Device for generating multiple beams of time sequence light based on pulse front edge inclination

Abstract

The invention discloses a device for generating multiple beams of time sequence light based on pulse front edge inclination, and relates to the technical field of ultrafast imaging, and the device comprises a long elliptical light beam generation system which is used for generating long elliptical light beams; the front-edge inclined pulse generation system is used for generating front-edge inclined pulses based on the oblong light beams output by the oblong light beam generation system; and the time sequence light beam generation system is used for dividing the pulse with the inclined front edge into a plurality of beams of time sequence light through a porous diaphragm. According to the method, multiple beams of time sequence light are generated by utilizing a pulse front edge inclination technology and then act with an ultrafast event to obtain an interferogram, a space-time coupling light field with space and time linearly associated can be constructed by utilizing the pulse front edge inclination technology in combination with a space coordinate transformation technology, and then each frame of image can be separated by utilizing a Fourier filtering technology; the number of pictures can be flexibly regulated and controlled by selecting a proper small hole array; the structure is simple and compact and reliability is high.

Description

Technical Field

[0001] The invention relates to the technical field of ultrafast imaging, and in particular to a device for generating multiple beams of sequential light based on pulse front tilt. Background Art

[0002] Ultrafast imaging is one of the hot topics of research, especially for some extremely short processes that are difficult to detect by ordinary means. Typical applications include real-time capture of transient phenomena such as laser-plasma interaction and photosynthesis. Existing ultrafast imaging technologies include spectral coding, frequency domain holography, spatial coding, and compressed ultrafast imaging, among which pump-probe imaging technology is widely used because of its simplicity and reliability. In addition, spectral coding technology of spatiotemporal information has also become one of the research hotspots.

[0003] Among ultrafast imaging technologies, pump-probe imaging technology is simple and reliable, while another special type is the spectrum encoding technology of spatiotemporal information. Before spectrum encoding, it is necessary to implement it from the perspective of time, that is, to use multiple pulses with different time delays, that is, sequential light, to illuminate the ultrafast process at different azimuths. Before realizing spectrum encoding, it is necessary to generate multiple pulses with different time delays through time encoding to construct a sequential light beam to illuminate and detect the ultrafast process. In order to achieve this goal, pulse front tilting technology has become an effective means. By regulating the pulse front, multiple beams of sequential light are generated. These sequential light beams can be used to capture and image ultrafast events.

[0004] At present, the sequential beam generation method based on pulse front tilt technology still has certain limitations, mainly reflected in the high system complexity, compact structure, and difficulty in image frame separation. Therefore, how to effectively and efficiently generate multiple sequential beams and combine them with spatial coordinate transformation technology to achieve efficient image separation for ultrafast imaging is an important challenge in current technology. Summary of the invention

[0005] The purpose of the present invention is to provide a device for generating multiple beams of sequential light based on a pulse front, which is used for ultrafast imaging of ultrafast objects. The device can efficiently generate multiple beams of sequential light to interact with ultrafast objects, thereby realizing ultrafast imaging. The device combines pulse front tilt technology with spatial coordinate transformation technology to flexibly control the generation of multiple beams of sequential light and realize efficient image separation.

[0006] In order to achieve the above object, the present invention provides the following technical solutions:

[0007] The present invention provides a device for generating multiple sequential lights based on pulse front tilt, comprising:

[0008] A long elliptical beam generating system, used for generating a long elliptical beam;

[0009] A leading edge tilted pulse generating system, used for generating a leading edge tilted pulse based on the long elliptical beam output by the long elliptical beam generating system;

[0010] The time-sequential beam generating system is used for dividing the pulse with tilted leading edge into a plurality of time-sequential beams through a multi-aperture aperture.

[0011] As a further solution of the present invention, the long elliptical beam generating system includes a first convex lens, a second convex lens, a first cylindrical lens, and a second cylindrical lens, which are used to convert the Gaussian pulse entering the long elliptical beam generating system into a long elliptical beam. The Gaussian pulse passes through the first convex lens, the second convex lens, the first cylindrical lens, and the second cylindrical lens of the long elliptical beam generating system in sequence to form a long elliptical beam.

