An all-optical high-speed multi-photon scanning imaging device

Abstract

The present invention belongs to the technical field of scanning devices, and specifically relates to an all-optical high-speed multi-photon scanning imaging device, including a laser, a relay, a scanning mechanism and an imaging mechanism; further including a beam expander and a circular beam splitting mechanism; the circular beam splitting mechanism includes a beam splitter, a first reflector and a second reflector; the transmittance of the beam splitter is m; the angle between the beam splitter and the incident light axis of the laser is 45+a degrees; the first reflector is an L-shaped reflector with an angle of 90 degrees, the two reflecting surfaces of the first reflector form an angle of 90 degrees, and the angles along the long lines of the two reflecting surfaces with the incident light axis of the laser are 45 degrees respectively; the reflecting surface of the second reflector faces the beam splitter, and the angle between the second reflector and the incident light axis of the laser is 45 degrees; the beam expander is used to expand the diameter of the beam emitted by the laser and send it to the beam splitter; the relay is used to receive the transmitted light of the beam splitter and send it to the scanning mechanism. The present application realizes the imaging advantage of point scanning on scattering media and ensures the imaging depth.

Description

Technical Field

[0001] The present invention belongs to the technical field of scanning devices, and in particular relates to an all-optical high-speed multi-photon scanning imaging device. Background Art

[0002] In order to observe rapidly changing neural activities, especially to directly image voltage-sensitive dyes, multiphoton fluorescence microscopy requires an imaging rate of up to thousands of frames, which cannot be achieved by mechanical galvanometers. One of the solutions to achieve high-speed scanning is the so-called parallelization, which divides the laser beam into several small beamlets through a microlens array. All small beamlets scan the sample at the same time and are detected simultaneously by multiple photodetectors or a CCD / CMOS camera. There are some problems with this idea. The diameter of the small beamlet separated from the same laser beam by the wavefront splitting method is too small to fill the exit pupil of the objective lens and meet the requirements of the numerical aperture of the objective lens (resulting in a lower numerical aperture and poorer resolution); multiple detectors or a CCD / CMOS camera simultaneously detect similar full-field imaging, which cannot distinguish the scattered light of biological samples, resulting in limited imaging depth.

[0003] Later, FACED technology emerged. It not only uses the wavefront splitting method to divide the laser beam into several small beams according to different angles after focusing, but also time-stretches several small beams so that small beams at different angles arrive at different positions of the focal plane of the objective lens in sequence at specific time intervals, thereby maintaining the imaging advantage of point scanning for scattering media, and can use a single photomultiplier tube PMT for detection. By using a femtosecond laser with a repetition rate of 1MHz, an imaging speed of 1M lines per second is achieved. Summary of the invention

[0004] The purpose of the present invention is to provide an all-optical high-speed multi-photon scanning imaging device, which realizes the imaging advantages of point scanning on scattering media and ensures imaging depth by adopting a technology different from the FACED technology.

[0005] The basic scheme provided by the present invention is:

[0006] An all-optical high-speed multi-photon scanning imaging device, comprising a laser, a relay unit, a scanning mechanism and an imaging mechanism;

[0007] It also includes a beam expander and a circular beam splitting mechanism; the circular beam splitting mechanism includes a beam splitter, a first reflector and a second reflector; the transmittance of the beam splitter is m; the angle between the beam splitter and the incident light axis of the laser is 45+a degrees; the first reflector is an L-shaped reflector with an angle of 90 degrees, the two reflective surfaces of the first reflector form an angle of 90 degrees, and the angles between the two reflective surfaces and the incident light axis of the laser are 45 degrees along the long lines; the reflective surface of the second reflector faces the beam splitter, and the angle between the second reflector and the incident light axis of the laser is 45 degrees;

