An ultrafast imaging device and method

Abstract

The application discloses an ultrafast imaging device and method, which comprises, along an optical path, an ultra-short pulse laser, a time-domain shaping mechanism for separating the ultra-short laser pulse into light of different wavelengths and separating the light of different wavelengths in time, a space-domain shaping mechanism for separating the light of different wavelengths after time separation into multiple regions and converting the light into multiple parallel light beams to irradiate the sample at different incident angles, an objective lens for multiple frame imaging of the sample after irradiating the sample, a second convex lens array for mapping each frame of image to different positions of a high-speed camera, and a high-speed camera for simultaneously capturing multiple frames of images of the ultrafast phenomenon. The application has the advantages of simple structure, high stability, convenient operation, conventional elements, low cost for capturing the ultrafast phenomenon, flexible setting of the imaging time scale in the range of femtosecond or picosecond, and integration of multiple super-resolution and high-field methods.

Description

Technical Field

[0001] This invention belongs to the field of ultrafast imaging technology, specifically relating to an ultrafast imaging device and method. Background Technology

[0002] Observing rapid dynamic events at the femtosecond or picosecond level in the microscopic world has been a significant challenge in many scientific research fields. These events include chemical reactions, changes in the state of matter, and biological dynamic processes, which are crucial for understanding fundamental physical processes and biological mechanisms. However, traditional high-speed photography techniques are often limited by frame rate and light source constraints. For example, existing high-speed cameras cannot achieve sufficient temporal resolution, or can only achieve nanosecond-level imaging by sacrificing 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 technique continues to play an irreplaceable role in scientific research across many fields. However, each pump-probe experiment can only provide information at one point in time. To obtain images over a series of time intervals, multiple measurements are required, making the operation complex. Furthermore, it cannot capture images of non-repeatable or low-repeatability phenomena.

[0004] With technological advancements, researchers have developed single-pulse ultrafast imaging methods, which require only a single pulse to detect the entire ultrafast process, enabling the imaging of non-repeatable and low-repeatability phenomena. Classic methods include compressed ultrafast photography and sequential time-lapse panoptic photography, but these techniques often require specialized instruments and customized components to capture femtosecond or picosecond-level phenomena, and they offer limited flexibility in controlling the captured frames, making them unsuitable for common shooting scenarios. Furthermore, these techniques face challenges in practical applications, including low resolution, high cost, low stability, and operational complexity. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of 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, which can achieve the capture of ultrafast phenomena at a low cost. The imaging timescale can be flexibly set in the range of femtoseconds or picoseconds, which is conducive to the integration of multiple super-resolution and high field-of-view methods.

[0006] This invention provides the following technical solution:

[0007] In a first aspect, an ultrafast imaging device is provided, comprising: arranged sequentially along an optical path:

[0008] Ultrashort pulse lasers are used to generate ultrashort laser pulses;

[0009] A time-domain shaping mechanism is used to split ultrashort laser pulses into light of different wavelengths and to separate the light of different wavelengths in time.

[0010] The spatial shaping mechanism is used to divide light of different wavelengths after time separation into multiple regions and convert them into multiple beams of parallel light to irradiate the sample at different incident angles.

[0011] Objective lens is used to capture light carrying sample information after illuminating the sample to create multi-frame images of the sample.

[0012] The second convex lens array is used to map each frame of image to different positions of the high-speed camera;

[0013] High-speed cameras are used to capture multiple frames of images of ultra-fast phenomena simultaneously.

[0014] Furthermore, the time-domain shaping mechanism includes a time-domain shaping element, a first grating, and a first convex lens arranged sequentially along the optical path; the time-domain shaping element includes one of a glass rod, a prism pair, and a dispersive element.

[0015] In the time-domain shaping mechanism, the time-domain shaping element can add positive dispersion to the ultrashort laser pulse and separate light of different wavelengths in time, thereby adjusting the pulse width to match the time scale required for imaging; the first grating is used to spatially disperse the pulse into multiple light of different wavelengths; the first convex lens is used to propagate the light of each different wavelength in a mutually parallel trend.