[0012] As a further solution of the present invention, a fiber femtosecond laser generates a Gaussian pulse entering a long elliptical beam generation system, with a wavelength of 1030nm and a pulse width of the order of hundreds of femtoseconds.

[0013] As a further solution of the present invention, the multiple beams of sequential light are multiple beams of laser pulse signals output by a sequential light generating system. The sequential light beams have different time delays. The generated multiple beams of sequential light can interact with ultrafast events.

[0014] As a further solution of the present invention, in the long elliptical beam generating system, the focal length of the first convex lens is 200 mm, the focal length of the second convex lens is 50 mm, the focal length of the first cylindrical lens is 50 mm, and the focal length of the second cylindrical lens is 400 mm.

[0015] As a further solution of the present invention, the mirror surfaces of the first convex lens and the second convex lens are parallel to each other and the distance between them is 250 mm. The convex surface of the first convex lens is opposite to the advancing direction of the light beam, and the convex surface of the second convex lens is consistent with the advancing direction of the light beam.

[0016] The mirror surfaces of the first cylindrical lens and the second cylindrical lens are parallel to each other, the first cylindrical lens and the second cylindrical lens are 450 mm apart, and the angle between the x-axis and y-axis of the first cylindrical lens and the x-axis and y-axis of the second cylindrical lens is 0; the convex surface of the first cylindrical lens is opposite to the direction of the light beam, and the convex surface of the second cylindrical lens is consistent with the direction of the light beam.

[0017] As a further solution of the present invention, the front tilt pulse generation system includes an equilateral prism, the equilateral prism is made of H-ZF13 and has a size of 40×40×40 mm. 3 The long elliptical light beam is horizontally incident on the equilateral prism at a predetermined incident angle, so that the pulse front of the long elliptical light beam is tilted.

[0018] As a further solution of the present invention, the sequential beam generation system includes a small hole array aperture, the aperture is 40×50 mm2 The holes in the rectangular diaphragm are arranged linearly, with the center hole located at the intersection of the diagonals of the rectangular diaphragm. The hole diameter is 0.5mm, the hole interval is 3mm, and they are arranged in the horizontal direction in sequence.

[0019] In the above technical solution, the present invention provides a device for generating multiple sequential lights based on pulse front tilt, which has the following beneficial effects:

[0020] The present invention is based on a device for generating multiple beams of sequential light based on the tilting of the pulse front edge. After the multiple beams of sequential light are generated by the pulse front edge tilting technology, they interact with ultrafast events to obtain interference patterns. The pulse edge tilting technology combined with the spatial coordinate transformation technology can be used to construct a space-time coupled light field with linear correlation in space and time. Then, the Fourier filtering technology can be used to separate each frame of the image. The number of frames can be flexibly adjusted by selecting a suitable pinhole array. The structure is simple and compact with high reliability. In addition, a pseudo-random coding mask is used to replace the pinhole array, which is expected to achieve continuous scanning imaging of two-dimensional space and one-dimensional time. The multiple beams of sequential light generated by the present invention can interfere with ultrafast events. After obtaining the interference pattern, a space-time coupled light field with linear correlation in space and time is constructed as a coherent shutter for single ultrafast imaging. This space-time correlation can be used to achieve time-space frequency encoding between multiple images. The collected images can be separated into each frame using Fourier filtering technology, thereby achieving ultrafast imaging. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For ordinary technicians in this field, other drawings can also be obtained based on these drawings.

[0022] Figure 1 The present invention is a schematic structural diagram of a device for generating multiple sequential light beams based on pulse front tilt.

[0023] Figure 2 The present invention is a schematic structural diagram of a long elliptical light beam generating system in a device for generating multiple sequential light beams based on pulse front tilt.

[0024] Figure 3 The present invention is a schematic structural diagram of a leading edge tilted pulse generating system in a device for generating multiple sequential light beams based on pulse leading edge tilting.

[0025] Figure 4 The present invention is a schematic structural diagram of a sequential light beam generating system in a device for generating multiple sequential light beams based on pulse front tilt.