[0008] The beam expander is used to expand the diameter of the beam emitted by the laser and send it to the beam splitter; the beam splitter obtains the transmitted light and the reflected light according to the received beam, and sends the reflected light to one reflective surface of the first reflector, and sends the transmitted light to the relay unit; one reflective surface of the first reflector receives the reflected light and reflects it to the other reflective surface, and the other reflective surface receives the reflected light and reflects it to the second reflector; the second reflector receives the reflected light and reflects it to the beam splitter; the beam splitter obtains the transmitted light and the reflected light of the next level according to the received reflected light, and the above process is repeated;

[0009] The relay unit is used to receive the transmitted light of the beam splitter and send it to the scanning mechanism; the scanning mechanism is used to scan the light beam sent by the relay unit and send it to the imaging mechanism; the imaging mechanism is used to perform imaging scanning according to the received light beam.

[0010] Basic solution working principle and beneficial effects:

[0011] The laser beam output is directed to the beam splitter after its diameter is expanded by a beam expander; by expanding the beam diameter by a beam expander, it can be ensured that the subsequently generated transmitted light fills the exit pupil of the objective lens and meets the requirements of the numerical aperture of the objective lens.

[0012] After receiving the beam sheet sent by the beam expander, the beam splitter splits the light into the first penetrating light and the first reflected light; after the first reflected light is reflected on the first reflector, it is reflected by the two reflective surfaces of the first reflector and sent to the second reflector, and then the second reflector reflects the first reflected light to the beam splitter; after receiving the first reflected light, the beam splitter splits it into the second penetrating light and the second reflected light. The above operation is repeated.

[0013] In the above process, each time the beam splitter generates a reflected light, the reflected light will be reflected by the two reflective surfaces of the first reflector and sent to the second reflector, and then the second reflector will reflect the reflected light to the beam splitter, and the beam splitter will generate the next level of penetrating light and reflected light. Combining the installation position and installation angle of the beam splitter, the first reflector, and the second reflector, it can be known that the reflected light will pass through a 2L optical path from being generated by the beam splitter to returning to the beam splitter, where L is the distance between the intersection of the two reflective surfaces of the first reflector and the incident optical axis of the laser. Therefore, there will be a time interval of 2L / c between any two adjacent levels of penetrating light, where c is the speed of light in a vacuum. In addition, when the reflected light reaches the beam splitter, there is an angle of 2a between it and the reflected light of the previous level. Therefore, there will also be an angle of 2a between any two adjacent levels of penetrating light. In summary, there will be a time interval of 2L / c and an angle of 2a between any two adjacent levels of penetrating light.

[0014] After the penetrating light is generated, it passes through the relay unit and reaches the scanning unit. After the scanning unit scans, the transmitted light reaches the imaging mechanism for imaging scanning. Since there is a time interval of 2L / c and an angle of 2a between any two adjacent levels of penetrating light, each level of penetrating light will successively reach different positions of the focal plane of the objective lens of the imaging mechanism at different angles and specific time intervals.

[0015] In this way, the imaging advantage of point scanning for scattering media can be realized and the imaging depth can be guaranteed.

[0016] Furthermore, m is greater than or equal to 0.1% and less than or equal to 10%.

[0017] It is possible to ensure that a sufficient amount of transmitted light for scanning is generated, while ensuring the quality of the transmitted light used for scanning.

[0018] Furthermore, m is 1.25%.

[0019] Such a transmittance can well balance the quantity and quality of the transmitted light used for scanning.

[0020] Furthermore, a is greater than or equal to 0.01 and less than or equal to 0.1.

[0021] The angle between two adjacent levels of penetrating light can be reasonably controlled, thereby controlling the position of the light spot in the focal plane of the objective lens.

[0022] Furthermore, a is 0.08.

[0023] It can make the light spots have a reasonable position interval on the focal plane of the objective lens.

[0024] Furthermore, it also includes a precision moving stage, the moving direction of which is 90 degrees to the incident optical axis of the laser; and the first reflecting mirror is fixed on the precision moving stage.

[0025] According to actual needs, the distance between the first reflector and the incident light axis of the laser can be adjusted by a precision moving stage, thereby adjusting the interval time between two adjacent levels of penetrating light.

