Ultrafast imaging device and method

Abstract

The invention discloses an ultrafast imaging device and an ultrafast imaging method. The ultrafast imaging device comprises an ultrashort pulse laser; the time domain shaping mechanism is used for dividing the ultrashort laser pulse into light with different wavelengths and separating the light with different wavelengths in time; the airspace shaping mechanism is used for dividing the light with different wavelengths after time separation into a plurality of regions and converting the light into a plurality of beams of parallel light to irradiate a sample at different incident angles; the objective lens is used for performing multi-frame imaging on the sample by using the light with the sample information after the sample is irradiated; the second convex lens array is used for mapping each frame of image to different positions of the high-speed camera; and the high-speed camera is used for simultaneously capturing multiple frames of images of the ultrafast phenomenon. The device is simple in structure, high in stability and convenient to operate, the used elements are conventional elements, the ultrafast phenomenon can be captured with low cost, the imaging time scale can be flexibly set in a femtosecond or picosecond level range, and integration of various super-resolution and high-view-field methods is facilitated.

Description

Technical Field

[0001] The present invention belongs to the technical field of ultrafast imaging, and in particular relates to an ultrafast imaging device and method. Background Art

[0002] In many fields of scientific research, observing fast dynamic events at the femtosecond or picosecond level in the microscopic world has always been an important challenge for scientific research. These events include chemical reactions, changes in the state of matter, and biological dynamic processes, which are crucial for understanding basic physical processes and biological mechanisms. However, traditional high-speed photography technology is often limited by frame rate and light source limitations. For example, existing high-speed cameras cannot achieve sufficient temporal resolution, or can only achieve nanosecond imaging at the expense of higher spatial resolution, and still cannot capture these ultrafast processes.

[0003] In the field of ultrafast imaging, the pump-probe method is a powerful tool with high temporal resolution and the ability to capture ultrafast dynamic events. This technology still plays an irreplaceable role in scientific research in many fields. However, each pump-probe experiment can only provide information at one point in time. In order to obtain images at a series of time intervals, multiple measurements are required, which is complicated to operate and cannot capture non-repeatable and low-repeatability phenomena.

[0004] With the advancement of technology, researchers have invented a single-pulse ultrafast imaging method, which only requires one pulse to detect the entire ultrafast process, making it possible to capture non-repeatable and low-repeatability phenomena. Classic methods include compressed ultrafast photography, sequential timing plenoptic mapping photography, and other technologies, but these technologies often require special instruments and customized components to capture femtosecond or picosecond level phenomena, and have low control flexibility for shooting frames, making them unsuitable for general shooting scenarios. In addition, these technologies face problems such as low resolution, high cost, low stability, and complex operation in practical applications. Summary of the invention

[0005] The purpose of the present invention is to overcome the deficiencies in the prior art and provide an ultrafast imaging device and method. The device has a simple structure, high stability, and convenient operation. The components used are conventional components, and the capture of ultrafast phenomena can be achieved at a relatively low cost. The imaging time scale can be flexibly set within the range of femtoseconds or picoseconds, which is conducive to the integration of multiple super-resolution and high field of view methods.

[0006] The present invention provides the following technical solutions: In a first aspect, an ultrafast imaging device is provided, comprising: Ultrashort pulse laser, used to generate ultrashort laser pulses; A time domain shaping mechanism is used to divide the ultrashort laser pulse into lights of different wavelengths and to perform temporal separation of the lights of different wavelengths; A spatial shaping mechanism is used to divide the time-separated light of different wavelengths into multiple regions and convert them into multiple beams of parallel light to irradiate the sample at different incident angles; An objective lens is used to perform multi-frame imaging of the sample using light carrying sample information after irradiating the sample; A second convex lens array is used to map each frame of the image to a different position of the high-speed camera; High-speed cameras are used to capture multiple frames of images of ultrafast phenomena simultaneously.

[0007] Furthermore, the time domain shaping mechanism includes a time domain shaping element, a first grating and a first convex lens which are sequentially arranged along the optical path; the time domain shaping element includes one of a glass rod, a prism pair and a dispersion element.

[0008] In the time domain shaping mechanism, the time domain shaping element can add forward dispersion to the ultrashort laser pulse and temporally separate light of different wavelengths, thereby adjusting the pulse width to match the time scale required for imaging; the first grating is used to spatially disperse the pulse into a plurality of lights of different wavelengths; and the first convex lens is used to propagate the lights of different wavelengths in a trend of being parallel to each other.