[0016] Furthermore, the time-domain shaping mechanism includes a first grating, a first convex lens, and a phase modulation element arranged sequentially along the optical path; the phase modulation element includes a phase-type liquid crystal spatial light modulator.

[0017] In the time-domain shaping mechanism, the first grating is used to spatially disperse the pulse into multiple different wavelengths of light; the first convex lens is used to propagate the light of each different wavelength in a parallel direction; the phase modulation element is used to divide the phase modulation element into multiple regions according to different wavelength ranges as needed for the number of output pulse sequences, 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.

[0018] 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.

[0019] Furthermore, the distance between the first grating and the first convex lens is the same as the focal length of the first convex lens.

[0020] Furthermore, the spatial shaping mechanism includes a first convex lens array, a second grating, a second convex lens, and a third convex lens arranged sequentially along the optical path.

[0021] In the spatial shaping mechanism, the first convex lens array is used to divide light of different wavelengths into multiple regions and converge them to the second grating respectively; the second grating is used to convert the converged light into multiple parallel light, but the parallel light is not parallel to each other and propagates according to the diffraction angle; the second convex lens is used to propagate the multiple parallel light in a parallel trend; the third convex lens is used to converge the multiple parallel light and irradiate the sample at the incident angle.

[0022] 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.

[0023] Furthermore, the first convex lens array includes a plurality of first sub-lenses arranged in a 1*n pattern, wherein the focal length of the first sub-lenses is the same as the focal length of the first convex lens.

[0024] The second convex lens array includes a plurality of second sub-lenses arranged in a 1*n pattern. The number of second sub-lenses is the same as that of the first sub-lenses. The focal length of the second sub-lens is equal to the focal length of the objective lens multiplied by the magnification of the objective lens. 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.

[0025] By designing the number of sub-lenses n in the first and second convex lens arrays, the number of frames can be adjusted.

[0026] Furthermore, the first grating and the second grating have the same scribe line density;

[0027] 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.

[0028] Furthermore, 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 that of the first convex lens.

[0029] 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;

[0030] And / or, the distance between the third convex lens and the second convex lens is twice the focal length of the second convex lens.

[0031] Furthermore, it also includes a sample imaging stage for placing the sample; a first reflecting mirror and a second reflecting mirror are provided vertically between the third convex lens and the sample imaging stage, and the distance between the sample imaging stage and the objective lens is the working distance of the objective lens.

[0032] 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.

[0033] Secondly, an ultrafast imaging method is provided, implemented using the ultrafast imaging device described in the first aspect, the method comprising the following steps:

[0034] An ultrashort laser pulse generated by an ultrashort laser is incident on a time-domain shaping mechanism;

[0035] The temporal shaping mechanism divides the ultrashort laser pulse into light of different wavelengths and separates the light of different wavelengths in time before it is incident on the spatial shaping mechanism.

[0036] The spatial shaping mechanism divides light of different wavelengths after time separation into multiple regions and converts them into multiple beams of parallel light that irradiate the sample at different incident angles.

[0037] After illuminating the sample, the light carrying 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.

[0038] The second convex lens array maps each frame of the image to a different position on the high-speed camera, allowing the high-speed camera to simultaneously capture multiple frames of images of the ultrafast phenomenon.

[0039] Compared with the prior art, the beneficial effects of the present invention are:

[0040] (1) The present invention generates ultrashort laser pulses by using an ultrashort pulse laser, divides the ultrashort laser pulses into light of different wavelengths by using a time-domain shaping mechanism, and performs time separation on the light of different wavelengths. Furthermore, the design of the time-domain shaping mechanism can realize the adjustment of pulse width or sub-pulse time interval, thereby realizing the control of frame interval.