[0026] Reference numerals:

[0027] 11. Long elliptical beam generating system; 12. Front tilt pulse generating system; 13. Timing beam generating system; 21. First convex lens; 22. Second convex lens; 23. First cylindrical lens; 24. Second cylindrical lens; 31. Equilateral prism; 41. Pinhole array aperture. DETAILED DESCRIPTION

[0028] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be preferably described in detail below in conjunction with the accompanying drawings.

[0029] Since the current method for generating sequential light beams based on pulse front tilt technology still has certain limitations, which are mainly reflected in the high system complexity, the incompact structure and the difficulty in separating image frames. The purpose of the present invention is to provide a device for generating multiple sequential light beams based on pulse front tilt, which is used for ultrafast imaging of ultrafast objects. The device can efficiently generate multiple sequential light beams to interact with ultrafast objects, thereby realizing ultrafast imaging. The device combines pulse front tilt technology with spatial coordinate transformation technology, and can flexibly control the generation of multiple sequential light beams and realize efficient image separation.

[0030] In conjunction with the accompanying drawings, some embodiments of the present application are described in detail below. In the absence of conflict, the following embodiments and features in the embodiments can be combined with each other.

[0031] like Figure 1 As shown, an embodiment of the present invention provides a device for generating multiple sequential lights based on pulse front tilt, the device comprising:

[0032] The long elliptical beam generating system 11 is used to generate a long elliptical beam;

[0033] A leading edge tilted pulse generating system 12, for generating a leading edge tilted pulse based on the long elliptical beam output by the long elliptical beam generating system 11;

[0034] The sequential light beam generating system 13 is used to divide the pulse with tilted leading edge into multiple sequential light beams through a multi-aperture aperture.

[0035] This embodiment uses pulse front tilt technology to generate multiple beams of time-sequential light, which interact with ultrafast events to obtain interference patterns. The pulse edge tilt technology can be combined with spatial coordinate transformation technology to construct a space-time coupled light field with linear correlation in space and time, and then the Fourier filtering technology can be used to separate the image frames.

[0036] Specifically, in this embodiment, the femtosecond Gaussian pulse first enters the long elliptical beam generating system 11, and then generates a long elliptical beam, which then passes through the front tilt pulse generating system 12. After passing through the front tilt pulse generating system 12, the long elliptical beam will generate a pulse front tilt. Then it passes through the sequential beam generating system 13. In the sequential light generating system, it first passes through a customized pinhole array aperture 41, and the apertures in the aperture are arranged linearly. Multiple sequential lights are generated by the sequential light generating system.

[0037] In this embodiment, the multiple sequential light beams refer to multiple laser pulse signals output by the sequential light generation system, and the sequential light beams have different time delays. The generated multiple sequential light beams can interact with ultrafast events.

[0038] In this embodiment, the device for generating multiple sequential light beams based on pulse front tilt is to introduce pulse front tilt into the long elliptical light beam, and then generate multiple sequential light beams through a rectangular aperture. Specifically, in this embodiment, a fiber femtosecond laser is used to generate Gaussian pulses entering the long elliptical light beam generation system 11, with a wavelength of 1030nm and a pulse width of hundreds of femtoseconds.

[0039] It should be noted that, in specific implementation, the laser may be replaced with other lasers according to actual needs.

[0040] The multiple beams of sequential light generated by the present invention can interfere with ultrafast events, such as plasma, ultrafast rotating light field, etc. After obtaining the interference pattern, a space-time coupled light field with linear correlation in space and time is constructed as a coherent shutter for single ultrafast imaging. By utilizing this space-time correlation, time-space frequency encoding between multiple images can be achieved, and the collected images can be separated into each frame using Fourier filtering technology, thereby achieving ultrafast imaging.

[0041] In this embodiment, see Figure 2 As shown, the long elliptical beam generating system 11 includes a first convex lens 21, a second convex lens 22, a first cylindrical lens 23 and a second cylindrical lens 24, which are used to convert the Gaussian pulse entering the long elliptical beam generating system 11 into a long elliptical beam. The Gaussian pulse passes through the first convex lens 21, the second convex lens 22, the first cylindrical lens 23 and the second cylindrical lens 24 of the long elliptical beam generating system 11 in sequence to form a long elliptical beam.