[0009] Furthermore, the time domain shaping mechanism includes a first grating, a first convex lens and a phase modulation element which are sequentially arranged along the optical path; the phase modulation element includes a phase-type liquid crystal spatial light modulator.

[0010] In the time domain shaping mechanism, the first grating is used to disperse the pulse space into a plurality of lights of different wavelengths; the first convex lens is used to propagate the lights of different wavelengths in a parallel manner; the phase modulation element is used to output the number of pulse sequences as required, and the phase modulation element is divided into a plurality of regions according to different wavelength ranges, each region containing different spectral components, and different phase modulation modes are set according to the time interval (frame interval) of the sub-pulses set in each region.

[0011] Furthermore, the distance between the first convex lens and the phase modulation element is the same as the focal length of the first convex lens.

[0012] Furthermore, the distance between the first grating and the first convex lens is the same as the focal length of the first convex lens.

[0013] Furthermore, the spatial shaping mechanism includes a first convex lens array, a second grating, a second convex lens and a third convex lens which are sequentially arranged along the optical path.

[0014] In the spatial shaping mechanism, the first convex lens array is used to divide the light of different wavelengths into multiple areas and converge them to the second grating respectively; the second grating is used to convert multiple beams of converged light into multiple beams of parallel light, but the parallel light beams are not parallel to each other and propagate according to the diffraction angle; the second convex lens is used to propagate the multiple beams of parallel light in a trend of being parallel to each other; the third convex lens is used to converge the multiple beams of parallel light and irradiate the sample at the incident angle.

[0015] Furthermore, when the time domain shaping mechanism includes the time domain shaping element, the distance between the first convex lens array and the first convex lens is twice the focal length of the first convex lens; when the time domain shaping mechanism includes the phase modulation element, the distance between the first convex lens array and the phase modulation element is the same as the focal length of the first convex lens.

[0016] Furthermore, the first convex lens array includes a plurality of first sub-lenses arranged in 1*n order, and the focal length of the first sub-lenses is the same as the focal length of the first convex lens; The second convex lens array includes a plurality of second sub-lenses arranged in 1*n, the number of the second sub-lenses is the same as that of the first sub-lenses, the focal length of the second sub-lenses=the focal length of the objective lens*the magnification of the objective lens, and the distance between the second convex lens array and the objective lens is the sum of the focal length of the objective lens and the focal length of the second sub-lenses.

[0017] The number of frames can be adjusted by designing the number n of sub-lenses in the first convex lens array and the second convex lens array.

[0018] Furthermore, the first grating and the second grating have the same line density; And / or, the distance between the second grating and the first convex lens array is the same as the focal length of the first convex lens.

[0019] Furthermore, the focal lengths of the second convex lens and the third convex lens are the same, and the focal length of the second convex lens is greater than the focal length of the first convex lens; And / or, the distance between the second convex lens and the second grating is the difference between the focal length of the second convex lens and the focal length of the first convex lens; And / or, the distance between the third convex lens and the second convex lens is twice the focal length of the second convex lens.

[0020] Furthermore, it also includes a sample shooting stage for placing samples; a first reflector and a second reflector arranged vertically are provided between the third convex lens and the sample shooting stage, and the distance between the sample shooting stage and the objective lens is the working distance of the objective lens.

[0021] Furthermore, the distance between the high-speed camera and the second convex lens array is the same as the focal length of the second sub-lens in the second convex lens array.

[0022] In a second aspect, an ultrafast imaging method is provided, which is implemented using the ultrafast imaging device described in the first aspect, and the method comprises the following steps: The ultrashort laser pulse generated by the ultrashort pulse laser is incident on the time domain shaping mechanism; The time domain shaping mechanism divides the ultrashort laser pulse into lights of different wavelengths, separates the lights of different wavelengths in time, and then inputs them into the space domain shaping mechanism; The spatial shaping mechanism divides the time-separated light of different wavelengths into multiple regions and converts them into multiple beams of parallel light to irradiate the sample at different incident angles; After irradiating the sample, the light with the sample information passes through the objective lens according to the incident angle, the objective lens performs multi-frame imaging of the sample, and then passes through the second convex lens array; The second convex lens array maps each frame of the image to a different position of the high-speed camera, and the high-speed camera simultaneously captures multiple frames of images of ultrafast phenomena.