[0026] Furthermore, it also includes a precision rotating stage, on which the reflector is mounted.

[0027] According to actual needs, the angle between the beam splitter and the incident light axis of the laser (ie, the value of a) can be adjusted by a precision rotating stage, thereby controlling the angle between two adjacent levels of penetrating light.

[0028] Furthermore, the scanning mechanism includes two scanning galvanometers arranged in sequence along the optical path direction. The first scanning galvanometer is used to perform X-axis movement scanning on the light beam and then send it to the second scanning galvanometer. The second scanning galvanometer is used to perform Y-axis movement scanning on the light beam and then send it to the imaging mechanism.

[0029] Able to select scanning area quickly and accurately over a large range.

[0030] Furthermore, the relay part includes two groups of relay lenses, the beam splitter is located at a focus of the first group of relay lenses, the other focus of the first group of relay lenses coincides with a focus of the second group of relay lenses, and the other focus of the second group of relay lenses is located on the scanning surface of the first scanning galvanometer.

[0031] The two sets of relay lenses can stably play the role of imaging relay.

[0032] Compared with the existing technology, one of the most creative aspects of this scheme is that it uses the amplitude division method to split the laser pulse through a cyclic beam splitting mechanism. The energy difference between the small pulses formed after the laser pulse is split by the amplitude division method is very small, so that the intensity distribution of the final scanning light spot sequence is very uniform, which is beneficial to improving the imaging depth and contrast.

[0033] In the prior art, the commonly used encoding by spectrum (wavelength) cannot be used for multiphoton imaging because it completely separates the ultrafast pulses according to the spectrum, broadens the ultrafast pulses, and directly affects the imaging depth and contrast. Another less commonly used encoding method according to spatial position is the aforementioned wavefront splitting method. Since the output beam of the laser is a Gaussian beam, strong in the center and weak at the edge, the intensity of the scanning light spot sequence generated by the wavefront splitting method is also Gaussian distributed, which is very uneven, thus directly leading to uneven imaging and large differences in brightness.

[0034] Therefore, by using this solution, not only can the cost be controlled, but also the uniformity of the scanning light spot sequence can be improved, resulting in a better imaging effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 This is a schematic diagram of the optical path of Embodiment 1 of the present invention;

[0036] Figure 2 Schematic diagram of the optical path of the circular beam splitting mechanism in the first embodiment of the present invention;

[0037] Figure 3 This is a scanning light spot intensity distribution diagram in the first embodiment of the present invention. DETAILED DESCRIPTION

[0038] The following is a further detailed description through specific implementation methods:

[0039] The reference numerals in the drawings of the specification include: laser 1, beam expander 2, circular beam splitting mechanism 3, beam splitter 31, first reflector 32, second reflector 32, relay lens 4, scanning mechanism 5, imaging mechanism 6.

[0040] Embodiment 1

[0041] like Figure 1 , Figure 2 As shown, an all-optical high-speed multi-photon scanning imaging device includes a laser 1, a beam expander 2, a cyclic beam splitting mechanism 3, a relay unit, a scanning mechanism 5 and an imaging mechanism 6.

[0042] The laser 1 is used to output laser pulses; the beam expander 2 is used to expand the laser output by the laser 1.

[0043] The circular beam splitting mechanism 3 includes a beam splitter 31 , a first reflecting mirror 32 and a second reflecting mirror 32 .

[0044] The angle between the beam splitter 31 and the incident light axis of the laser 1 is 45+a degrees, where a is greater than or equal to 0.01 and less than or equal to 0.1. In this embodiment, a is 0.08. The first reflector 32 is an L-shaped reflector with an angle of 90 degrees. The two reflective surfaces of the first reflector 32 form an angle of 90 degrees, and the angles along the long lines of the two reflective surfaces with the incident light axis of the laser 1 are 45 degrees respectively; in this embodiment, the lengths of the two reflective surfaces of the first reflector 32 are equal. The reflective surface of the second reflector 32 faces the beam splitter 31, and the angle between the second reflector 32 and the incident light axis of the laser 1 is 45 degrees.