[0041] (2) The present invention divides light of different wavelengths after time separation into multiple regions through a spatial shaping mechanism and converts it into multiple beams of parallel light that irradiate the sample at different incident angles. After irradiating the sample, the light carrying the sample information is used to perform multi-frame imaging of the sample through the objective lens. Each frame image is mapped to a different position of the high-speed camera through the second convex lens array. The high-speed camera simultaneously captures multiple frames of ultrafast phenomenon images. The design of the spatial shaping mechanism and the second convex lens array can achieve control of the number of frames.

[0042] (3) The ultrafast imaging device and method provided by the present invention have a simple structure, high device stability, convenient operation, and conventional components. They can capture ultrafast phenomena at a low cost. The imaging time scale can be flexibly set in the range of femtosecond or picosecond, which is conducive to the integration of multiple super-resolution and high field of view methods. Attached Figure Description

[0043] Figure 1 This is a schematic diagram of the ultrafast imaging device in Embodiment 1 of the present invention;

[0044] Figure 2 This is a schematic diagram of the convex lens array in an embodiment of the present invention;

[0045] Figure 3 This is a schematic diagram of the structure of the ultrafast imaging device in Embodiment 3 of the present invention;

[0046] The following are labeled in the figure: 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 imaging stage; 110, objective lens; 111, second convex lens array; 112, high-speed camera; 113, phase modulation element. Detailed Implementation

[0047] The present invention will be further described below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and should not be used to limit the scope of protection of the present invention.

[0048] In the description of this invention, it should be understood that the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0049] Example 1

[0050] 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 imaging stage 109, an objective lens 110, a second convex lens array 111, and a high-speed camera 112 arranged sequentially 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 time-domain shaping element 102, a first grating 103, and a first convex lens 104 arranged sequentially along the optical path.

[0053] The time-domain shaping element 102 includes one of a glass rod, a prism pair, and a dispersive element. It is used to add positive dispersion to an ultrashort laser pulse and to separate light of different wavelengths in time, thereby adjusting the pulse width to match the required imaging time scale. The time-domain shaping element can be selected according to the required imaging time scale; in this embodiment, a glass rod is selected.

[0054] The first grating 103 is used to spatially disperse the pulse into multiple wavelengths of light. In this embodiment, the grating 103 has a line density of 1200 lp / mm.

[0055] The first convex lens 104 is used to propagate light of different wavelengths in a parallel manner, and its 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, which is f1 = 150 mm.

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

[0057] The first convex lens array 105 is used to divide 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, i.e., 2*f1=300mm. Figure 2 As shown, the first convex lens array 105 includes multiple first sub-lenses arranged in a 1*n pattern, such as... Figure 2 As shown; the focal length of the first sub-lens is the same as that of the first convex lens 104, both being f1=150mm. In this embodiment, n=10, meaning there are 10 first sub-lenses arranged in a 1*10 pattern.

[0058] The second grating 106 is used to convert multiple converged beams of light into multiple parallel beams, but the parallel beams are not parallel to each other and propagate according to the diffraction angle. The second grating 106 and the first grating 103 have the same scribe line density, 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.

[0059] The second convex lens 107 is used to propagate multiple parallel beams of light in a parallel manner. The focal length of the second convex lens 107 is f2 = 200 mm, 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, i.e., f2 - f1 = 50 mm.

[0060] The third convex lens 108 is used to converge multiple parallel beams of light and illuminate the sample at an incident angle. The third convex lens 108 and the second convex lens 107 have the same focal length, which is f2 = 200 mm; 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, which is 2 * f2 = 400 mm.

[0061] The sample imaging stage 109 is used to place the sample. A first reflector and a second reflector are arranged vertically between the third convex lens 108 and the sample imaging stage 109. The first reflector and the second reflector are for the convenience of drawing the system optical path diagram and have no practical function. The distance between them is unlimited.

[0062] Objective lens 110 is used to capture light carrying sample information after illuminating the sample for multi-frame imaging. In this embodiment, objective lens 110 has a numerical aperture of 0.3, a magnification of 10, a working distance of 25 mm, and a focal length of f3 = 18 mm. The distance between objective lens 110 and sample imaging stage 109 is 25 mm.