[0023] Compared with the prior art, the present invention has the following beneficial effects: (1) The present invention generates ultrashort laser pulses by using an ultrashort pulse laser, divides the ultrashort laser pulses into lights of different wavelengths by using a time domain shaping mechanism, and separates the lights of different wavelengths in time. Furthermore, the pulse width or the sub-pulse time interval can be adjusted by the design of the time domain shaping mechanism, thereby realizing the control of the frame interval. (2) The present invention divides the time-separated light of different wavelengths into multiple regions through a spatial shaping mechanism, and converts them into multiple beams of parallel light to irradiate the sample at different incident angles. After irradiating the sample, the light with sample information is used to perform multi-frame imaging of the sample through an objective lens, and each frame of the image is mapped to a different position of a high-speed camera through a second convex lens array. The high-speed camera simultaneously captures multiple frames of images of ultrafast phenomena, wherein the design of the spatial shaping mechanism and the second convex lens array can realize the control of the number of frames; (3) The ultrafast imaging device and method provided by the present invention have a simple structure, high device stability, and convenient operation. The components used are conventional components, and can capture ultrafast phenomena at a relatively low cost. The imaging time scale can be flexibly set within the range of femtoseconds or picoseconds, which is conducive to the integration of multiple super-resolution and high field of view methods. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 is a schematic structural diagram of an ultrafast imaging device in Embodiment 1 of the present invention; Figure 2 is a schematic structural diagram of a convex lens array in an embodiment of the present invention; Figure 3 is a schematic structural diagram of an ultrafast imaging device in Embodiment 3 of the present invention; Marked in the figure are: 101, ultrashort pulse laser; 102, time domain shaping element; 103, first grating; 104, first convex lens; 105, first convex lens array; 106, second grating; 107, second convex lens; 108, third convex lens; 109, sample shooting stage; 110, objective lens; 111, second convex lens array; 112, high-speed camera; 113, phase modulation element. DETAILED DESCRIPTION

[0025] The present invention will be further described below in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and cannot be used to limit the protection scope of the present invention.

[0026] In the description of the present invention, it is to be understood that the terms "first", "second", etc. are used for descriptive purposes only and are not to be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first", "second", etc. may explicitly or implicitly include one or more of the feature. In the description of the present invention, unless otherwise specified, "plurality" means two or more.

[0027] Example 1

[0028] like Figure 1 As shown, this embodiment provides an ultrafast imaging device, including an ultrashort pulse laser 101, a time domain shaping mechanism, a spatial domain shaping mechanism, a sample shooting platform 109, an objective lens 110, a second convex lens array 111 and a high-speed camera 112 arranged in sequence along the optical path.

[0029] The ultrashort pulse laser 101 is used to generate ultrashort laser pulses.

[0030] The time domain shaping mechanism comprises a time domain shaping element 102, a first grating 103 and a first convex lens 104 which are sequentially arranged along the optical path.

[0031] The time domain shaping element 102 includes one of a glass rod, a prism pair, and a dispersion element, and is used to add forward dispersion to the ultrashort laser pulse and to temporally separate light of different wavelengths, thereby adjusting the pulse width to match the time scale required for imaging. The time domain shaping element can be selected according to the required imaging time scale, and a glass rod is selected in this embodiment.

[0032] The first grating 103 is used to spatially disperse the pulse into a plurality of lights of different wavelengths. In this embodiment, the line density of the first grating 103 is 1200 lp / mm.

[0033] The first convex lens 104 is used to propagate light of different wavelengths in a mutually parallel trend, and the focal length is f1. In this embodiment, f1=150 mm. The distance between the first grating 103 and the first convex lens 104 is the same as the focal length of the first convex lens 104, both of which are f1=150 mm.

[0034] The spatial shaping mechanism comprises a first convex lens array 105, a second grating 106, a second convex lens 107 and a third convex lens 108 which are sequentially arranged along the optical path.

[0035] The first convex lens array 105 is used to divide the light of different wavelengths into multiple regions and respectively converge them to the second grating 106. The distance between the first convex lens array 105 and the first convex lens 104 is twice the focal length of the first convex lens 104, that is, 2*f1=300mm. Figure 2 As shown, the first convex lens array 105 includes a plurality of first sub-lenses arranged in 1*n order, such as Figure 2 As shown, the focal length of the first sub-lens is the same as the focal length of the first convex lens 104, both of which are f1=150mm. In this embodiment, n=10, that is, the number of the first sub-lenses is 10, arranged in 1*10.