[0045] The beam expander 2 is used to expand the diameter of the light beam emitted by the laser 1 and send it to the beam splitter 31; the beam splitter 31 obtains the transmitted light and the reflected light according to the received light beam, and sends the reflected light to a reflecting surface of the first reflecting mirror 32, and sends the transmitted light to the relay part; one reflecting surface of the first reflecting mirror 32 receives the reflected light and reflects it to the other reflecting surface, and the other reflecting surface receives the reflected light and reflects it to the second reflecting mirror 32; the second reflecting mirror 32 receives the reflected light and reflects it to the beam splitter 31; the beam splitter 31 obtains the next level of transmitted light and reflected light according to the received reflected light, and the above process is repeated.

[0046] Among them, the transmittance of the beam splitter 31 is m, m is greater than or equal to 0.1% and less than or equal to 10%. In this embodiment, m is 1.25%. Such a transmittance can ensure the generation of a sufficient amount of transmitted light for scanning, while ensuring the quality of the transmitted light used for scanning. Considering that the energy of a single pulse output by the laser 1 is repeatedly extracted to form a small pulse (generated transmitted light) that can still meet the requirements of multi-photon imaging, if the number of points (the number of transmitted light used for scanning) is too low, it will cause energy waste; on the other hand, if the number of points (the number of transmitted light used for scanning) is too high, it will cause the average power of the laser 1 to be too high, and the repetition frequency of the laser 1 is too low, which will reduce the scanning speed. When m is 1.25%, the beam splitter 31 can generate about 80 times of usable transmitted light, and the remaining light is discarded because of its low energy, fast speed and uncontrollable. In this embodiment, the data acquisition card can be directly controlled not to collect the signal of this part of the remaining light, and this part of the light will not be reflected in the image. Such a transmittance setting and the 80-cycle segmentation of the laser pulse are both of positive significance. Because the energy of each pulse of the currently commonly used low repetition frequency pulse laser 1 is about 80 times that of the 80MHz laser 1 for imaging, the pulse is divided into 80 parts in this embodiment. Because the energy of each pulse is much less than that of the previous one, such a transmittance can ensure that the energy of the 80th pulse is still sufficient to ensure the imaging depth. It can take into account the energy utilization rate and scanning speed of the laser 1.

[0047] In this embodiment, laser 1 uses Monaco 1035-40-40, with a repetition frequency of 1MHz, a pulse width of 315fs, and an average power of 35W. It is used as a pump source to construct an optical parametric amplifier Opera-F, which generates a pulse laser with a wavelength of 920nm, a repetition frequency of 1MHz, and an average power of 2W. In the prior art, most of the lasers used for neural activity scanning use the Insight X3 titanium sapphire femtosecond oscillator, which generates laser pulses with a wavelength of 920nm, a repetition frequency of 80MHz, and an average power of 2W. Through the 80 cuts in this embodiment, the pulse laser generated by laser 1 can be cut so that the energy of each small pulse is not lower than the imaging scanning energy in the prior art, which can ensure the imaging depth and enable scanning imaging.

[0048] The relay unit is used to receive the transmitted light of the beam splitter 31 and send it to the scanning mechanism 5. The scanning mechanism 5 includes two scanning galvanometers, the first scanning galvanometer is used to move and scan the light beam along the X axis and then send it to the second scanning galvanometer, and the second scanning galvanometer is used to move and scan the light beam along the Y axis and then send it to the imaging mechanism 6. The relay unit includes two groups of relay lenses 4, the beam splitter is located at a focus of the first group of relay lenses 4, the other focus of the first group of relay lenses 4 coincides with a focus of the second group of relay lenses 4, and the other focus of the second group of relay lenses 4 is located on the scanning surface of the first scanning galvanometer. In this embodiment, the two groups of relay lenses 4 are lenses with focal lengths of 600 mm and 300 mm, respectively, and the two groups of relay lenses 4 can be double-cemented lenses or Plossl eyepieces.

