field distribution, generate Fourier spectra of the first Bessel light droplet and the second Bessel light droplet, and filter out stray light;

[0040] Two-photon microscopy imaging module 103; the complementary Bessel light droplets are focused to the sample 15 through the two-photon microscopy imaging module 103 to achieve point scanning, and the two-photon microscopy imaging module 103 collects the backscattered fluorescence signal generated by the sample 15 after two-photon excitation and converts it into a voltage signal;

[0041] A spatial light modulator control module 104; the spatial light modulator control module 104 is electrically connected to the Bessel light droplet modulation module 102, and calculates and loads a phase pattern loaded on the spatial light modulator in the Bessel light droplet modulation module 102;

[0042] Signal acquisition / imaging and synchronization control module 105: The signal acquisition / imaging and synchronization control module 105 performs synchronization control on the output and acquisition of the fluorescence signal, and reconstructs a two-photon intensity map of the obtained voltage signal;

[0043] In this embodiment, the Bessel light droplet modulation module 102 includes:

[0044] A first spatial light modulator 5 and a second spatial light modulator 6; the horizontally polarized light beam passes through the first spatial light modulator 5 to generate a first Bessel light droplet, and the vertically polarized light beam passes through the second spatial light modulator 6 to generate a second Bessel light droplet;

[0045] A second polarization beam splitter 7, wherein the first Bessel light droplet and the second Bessel light droplet in different polarization states are combined through the second polarization beam splitter 7 to obtain a Bessel light beam with uniform axial light field distribution and suppressed side lobes, that is, complementary Bessel light droplets;

[0046] A first Fourier transform lens 8 and a first mask plate 9 arranged on the rear focal plane of the first Fourier transform lens 8; the complementary Bessel light beam passes through the first Fourier transform lens 8 to obtain a Fourier spectrum and passes through the first mask plate 9 for filtering;

[0047] A second optical 4f system 10, wherein the second optical 4f system 10 transmits the filtered Fourier spectrum to a two-photon microscopic imaging module 103;

[0048] In this embodiment, the first spatial light modulator 5 and the second spatial light modulator 6 adopt pure phase spatial light modulators in the prior art structure. The grayscale phase image loaded by the spatial light modulator control module 104 will apply different voltages to the liquid crystal molecules according to different grayscale levels, thereby changing the refractive index of the liquid crystal molecules to change the optical path, thereby achieving the purpose of modulating the light field.

[0049] The two-photon microscopic imaging module 103 includes: an XY point scanning device 11, a scanning lens 12, a sleeve lens 13, a microscope objective lens 14, a dichroic mirror 16, a filter 17, a focusing lens 18 and a photomultiplier tube 19. The sample 15 placed below the XY point scanning device 11 excites a fluorescence signal through the filtered Fourier spectrum and forms a reverse reflected fluorescence signal. The filter 17 and the focusing lens 18 filter and focus the reflected fluorescence signal, and then the photomultiplier tube 19 converts the fluorescence signal received by the photosensitive surface into a voltage signal and transmits it to the signal acquisition / imaging and synchronization control module 105. The two-photon microscopic imaging module 103 adopts existing technical means;

[0050] The spatial light modulator control module 104 includes: a controller 20, which is used to calculate and load a phase pattern to be loaded on the spatial light modulator in the Bessel droplet modulation module 102;

[0051] The signal acquisition / imaging and synchronization control module 105 includes a multifunctional acquisition card and a processor 21; the multifunctional acquisition card and the processor 21 control the motion control of the stage and the motion of the objective lens 14 in the two-photon microscopic imaging module, and by controlling the X and Y scanning galvanometers 11 in the two-photon microscopic imaging module 103, the multifunctional acquisition card and the processor 21 collect and convert the fluorescence signal of the photomultiplier tube 19 in the two-photon microscopic imaging module 103, and simultaneously realize the synchronization control of the above-mentioned signal output and acquisition; the voltage signal converted by the photomultiplier tube 19 is reconstructed into a two-photon intensity map; the multifunctional acquisition card and the processor 21 use existing technical means to collect and output signals;

[0052] As a preferred implementation in this embodiment, the horizontal polarization state light beam passes through the first spatial light modulator 5 to generate a first Bessel light droplet. The phase pattern loaded by the first spatial light modulator 5 is the spatial light modulator control module 104 which calculates the phase difference to be The two concentric rings are obtained by inverse Fourier transformation to generate two Bessel light beams with different NAs, which interfere to form standing waves with suppressed side lobes, i.e., the first Bessel light droplet, whose axial light field distribution presents alternating light and dark; the vertically polarized light beam passes through the second spatial light modulator 6 to generate a second Bessel light droplet, and the phase pattern loaded by the second spatial light modulator 6 is the spatial light modulator control module 104, which calculates the phase difference to be The two concentric rings are obtained by inverse Fourier transformation to generate two Bessel light beams with different NAs, which interfere to form standing waves with suppressed side lobes, i.e., the second Bessel light droplet, whose axial light field distribution presents alternating light and dark;