[0036] The second grating 106 is used to convert the multiple beams of converged light into multiple beams of parallel light, but the parallel light beams are not parallel to each other and propagate according to the diffraction angle. The second grating 106 has the same line density as the first grating 103, and the distance between the second grating 106 and the first convex lens array 105 is the same as the focal length of the first convex lens 104, that is, f1=150mm.

[0037] The second convex lens 107 is used to propagate the multiple beams of parallel light in a mutually parallel trend. The focal length of the second convex lens 107 is f2=200mm, and the distance between the second convex lens 107 and the second grating 106 is the difference between the focal length of the second convex lens 107 and the focal length of the first convex lens 104, that is, f2-f1=50mm.

[0038] The third convex lens 108 is used to converge multiple beams of parallel light and irradiate the sample at an incident angle. The focal length of the third convex lens 108 is the same as that of the second convex lens 107, that is, f2=200mm; the distance between the third convex lens 108 and the second convex lens 107 is twice the focal length of the second convex lens 107, that is, 2*f2=400mm.

[0039] The sample shooting platform 109 is used to place samples. A first reflector and a second reflector are vertically arranged between the third convex lens 108 and the sample shooting platform 109. The first reflector and the second reflector are for convenience in drawing the system optical path diagram, have no substantial function, and there is no limit to the distance between them.

[0040] The objective lens 110 is used to perform multi-frame imaging of the sample with the light carrying the sample information after irradiating the sample. In this embodiment, the numerical aperture of the objective lens 110 is 0.3, the magnification is 10, the working distance is 25 mm, and the focal length f3=18 mm. The distance between the objective lens 110 and the sample shooting stage 109 is 25 mm.

[0041] The second convex lens array 111 is used to map each frame of the image to different positions of the high-speed camera. The second convex lens array 111 includes a plurality of second sub-lenses arranged in 1*n order, and the number of the second sub-lenses is the same as that of the first sub-lenses; the focal length f4 of the second sub-lenses = the focal length of the objective lens * the magnification of the objective lens = 180mm, and the distance between the second convex lens array 111 and the objective lens 110 is the sum of the focal length f3 of the objective lens 110 and the focal length f4 of the second sub-lenses, that is, 198mm.

[0042] The number of frames can be adjusted by designing the number of sub-lenses n in the first convex lens array 105 and the second convex lens array 107. The imaging time range is determined by the pulse width t of the ultrashort pulse after passing through the time domain shaping mechanism. The interval between each frame is t / (n-1).

[0043] The high-speed camera 112 is used to simultaneously capture multiple frames of images of ultrafast phenomena. The distance between the high-speed camera 112 and the second convex lens array 111 is the same as the focal length of the second sub-lens in the second convex lens array 111, that is, f4=180 mm.

[0044] Example 2

[0045] This embodiment provides a method for realizing ultrafast imaging using the device described in Embodiment 1, and the steps are as follows: Step 1: Generate ultrashort laser pulses through ultrashort pulse laser 101 (with an output pulse spectrum range of 780nm~820nm, Gaussian distribution, and a pulse width of 40fs), and inject them into the glass rod of time domain shaping element 102, so that the pulse width of the ultrashort pulse is adjusted from 40fs to 9ps. The pulse with adjusted pulse width is injected into the first grating 103 to spatially disperse into multiple light of different wavelengths; then, the light of different wavelengths is propagated in a mutually parallel manner through the first convex lens 104.

[0046] Step 2: After the light of different wavelengths propagating in parallel passes through the first convex lens array 105, the light of each different wavelength is divided into 10 areas and respectively converged onto the second grating 106; the second grating 106 converts the 10 converged light beams into 10 parallel light beams, but the 10 parallel light beams are not parallel to each other and propagate according to the diffraction angle; the 10 parallel light beams are propagated in a trend of being parallel to each other through the second convex lens 107; and the 10 parallel light beams are converged through the third convex lens 108 and irradiated to the sample shooting stage 109 at different incident angles.

[0047] Step 3: After the 10 beams of parallel light irradiate the sample on the sample shooting stage 109, the light with sample information passes through the objective lens 110 according to the incident angle. After the objective lens images the sample for 10 frames, each frame of the image is mapped to a different position of the high-speed camera 112 through the second convex lens array 111; the high-speed camera 112 simultaneously captures 10 frames of ultrafast phenomenon images. The maximum shooting frame frequency of the high-speed camera 112 should be greater than the repetition frequency of the ultrashort pulse laser.