[0063] The second convex lens array 111 is used to map each frame of image to different positions on the high-speed camera. The second convex lens array 111 includes a plurality of second sub-lenses arranged in a 1*n pattern, the number of which is the same as the number of the first sub-lenses; the focal length f4 of the second sub-lens = objective lens focal length * objective lens magnification = 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-lens, which is 198mm.

[0064] 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 111. The imaging time range is determined by the pulse width t after the ultrashort pulse passes through the time-domain shaping mechanism, and the interval between each frame is t / (n-1).

[0065] The high-speed camera 112 is used to capture multiple frames of images of ultrafast phenomena simultaneously. 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, which is f4=180mm.

[0066] Example 2

[0067] This embodiment provides a method for achieving ultrafast imaging using the device described in Embodiment 1, the steps of which are as follows:

[0068] Step 1: An ultrashort laser pulse is generated by an ultrashort pulse laser 101 (emitted pulse spectrum range 780nm~820nm, Gaussian distribution, pulse width 40fs) and incident on a glass rod of time-domain shaping element 102, thereby adjusting the pulse width of the ultrashort pulse from 40fs to 9ps. The pulse with adjusted pulse width is then incident on a first grating 103 and spatially dispersed into multiple wavelengths of light; then, the light of each wavelength is directed by a first convex lens 104 to propagate in a parallel manner.

[0069] Step 2: Light of different wavelengths propagating in parallel direction is divided into 10 regions after passing through the first convex lens array 105, and then converged onto the second grating 106. The second grating 106 converts these 10 converged beams into 10 parallel beams, but these 10 parallel beams are not parallel to each other and propagate according to the diffraction angle. After passing through the second convex lens 107, these 10 parallel beams propagate in a parallel direction. Then, after passing through the third convex lens 108, these 10 parallel beams are converged and irradiated onto the sample imaging stage 109 at different incident angles.

[0070] Step 3: After the 10 parallel beams illuminate the sample on the sample imaging stage 109, the light carrying sample information passes through the objective lens 110 at the incident angle. After the objective lens images the sample for 10 frames, each frame image is mapped onto a different position on the high-speed camera 112 via the second convex lens array 111. The high-speed camera 112 simultaneously captures the 10 frames of images of the ultrafast phenomenon. The maximum frame rate of the high-speed camera 112 should be greater than the repetition rate of the ultrashort pulse laser.

[0071] In this embodiment, the ultrashort pulses generated by the ultrashort pulse laser are transformed into ultrashort pulses with controllable pulse widths. Each sub-pulse of the ultrashort pulse is spatially separated 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 capture images of each frame at different positions. The method structure is simpler, the system is more stable, and it can achieve the capture of ultrafast phenomena at a lower cost, which is conducive to the integration of multiple super-resolution and high field-of-view methods.

[0072] Example 3

[0073] 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 imaging stage 109, an objective lens 110, a second convex lens array 111, and a high-speed camera 112 arranged sequentially along the optical path.

[0074] The ultrashort pulse laser 101 is used to generate ultrashort laser pulses.

[0075] The time-domain shaping mechanism includes a first grating 103, a first convex lens 104, and a phase modulation element 113 arranged sequentially along the optical path.

[0076] The first grating 103 is used to spatially disperse the pulse into multiple wavelengths of light. In this embodiment, the grating density of the first grating 103 is 1800 lp / mm.

[0077] The first convex lens 104 is used to propagate light of different wavelengths in a parallel manner, and its 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, which is f1 = 100 mm.

[0078] The phase modulation element 113 is used to output the required number of pulse sequences. The phase modulation element 113 is divided into multiple regions according to different wavelength ranges, each region containing different spectral components. Different phase modulation modes are set according to the time interval (frame interval) of the sub-pulses 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, i.e., f1 = 100 mm. In this embodiment, the phase modulation element 113 is a phase-type liquid crystal spatial light modulator, utilizing its programmable function to improve the system's flexibility in manipulating the image frame interval.