[0049] The scanning mechanism 5 is used to scan the transmitted light sent by the relay unit and send it to the imaging mechanism 6. The imaging mechanism 6 is used to perform imaging scanning according to the received light beam. The imaging mechanism 6 can adopt an existing conventional mechanism. In this embodiment, the imaging mechanism 6 includes a scanning lens, a sleeve lens, an objective lens, a dichroic mirror, a filter, a focusing lens, a photomultiplier tube and a high-speed DAQ acquisition card.

[0050] The specific implementation process is as follows:

[0051] Different from the wavefront division method used in the prior art, the present application adopts the amplitude division method; the laser beam outputted by the beam expands its diameter through the beam expander 2, becomes a beam with a diameter of D and is emitted to the beam splitter 31; the beam splitter 31 receives the beam sheet sent by the beam expander 2 and splits it into the first penetrating light and the first reflected light. The first penetrating light is photographed and then scanned by the scanning unit after being relayed by the lens.

[0052] After the first reflected light is reflected on the first reflector 32, it is reflected by the two reflective surfaces of the first reflector 32 and sent to the second reflector 32, and then the second reflector 32 reflects the first reflected light to the beam splitter 31; after receiving the first reflected light, the beam splitter 31 splits it into the second transmitted light and the second reflected light. The above operation is repeated.

[0053] In the above process, each time the beam splitter 31 generates a reflected light, the reflected light will be reflected by the two reflecting surfaces of the first reflector 32 and sent to the second reflector 32, and then the second reflector 32 will reflect the reflected light to the beam splitter 31, and the beam splitter 31 will generate the next level of penetrating light and reflected light. Combining the installation position and installation angle of the beam splitter 31, the first reflector 32, and the second reflector 32, it can be known that the reflected light will pass through a 2L optical path from being generated by the beam splitter 31 to returning to the beam splitter 31, where L is the distance between the intersection of the two reflecting surfaces of the first reflector 32 and the incident light axis of the laser 1. Therefore, there will be a time interval of 2L / c between any two adjacent levels of penetrating light, where c is the speed of light in a vacuum. Moreover, when the reflected light reaches the beam splitter 31, there is an angle of 2a between it and the previous level of reflected light. Therefore, there will also be an angle of 2a between any two adjacent levels of penetrating light. In summary, there will be a time interval of 2L / c and an angle of 2a between any two adjacent levels of penetrating light.

[0054] After the penetrating light is generated, it reaches the scanning part after passing through the relay part. After the scanning part scans the transmitted light, the transmitted light passes through the sleeve lens and is focused by the objective lens. The fluorescence emitted by the sample is collected and enters the photomultiplier tube through the dichroic mirror, the filter, and the focusing lens, and is digitized by the high-speed DAQ acquisition card. Since there is a time interval of 2L / c and an angle of 2a between any two adjacent levels of the transmitted light, the transmitted light of each level will successively arrive at different positions of the focal plane of the objective lens at different angles and specific time intervals. Specifically, in this embodiment, the time interval of the light spot after the light beam is focused by the objective lens is 2L / c, and the spatial interval of the light spot in the focal plane of the objective lens is about f*tan(2a), where f is the focal length of the objective lens. Of course, in order to adapt to different objective lenses and imaging mechanisms 6, the total angle 160a and the laser beam diameter D after beam expansion can be calculated separately, and then the beam splitter and the beam expander 2 are adjusted and set to meet actual needs.

[0055] As a calculation example, the pulse width of a typical ultrafast laser pulse is about 100fs, and the time interval of the light spots is 2L / c. For example, when L=300mm, the time interval is 2ns. If a laser 1 with a repetition frequency of 1MHz is used, the interval between each pulse is 1us. In this way, there will be a light spot that scans along the X axis at an interval of 2ns, a group of 80 light spots, which takes about 160ns, and then idles for 840ns before the next group of 80 light spots appears.