[0048] In this embodiment, the ultrashort pulse generated by the ultrashort pulse laser is converted into an ultrashort pulse with controllable pulse width, and each sub-pulse of the ultrashort pulse is separated in space and incident on the ultrafast phenomenon observation surface at different angles with a time interval of t / (n-1); through the design of the convex lens array, an ultrafast camera can be used to capture each frame of the image at different positions; the method has a simpler structure, a stable system, and can capture ultrafast phenomena at a lower cost, which is conducive to the integration of multiple super-resolution and high field of view methods.

[0049] Example 3

[0050] like Figure 3 As shown, this embodiment provides an ultrafast imaging device, including an ultrashort pulse laser 101, a time domain shaping mechanism, a spatial domain shaping mechanism, a sample shooting platform 109, an objective lens 110, a second convex lens array 111 and a high-speed camera 112 arranged in sequence along the optical path.

[0051] The ultrashort pulse laser 101 is used to generate ultrashort laser pulses.

[0052] The time domain shaping mechanism includes a first grating 103, a first convex lens 104 and a phase modulation element 113 which are sequentially arranged along the optical path.

[0053] The first grating 103 is used to spatially disperse the pulse into a plurality of lights of different wavelengths. In this embodiment, the line density of the first grating 103 is 1800 lp / mm.

[0054] The first convex lens 104 is used to propagate light of different wavelengths in a mutually parallel trend, and the focal length is f1. In this embodiment, f1=100 mm. The distance between the first grating 103 and the first convex lens 104 is the same as the focal length of the first convex lens 104, both of which are f1=100 mm.

[0055] The phase modulation element 113 is used to output the number of pulse sequences as required, and the phase modulation element 113 is divided into multiple regions according to different wavelength ranges. Each region contains different spectral components, and different phase modulation modes are set according to the time interval (frame interval) of the sub-pulses set in each region. The distance between the phase modulation element 113 and the first convex lens 104 is the same as the focal length of the first convex lens 104, that is, f1=100mm. In this embodiment, the phase modulation element 113 is a phase-type liquid crystal spatial light modulator, which uses its programmable function to enhance the system's flexibility in manipulating the image frame interval.

[0056] The spatial shaping mechanism comprises a first convex lens array 105, a second grating 106, a second convex lens 107 and a third convex lens 108 which are sequentially arranged along the optical path.

[0057] The first convex lens array 105 is used to divide the light of different wavelengths into multiple regions and converge them to the second grating 106. The distance between the first convex lens array 105 and the first convex lens 104 is twice the focal length of the first convex lens 104, that is, 2*f1=200mm. The first convex lens array 105 includes a plurality of first sub-lenses arranged in 1*n, such as Figure 2 As shown, the focal length of the first sub-lens is the same as the focal length of the first convex lens 104, both of which are f1=100mm. In this embodiment, n=15, that is, the number of first sub-lenses is 15, arranged in 1*15.

[0058] The second grating 106 is used to convert the multiple beams of converged light into multiple beams of parallel light, but the parallel light beams are not parallel to each other and propagate according to the diffraction angle. The second grating 106 has the same line density as the first grating 103, and the distance between the second grating 106 and the first convex lens array 105 is the same as the focal length of the first convex lens 104, that is, f1=100mm.

[0059] The second convex lens 107 is used to propagate the multiple parallel light beams in a mutually parallel trend. The focal length of the second convex lens 107 is f2=150mm, and the distance between the second convex lens 107 and the second grating 106 is the difference between the focal length of the second convex lens 107 and the focal length of the first convex lens 104, that is, f2-f1=50mm.

[0060] The third convex lens 108 is used to converge multiple beams of parallel light and irradiate the sample at an incident angle. The focal length of the third convex lens 108 is the same as that of the second convex lens 107, that is, f2=150mm; the distance between the third convex lens 108 and the second convex lens 107 is twice the focal length of the second convex lens 107, that is, 2*f2=300mm.

[0061] The sample shooting stage 109 is used to place the sample, and a first reflecting mirror and a second reflecting mirror which are vertically arranged are provided between the third convex lens 108 and the sample shooting stage 109 .