[0079] The spatial shaping mechanism includes a first convex lens array 105, a second grating 106, a second convex lens 107, and a third convex lens 108 arranged sequentially along the optical path.

[0080] The first convex lens array 105 is used to divide 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, i.e., 2*f1=200mm. The first convex lens array 105 includes multiple first sub-lenses arranged in a 1*n pattern, such as... Figure 2 As shown; the focal length of the first sub-lens is the same as that of the first convex lens 104, both being f1=100mm. In this embodiment, n=15, that is, the number of the first sub-lenses is 15, arranged in a 1*15 pattern.

[0081] The second grating 106 is used to convert multiple converged beams of light into multiple parallel beams, but the parallel beams are not parallel to each other and propagate according to the diffraction angle. The second grating 106 and the first grating 103 have the same scribe line density, 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.

[0082] The second convex lens 107 is used to propagate multiple parallel beams of light in a parallel manner. 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, i.e., f2-f1=50mm.

[0083] The third convex lens 108 is used to converge multiple parallel beams of light and illuminate the sample at an incident angle. The third convex lens 108 and the second convex lens 107 have the same focal length, which 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, which is 2*f2=300mm.

[0084] The sample imaging stage 109 is used to place the sample, and a first reflector and a second reflector are provided vertically between the third convex lens 108 and the sample imaging stage 109.

[0085] Objective lens 110 is used to capture light carrying sample information after illuminating the sample for multi-frame imaging. In this embodiment, objective lens 110 has a numerical aperture of 0.4, a magnification of 10, a working distance of 30 mm, and a focal length of f3 = 20 mm. The distance between objective lens 110 and sample imaging stage 109 is 30 mm.

[0086] The second convex lens array 111 is used to map each frame of image to different positions on the high-speed camera. The second convex lens array 111 includes a plurality of second sub-lenses arranged in a 1*n pattern, the number of which is the same as the number of the first sub-lenses; the focal length f4 of the second sub-lens = objective lens focal length * objective lens magnification = 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, which is 220mm.

[0087] The high-speed camera 112 is used to capture multiple frames of images of ultrafast phenomena simultaneously. 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, which is f4=200mm.

[0088] Example 4

[0089] This embodiment provides a method for achieving ultrafast imaging using the device described in Embodiment 3, the steps of which are as follows:

[0090] Step 1: An ultrashort laser pulse is generated by an ultrashort pulse laser 101 (the output pulse spectrum range is 780nm~820nm, with a Gaussian distribution and a pulse width of 40fs) and incident on the first grating 103, where it is spatially dispersed into multiple different wavelengths of light; then, the light of each different wavelength propagates in a parallel direction through the first convex lens 104.

[0091] Step 2: Inject light of different wavelengths propagating in parallel trend into phase modulation element 113 (liquid crystal spatial light modulator, resolution 1920*1200, bit depth 10bit, modulation range 0-2pi). According to the number of output pulse sequences required, the liquid crystal spatial light modulator is divided into 15 regions according to different wavelength ranges, each region containing different spectral components. According to the time interval (frame interval) of the sub-pulses set in each region, different phase modulation modes are set. The phase modulation mode to be loaded on the phase modulation element 113 is based on the work of Yang Kaining et al. ([1] Yang, Kaining, et al. Multidimensional ultrashort optical pulse manipulation using spatial lightmodulation. 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:

[0092] The phase modulation amount needs to be determined through calculation. The time interval between the 15 wavelength-divided regions is set to... . No. i Phase modulation amount of each wavelength of light in each region for:

[0093] ;

[0094] in, This represents the wavelength of light corresponding to that location. This 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 phase modulation requirements of the liquid crystal spatial light modulator and form the modulation mode loaded on the liquid crystal spatial light modulator.