[0056] like Figure 3 As shown, in this embodiment, the amplitude division method is used to divide the laser pulse, which can effectively ensure the uniformity of the distribution of the formed scanning light spot sequence. Among them, the highest and lowest energies of the entire sequence are only 2.5 times different, which is much more uniform than the distribution of the scanning light spot sequence in the prior art. And because of the specific setting of the circular beam splitting mechanism 3 in this embodiment, the energy of the first light spot corresponding to the first pulse formed by the division is the strongest, and the energy of the pulses formed by the division is reduced one by one, so that the formed scanning light spot sequence can form a curve that gradually and slowly tilts downward, and the curve formed by the entire scanning light spot sequence is very smooth and has a very high uniformity.

[0057] In the prior art, the commonly used SE (Spectrally Encoded), encoding by spectrum, or encoding by wavelength, is to use a grating to separate the incoming ultrafast pulses by spectrum, because some wavelengths arrive first and some arrive later. Obviously, this method cannot be used for multi-photon imaging. Because multi-photon imaging is very fast, in order to maintain ultrafast pulses, all spectra must propagate together. In fact, the propagation speed of different wavelengths is fast and slow, which will cause pulse broadening, reduce peak energy, and affect imaging depth and contrast. What's more, the existing technology cannot achieve high-speed multi-photon scanning imaging by completely separating different wavelengths.

[0058] In the prior art, another less commonly used method is encoding according to spatial position, that is, dividing according to the spatial position of the laser pulse or laser beam, which is the split wavefront method mentioned above. Since the output beams of the laser 1 are all Gaussian beams, the central energy is strong or the amplitude is large, and the edge energy is weak or the amplitude is small; the beam becomes multiple small beams after being split, so when the small beams continue to transmit, the light spot of the small beam corresponding to the edge of the beam before the original split wavefront must arrive at the focal plane of the objective lens first, and its energy must be weak and its amplitude must be small. Then, the light spot of the small beam corresponding to the middle position of the beam before the original split wavefront must arrive at the focal plane of the objective lens at the intermediate time point, which is located at the top of the Gaussian curve, has the strongest energy and the largest amplitude. The light spot of the small beam corresponding to the edge of the beam before the original split wavefront must arrive at the focal plane of the objective lens last, and its energy must be weak and its amplitude must be small. In short, when the laser beam is split according to the wavefront division method, the intensity distribution of the scanning light spot sequence generated is also Gaussian distribution, which is very uneven. On the same image, the central part has good contrast and high signal-to-noise ratio, while the parts on the edges of both sides have poor contrast and low signal-to-noise ratio, which directly affects the imaging effect. Compared with the Gaussian distribution curve formed by the scanning light spot intensity sequence according to the wavefront division method, the uniformity of this embodiment has obvious advantages.

[0059] Embodiment 2

[0060] Different from the first embodiment, this embodiment further includes a precision moving stage, the moving direction of which is 90 degrees to the incident light axis of the laser 1, and the first reflector 32 is mounted on the precision moving stage. With such a setting, the distance between the first reflector 32 and the incident light axis of the laser 1 (i.e., the value of L) can be adjusted by the precision moving stage according to actual needs, thereby adjusting the interval time between two adjacent levels of penetrating light.

[0061] Embodiment 3

[0062] Different from the first embodiment, this embodiment further includes a precision rotating stage, on which the reflector is mounted. With this arrangement, the angle between the beam splitter 31 and the incident light axis of the laser 1 (i.e., the value of a) can be adjusted by the precision rotating stage according to actual needs, thereby controlling the angle between two adjacent levels of penetrating light.