[0062] The objective lens 110 is used to perform multi-frame imaging of the sample with the light carrying the sample information after irradiating the sample. In this embodiment, the numerical aperture of the objective lens 110 is 0.4, the magnification is 10, the working distance is 30 mm, and the focal length f3=20 mm. The distance between the objective lens 110 and the sample shooting stage 109 is 30 mm.

[0063] The second convex lens array 111 is used to map each frame of the image to different positions of the high-speed camera. The second convex lens array 111 includes a plurality of second sub-lenses arranged in 1*n order, and the number of the second sub-lenses is the same as that of the first sub-lenses; the focal length f4 of the second sub-lenses = the focal length of the objective lens * the magnification of the objective lens = 200mm, and the distance between the second convex lens array 111 and the objective lens 110 is the sum of the focal length f3 of the objective lens 110 and the focal length f4 of the second sub-lens, that is, 220mm.

[0064] The high-speed camera 112 is used to simultaneously capture multiple frames of images of ultrafast phenomena. The distance between the high-speed camera 112 and the second convex lens array 111 is the same as the focal length of the second sub-lens in the second convex lens array 111, that is, f4=200 mm.

[0065] Example 4 This embodiment provides a method for realizing ultrafast imaging using the device described in Embodiment 3, and the steps are as follows: Step 1: An ultrashort laser pulse is generated by an ultrashort pulse laser 101 (with an output pulse spectrum range of 780nm~820nm, Gaussian distribution, and a pulse width of 40fs), and is incident on the first grating 103, and is spatially dispersed into a plurality of lights of different wavelengths; and then passes through the first convex lens 104 so that the lights of different wavelengths propagate in a mutually parallel manner.

[0066] Step 2: Light of different wavelengths propagating in parallel is incident on the phase modulation element 113 (liquid crystal spatial light modulator, resolution 1920*1200, bit depth 10bit, modulation range 0-2pi). According to the number of pulse sequences to be output, the liquid crystal spatial light modulator is divided into 15 regions according to different wavelength ranges, and each region contains different spectral components. Different phase modulation modes are set according to the time interval (frame interval) of the sub-pulses set in each region. The phase modulation mode to be loaded on the phase modulation element 113 refers to the work of Yang Kaining et al. ([1] Yang, Kaining, et al. Multidimensional ultrashort optical pulse manipulation using spatial light modulation. Optics Letters 49.15 (2024): 4246-4249; [2] Chinese invention patent application: A programmable ultrashort laser pulse time domain shaping method and device, publication number: CN118099903A), as follows: The phase modulation amount needs to be determined by calculation. Set the time interval size of the 15 regions divided by wavelength to . No. i The phase modulation amount of each light beam with different wavelengths in each area for: ; in, is the wavelength of light corresponding to this position, is the time offset correction amount. Since light is a periodic electromagnetic wave, the above phase modulation amount needs to be classified into 0~2π to meet the needs of phase modulation of the liquid crystal spatial light modulator and form a modulation mode loaded on the liquid crystal spatial light modulator.

[0067] Step 3, the light of different wavelengths is divided into 15 areas after passing through the first convex lens array 105, and is respectively converged onto the second grating 106; the second grating 106 converts the 15 converged light beams into 15 parallel light beams, but the 15 parallel light beams are not parallel to each other and propagate according to the diffraction angle; the 15 parallel light beams are propagated in a trend of being parallel to each other through the second convex lens 107; and the 15 parallel light beams are converged through the third convex lens 108 and irradiated to the sample shooting stage 109 at different incident angles.

[0068] Step 4: After the 15 beams of parallel light irradiate the sample on the sample shooting stage 109, the light with sample information passes through the objective lens 110 according to the incident angle. After the objective lens images the sample for 15 frames, each frame of the image is mapped to a different position of the high-speed camera 112 through the second convex lens array 111; the high-speed camera 112 simultaneously captures 15 frames of ultrafast phenomenon images. The maximum shooting frame frequency of the high-speed camera 112 should be greater than the repetition frequency of the ultrashort pulse laser.

[0069] This embodiment can be used to shoot ultrafast phenomena. The components mentioned are all conventional components with simple structure, easy operation, and flexible control of frame properties. Specifically, the number of frames and frame intervals can be changed by encoding the liquid crystal spatial light modulator according to experimental needs. If the components and parameters mentioned in this embodiment are used, ultrafast imaging of 15 frames can be achieved. In addition, the first lens array and the second lens array can be replaced by a programmable spatial light modulator instead of being customized, so that the frame can be manipulated without changing the system structure, and the system is more flexible.