[0095] Step 3: Light of different wavelengths is divided into 15 regions after passing through the first convex lens array 105, and then converged onto the second grating 106. The second grating 106 converts these 15 converged beams into 15 parallel beams, but these 15 parallel beams are not parallel to each other and propagate according to the diffraction angle. After passing through the second convex lens 107, these 15 parallel beams propagate in a parallel trend. Then, after passing through the third convex lens 108, these 15 parallel beams are converged and irradiated onto the sample imaging stage 109 at different incident angles.

[0096] Step 4: After the 15 parallel beams illuminate the sample on the sample imaging stage 109, the light carrying sample information passes through the objective lens 110 at the incident angle. After the objective lens images the sample for 15 frames, each frame image is mapped onto a different position of the high-speed camera 112 via the second convex lens array 111. The high-speed camera 112 simultaneously captures the 15 frames of images of the ultrafast phenomenon. The maximum frame rate of the high-speed camera 112 should be greater than the repetition rate of the ultrashort pulse laser.

[0097] This embodiment can capture ultrafast phenomena. All mentioned components are conventional, simple in structure, easy to operate, and allow for 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. Using the components and parameters mentioned in this embodiment, ultrafast imaging at 15 frames per second can be achieved. Furthermore, the first and second lens arrays can be replaced by programmable spatial light modulators instead of being customized, allowing for frame manipulation without altering the system structure, making the system more flexible.

[0098] In the above embodiments 1 to 4, there are no special restrictions on the selection of various parameters (such as the output parameters of the ultrashort pulse laser, the grating line density, the focal length f1, the focal length f2, the focal length f3, etc.). The parameters selected in the above embodiments are commonly used parameters in general systems. The parameters can be changed according to the actual system needs without affecting the functionality of the system.

[0099] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. An ultrafast imaging device, characterized in that, Including those arranged sequentially along the optical path: Ultrashort pulse lasers are used to generate ultrashort laser pulses; A time-domain shaping mechanism is used to divide an ultrashort laser pulse into light of different wavelengths and to separate the light of different wavelengths in time. The time-domain shaping mechanism includes a first convex lens. The spatial shaping mechanism is used to divide light of different wavelengths after time separation into multiple regions and convert them into multiple beams of parallel light to irradiate the sample at different incident angles. Objective lens is used to capture light carrying sample information after illuminating the sample to create multi-frame images of the sample. The second convex lens array is used to map each frame of image to different positions of the high-speed camera; High-speed cameras are used to simultaneously capture multiple frames of images of ultrafast phenomena. The spatial shaping mechanism includes a first convex lens array, a second grating, a second convex lens, and a third convex lens arranged sequentially along the optical path; The first convex lens array includes a plurality of first sub-lenses arranged in a 1*n pattern, wherein 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 a 1*n pattern. The number of second sub-lenses is the same as that of the first sub-lenses. The focal length of the second sub-lens is equal to the focal length of the objective lens multiplied by the magnification of the objective lens. 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.

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

3. The ultrafast imaging device according to claim 1, characterized in that, The time-domain shaping mechanism includes a first grating, a first convex lens, and a phase modulation element arranged sequentially 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 first grating and the second grating have the same scribe 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.

6. The ultrafast imaging device according to claim 2 or 3, 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 that 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.

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

8. An ultrafast imaging method, characterized in that, The method, implemented using the ultrafast imaging apparatus according to any one of claims 1 to 7, comprises the following steps: An ultrashort laser pulse generated by an ultrashort laser is incident on a time-domain shaping mechanism; The temporal shaping mechanism divides the ultrashort laser pulse into light of different wavelengths and separates the light of different wavelengths in time before it is incident on the spatial shaping mechanism. The spatial shaping mechanism divides light of different wavelengths after time separation into multiple regions and converts them into multiple beams of parallel light that irradiate the sample at different incident angles. After illuminating the sample, the light carrying 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 on the high-speed camera, allowing the high-speed camera to simultaneously capture multiple frames of images of the ultrafast phenomenon.

Images