[0053] Characteristics of Bessel beams and their Fourier spectrum, i.e. the radius of the ring Closely related, the central spot radius can be expressed as:

[0054]

[0055] The diffraction-free distance of a Bessel beam can be expressed as:

[0056]

[0057] The effective numerical aperture of a Bessel beam can be expressed as:

[0058]

[0059] in, is the laser wavelength, is the focal length of the Fourier transform lens, is the radius of the beam incident on the spatial light modulator, is the effective focal length of the objective lens.

[0060] The characteristics of Bessel light droplets and the Fourier spectrum, that is, the ratio of the inner diameter to the outer diameter of the concentric rings Closely related, The value of is between 0 and 1. When , it behaves as a standard Bessel beam, that is, there is no sidelobe suppression effect; the ratio of the inner and outer diameters is Depends on the corresponding Bessel light drop sidelobe energy ratio;

[0061] The spatial light modulator control module 104 selects the ratio of the inner and outer diameters corresponding to the best sidelobe suppression effect. , introducing a phase difference between the two concentric rings , and the phase difference is obtained by inverse Fourier transform The phase pattern is loaded onto the first spatial light modulator 5 to generate a first Bessel light droplet; a phase difference is introduced between the same two concentric rings. , and the phase difference is obtained by inverse Fourier transform The phase pattern is loaded onto the second spatial light modulator 6 to generate a second Bessel light droplet;

[0062] As a preferred implementation in this embodiment, the excitation light source module 101 includes: an ultrafast laser 1, used to generate ultrafast laser; a first optical 4f system 2, used to collimate and expand the beam; a first half-wave plate 3, used to adjust the linear polarization direction of the laser; a first polarization beam splitter 4, used to split the laser into a horizontal polarization state beam and a vertical polarization state beam;

[0063] In this embodiment, the ultrafast laser 1 may be a picosecond laser or a femtosecond laser, which essentially outputs ultrashort pulse lasers with extremely high instantaneous power;

[0064] As a preferred implementation in this embodiment, the XY point scanning device 11 can be a dual-galvanometer galvanometer group or a resonant galvanometer with a galvanometer; the scanning lens 12 and the sleeve lens 13 are used to expand the laser beam so that it fills the entrance pupil surface of the objective lens 14 and produces a fixed-size light spot in the entire field of view on the plane of the sample 15; the microscope objective lens 14 is used to focus the excitation beam; the dichroic mirror 16 is used to transmit the excitation light and reflect the backscattered fluorescence signal; the filter 17 is used to further filter out other stray light except the fluorescence signal; the focusing lens 18 is used to focus the divergent fluorescence signal onto the photosensitive surface of the photomultiplier tube 19; the photomultiplier tube 19 is used to convert the fluorescence signal received by the photosensitive surface into a voltage signal;

[0065] It should be noted that, for the above-mentioned embodiments, for the sake of simplicity, they are all described as a series of action combinations, but those skilled in the art should know that the present invention is not limited by the described order of actions, because according to the present invention, some steps may be performed in other orders or simultaneously. Secondly, those skilled in the art should also know that the embodiments described in the specification are all preferred embodiments, and the actions and modules involved are not necessarily required by the present invention.

[0066] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the scope of protection of the invention. Obviously, the described embodiments are only some embodiments of the present invention, rather than all embodiments. Based on these embodiments, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in this field can still combine, add, delete or make other adjustments to the features in the various embodiments of the present invention according to the circumstances without conflict, without making creative work, so as to obtain different other technical solutions that do not deviate from the concept of the present invention in essence, and these technical solutions also belong to the scope of protection of the present invention.

Claims

1. A complementary Bessel droplet two-photon microscopy imaging system, characterized in that: include: Excitation light source module; The excitation light source module generates a horizontal polarization state light beam and a vertical polarization state light beam by using polarization beam splitting; Bessel light droplet modulation module, the Bessel light droplet modulation module modulates the horizontal polarization state light beam into a phase difference The first Bessel light droplet is formed by the interference of the coaxial double Bessel light beams; at the same time, the vertical polarization state light beam is modulated into a phase difference The first Bessel light droplet and the second Bessel light droplet are combined to form a complementary Bessel light droplet, and the Fourier spectrum of the first Bessel light droplet and the second Bessel light droplet is generated and the stray light thereof is filtered out; A two-photon microscopic imaging module, wherein the complementary Bessel light droplets are focused on the sample to be measured through the two-photon microscopic imaging module to realize point scanning, and the two-photon microscopic imaging module collects the backscattered fluorescence signal generated by the sample after two-photon excitation and converts it into a voltage signal; A spatial light modulator control module, the spatial light modulator control module is electrically connected to the Bessel light droplet modulation module, and calculates and loads a phase pattern required on the Bessel light droplet modulation module; The signal acquisition / imaging and synchronization control module controls the synchronization of the output and acquisition of the fluorescence signal, and reconstructs a two-photon intensity map of the obtained voltage signal.