[0070] In the above-mentioned Examples 1 to 4, there are no special restrictions on the selection of various parameters (such as ultrashort pulse laser output parameters, grating line density, focal length f1, focal length f2, focal length f3, etc.). The parameters selected in the above-mentioned embodiments are commonly used parameters in general systems, and the parameters can be changed according to the actual system needs without affecting the functionality of the system.

[0071] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. An ultrafast imaging device, characterized in that: Including the following arranged in sequence along the optical path: Ultrashort pulse laser, used to generate ultrashort laser pulses; A time domain shaping mechanism is used to divide the ultrashort laser pulse into lights of different wavelengths and to perform temporal separation of the lights of different wavelengths; A spatial shaping mechanism is used to divide the time-separated light of different wavelengths into multiple regions and convert them into multiple beams of parallel light to irradiate the sample at different incident angles; An objective lens is used to perform multi-frame imaging of the sample using light carrying sample information after irradiating the sample; A second convex lens array is used to map each frame of the image to a different position of the high-speed camera; High-speed cameras are used to capture multiple frames of images of ultrafast phenomena simultaneously.

2. The ultrafast imaging device according to claim 1, characterized in that: The time domain shaping mechanism comprises a time domain shaping element, a first grating and a first convex lens which are sequentially arranged along the optical path; The time domain shaping element includes one of a glass rod, a prism pair, and a dispersion element.

3. The ultrafast imaging device according to claim 1, characterized in that: The time domain shaping mechanism comprises a first grating, a first convex lens and a phase modulation element which are sequentially arranged along the optical path; The phase modulation element includes a phase-type liquid crystal spatial light modulator.

4. The ultrafast imaging device according to claim 2 or 3, characterized in that: The distance between the first grating and the first convex lens is the same as the focal length of the first convex lens.

5. The ultrafast imaging device according to claim 2 or 3, characterized in that: The spatial shaping mechanism comprises a first convex lens array, a second grating, a second convex lens and a third convex lens which are sequentially arranged along the optical path.

6. The ultrafast imaging device according to claim 5, characterized in that: The first convex lens array includes a plurality of first sub-lenses arranged in a 1*n pattern, and the focal length of the first sub-lenses is the same as the focal length of the first convex lens; The second convex lens array includes a plurality of second sub-lenses arranged in 1*n, the number of the second sub-lenses is the same as that of the first sub-lenses, the focal length of the second sub-lenses=the focal length of the objective lens*the magnification of the objective lens, and the distance between the second convex lens array and the objective lens is the sum of the focal length of the objective lens and the focal length of the second sub-lenses.

7. The ultrafast imaging device according to claim 5, characterized in that: The first grating and the second grating have the same line density; And / or, the distance between the second grating and the first convex lens array is the same as the focal length of the first convex lens.

8. The ultrafast imaging device according to claim 5, characterized in that: The second convex lens and the third convex lens have the same focal length, and the focal length of the second convex lens is greater than the focal length of the first convex lens; And / or, the distance between the second convex lens and the second grating is the difference between the focal length of the second convex lens and the focal length of the first convex lens; And / or, the distance between the third convex lens and the second convex lens is twice the focal length of the second convex lens.

9. The ultrafast imaging device according to claim 1, characterized in that: It also includes a sample shooting stage for placing samples; a first reflector and a second reflector arranged vertically are provided between the third convex lens and the sample shooting stage, and the distance between the sample shooting stage and the objective lens is the working distance of the objective lens.

10. An ultrafast imaging method, characterized in that: The method is implemented by using the ultrafast imaging device according to any one of claims 1 to 9, and comprises the following steps: The ultrashort laser pulse generated by the ultrashort pulse laser is incident on the time domain shaping mechanism; The time domain shaping mechanism divides the ultrashort laser pulse into lights of different wavelengths, separates the lights of different wavelengths in time, and then inputs them into the space domain shaping mechanism; The spatial shaping mechanism divides the time-separated light of different wavelengths into multiple regions and converts them into multiple beams of parallel light to irradiate the sample at different incident angles; After irradiating the sample, the light with the sample information passes through the objective lens according to the incident angle, the objective lens performs multi-frame imaging of the sample, and then passes through the second convex lens array; The second convex lens array maps each frame of the image to a different position of the high-speed camera, and the high-speed camera simultaneously captures multiple frames of images of ultrafast phenomena.

Images