[0063] The above is only an embodiment of the present invention. The common sense such as the known specific structure and characteristics in the scheme is not described in detail here. The ordinary technicians in the relevant field know all the common technical knowledge in the technical field of the invention before the application date or priority date, can obtain all the existing technologies in the field, and have the ability to apply the conventional experimental means before that date. The ordinary technicians in the relevant field can improve and implement this scheme in combination with their own abilities under the enlightenment given by this application. Some typical known structures or known methods should not become obstacles for ordinary technicians in the relevant field to implement this application. It should be pointed out that for those skilled in the art, without departing from the structure of the present invention, several deformations and improvements can be made, which should also be regarded as the protection scope of the present invention, which will not affect the effect of the implementation of the present invention and the practicality of the patent. The protection scope required by this application shall be based on the content of its claims, and the specific implementation methods and other records in the specification can be used to interpret the content of the claims.

Claims

1. An all-optical high-speed multi-photon scanning imaging device, comprising a laser, a relay unit, a scanning mechanism and an imaging mechanism; Features: It also includes a beam expander and a circular beam splitting mechanism; the circular beam splitting mechanism includes a beam splitter, a first reflector and a second reflector; the transmittance of the beam splitter is m; the angle between the beam splitter and the incident light axis of the laser is 45+a degrees; the first reflector is an L-shaped reflector with an angle of 90 degrees, the two reflective surfaces of the first reflector form an angle of 90 degrees, and the angles between the two reflective surfaces and the incident light axis of the laser are 45 degrees along the long lines; the reflective surface of the second reflector faces the beam splitter, and the angle between the second reflector and the incident light axis of the laser is 45 degrees; The beam expander is used to expand the diameter of the beam emitted by the laser and send it to the beam splitter; the beam splitter obtains the transmitted light and the reflected light according to the received beam, and sends the reflected light to one reflective surface of the first reflector, and sends the transmitted light to the relay unit; one reflective surface of the first reflector receives the reflected light and then reflects it to the other reflective surface, and the other reflective surface receives the reflected light and then reflects it to the second reflector; the second reflector receives the reflected light and then reflects it to the beam splitter; the beam splitter obtains the transmitted light and the reflected light of the next level according to the received reflected light, and the above process is repeated; The relay unit is used to receive the transmitted light of the beam splitter and send it to the scanning mechanism; the scanning mechanism is used to scan the light beam sent by the relay unit and send it to the imaging mechanism; the imaging mechanism is used to perform imaging scanning according to the received light beam.

2. The all-optical high-speed multi-photon scanning imaging device according to claim 1, characterized in that: m is greater than or equal to 0.1% and less than or equal to 10%.

3. The all-optical high-speed multi-photon scanning imaging device according to claim 2, characterized in that: m is 1.25%.

4. The all-optical high-speed multi-photon scanning imaging device according to claim 1, characterized in that: a is greater than or equal to 0.01 and less than or equal to 0.

1.

5. The all-optical high-speed multi-photon scanning imaging device according to claim 4, characterized in that: a is 0.

08.

6. The all-optical high-speed multi-photon scanning imaging device according to claim 1, characterized in that: It also includes a precision moving stage, the moving direction of which is 90 degrees to the incident optical axis of the laser; and the first reflecting mirror is fixed on the precision moving stage.

7. The all-optical high-speed multi-photon scanning imaging device according to claim 1, characterized in that: Also included is a precision rotating stage on which the mirror is mounted.

8. The all-optical high-speed multi-photon scanning imaging device according to claim 1, characterized in that: The scanning mechanism includes two scanning galvanometers arranged in sequence along the optical path. The first scanning galvanometer is used to scan the light beam in the X-axis and then send it to the second scanning galvanometer. The second scanning galvanometer is used to scan the light beam in the Y-axis and then send it to the imaging mechanism.

9. The all-optical high-speed multi-photon scanning imaging device according to claim 1, characterized in that: The relay part includes two groups of relay lenses, the beam splitter is located at a focus of the first group of relay lenses, the other focus of the first group of relay lenses coincides with a focus of the second group of relay lenses, and the other focus of the second group of relay lenses is located on the scanning surface of the first scanning galvanometer.

Images