2. A complementary Bessel droplet two-photon microscopy imaging system as claimed in claim 1, characterized in that: The Bessel light droplet modulation module comprises: A first spatial light modulator and a second spatial light modulator; the horizontally polarized light beam passes through the first spatial light modulator to generate a first Bessel light droplet, and the vertically polarized light beam passes through the second spatial light modulator to generate a second Bessel light droplet; A second polarization beam splitter, wherein the first Bessel light droplet and the second Bessel light droplet in different polarization states are combined through the second polarization beam splitter to obtain a Bessel light beam with uniform axial light field distribution and suppressed side lobes, that is, complementary Bessel light droplets; A first Fourier transform lens and a first mask plate arranged on the rear focal plane of the first Fourier transform lens; the complementary Bessel light beam passes through the first Fourier transform lens to obtain a Fourier spectrum and passes through the first mask plate for filtering; A second optical 4f system transmits the filtered Fourier spectrum to a two-photon microscopy imaging module.

3. A complementary Bessel droplet two-photon microscopy imaging system as claimed in claim 2, characterized in that: The two-photon microscopy imaging module includes: an XY point scanning device, a scanning lens, a sleeve lens, a microscope objective, a dichroic mirror, a filter, a focusing lens and a photomultiplier tube. The sample placed under the XY point scanning device excites a fluorescence signal through the filtered Fourier spectrum and forms a reverse reflected fluorescence signal. The filter and the focusing lens filter and focus the reflected fluorescence signal, and then the photomultiplier tube converts the fluorescence signal received by the photosensitive surface into a voltage signal and transmits it to the signal acquisition / imaging and synchronization control module.

4. A complementary Bessel droplet two-photon microscopy imaging system as claimed in claim 3, characterized in that: The spatial light modulator control module includes: a controller for calculating and loading a phase pattern required on the spatial light modulator in the Bessel light droplet modulation module, and the controller is electrically connected to the Bessel light droplet modulation module.

5. A complementary Bessel droplet two-photon microscopy imaging system as claimed in claim 4, characterized in that: The horizontally polarized light beam passes through the first spatial light modulator to generate a first Bessel light droplet. The phase pattern loaded by the first spatial light modulator is obtained by inverse Fourier transform of two concentric rings calculated by the spatial light modulator control module to generate two Bessel light beams with different NAs. After interference, a standing wave with suppressed side lobes is formed, i.e., the first Bessel light droplet, and its axial light field distribution presents alternation of light and dark.

6. A complementary Bessel droplet two-photon microscopy imaging system as claimed in claim 5, characterized in that: The spatial light modulator control module selects the ratio of the inner and outer diameters corresponding to the best sidelobe suppression effect, and introduces a phase difference between the two concentric rings. , and the phase difference is obtained by inverse Fourier transform The phase pattern is loaded onto the first spatial light modulator to generate a first Bessel light droplet.

7. A complementary Bessel droplet two-photon microscopy imaging system as claimed in claim 6, characterized in that: The vertically polarized light beam passes through the second spatial light modulator to generate a second Bessel light droplet. The phase pattern loaded by the second spatial light modulator is obtained by inverse Fourier transform of two concentric rings calculated by the spatial light modulator control module to generate two Bessel light beams with different NAs. After interference, standing waves with suppressed side lobes are formed, namely the second Bessel light droplets, and their axial light field distribution presents alternation of light and dark.

8. A complementary Bessel droplet two-photon microscopy imaging system as claimed in claim 7, characterized in that: The spatial light modulator control module selects two identical concentric rings to introduce a phase difference , and the phase difference is obtained by inverse Fourier transform The phase pattern is loaded onto the second spatial light modulator to generate a second Bessel light droplet.

9. A complementary Bessel droplet two-photon microscopy imaging system as claimed in claim 8, characterized in that: The excitation light source module includes: an ultrafast laser for generating ultrafast laser; a first optical 4f system for collimation and beam expansion; a first half-wave plate for adjusting the linear polarization direction of the laser; and a first polarization beam splitter for splitting the laser into a horizontally polarized beam and a vertically polarized beam.

10. A complementary Bessel droplet two-photon microscopy imaging system as claimed in claim 9, characterized in that: The XY point scanning device is a dual galvanometer galvanometer group or a resonant galvanometer with a galvanometer.

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