[0042] Among them, the focal length of the first convex lens 21 in the long elliptical beam generating system 11 is 200 mm, the focal length of the second convex lens 22 is 50 mm, the focal length of the first cylindrical lens 23 is 50 mm, and the focal length of the second cylindrical lens 24 is 400 mm. The Gaussian laser pulses of 1030 nm and 6 mm in diameter generated by the femtosecond laser pass through the above components in sequence, and the incident mode is normal incidence.

[0043] In this embodiment, the mirror surfaces of the first convex lens 21 and the second convex lens 22 are parallel to each other, with a distance of 250 mm. The convex surface of the first convex lens 21 is opposite to the direction of the light beam, and the convex surface of the second convex lens 22 is consistent with the direction of the light beam; the mirror surfaces of the first cylindrical lens 23 and the second cylindrical lens 24 are parallel to each other, the first cylindrical lens 23 and the second cylindrical lens 24 are 450 mm apart, and the y-axis of the first cylindrical lens 23x and the y-axis of the second cylindrical lens 24x are 0; the convex surface of the first cylindrical lens 23 is opposite to the direction of the light beam, and the convex surface of the second cylindrical lens 24 is consistent with the direction of the light beam.

[0044] In this embodiment, see Figure 3 As shown, the leading edge tilt pulse generating system 12 includes an equilateral prism 31, the equilateral prism 31 is made of H-ZF13 and has a size of 40×40×40 mm. 3 The pulse with a tilted front edge is incident on the equilateral prism 31 horizontally at an incident angle calculated according to the minimum deflection angle of the prism.

[0045] Among them, calculate the minimum deflection angle δ m The formula is:

[0046]

[0047] In the formula, n is the refractive index of the prism, the material of the equilateral prism 31 is H-ZF13, the refractive index is 1.755, and α is the vertex angle, which is the equilateral prism 31 here.

[0048] In this embodiment, the incident angle i is calculated min The formula is:

[0049]

[0050] Specifically, after the long elliptical light beam passes through the equilateral prism 31, the pulse front is tilted, and the horizontal position delay is calculated according to the incident angle.

[0051] In this embodiment, see Figure 4 As shown, the sequential beam generation system 13 includes a small hole array aperture 41, the aperture is 40×50 mm 2 The holes in the rectangular diaphragm are arranged linearly, with the center hole located at the intersection of the diagonals of the rectangular diaphragm. The hole diameter is 0.5mm, the hole interval is 3mm, and they are arranged in the horizontal direction in sequence.

[0052] The number of linear holes is 5. The long elliptical pulse is divided into 5 sequential light beams after passing through the small hole array aperture 41. It should be noted that the interval of the holes can be flexibly set according to the experimental needs to generate the timing and number of light beams required for the experiment.

[0053] The present invention is based on a device for generating multiple beams of sequential light based on the tilting of the pulse front edge. After the multiple beams of sequential light are generated by the pulse front edge tilting technology, they interact with ultrafast events to obtain interference patterns. The pulse edge tilting technology combined with the spatial coordinate transformation technology can be used to construct a space-time coupled light field with linear correlation in space and time. Then, the Fourier filtering technology can be used to separate each frame of the image. The number of frames can be flexibly adjusted by selecting a suitable pinhole array. The structure is simple and compact with high reliability. In addition, a pseudo-random coding mask is used to replace the pinhole array, which is expected to achieve continuous scanning imaging of two-dimensional space and one-dimensional time. The multiple beams of sequential light generated by the present invention can interfere with ultrafast events. After obtaining the interference pattern, a space-time coupled light field with linear correlation in space and time is constructed as a coherent shutter for single ultrafast imaging. This space-time correlation can be used to achieve time-space frequency encoding between multiple images. The collected images can be separated into each frame using Fourier filtering technology, thereby achieving ultrafast imaging.

[0054] The terms used in the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The singular forms "a", "the" and "the" used in the present invention and the appended claims are also intended to include plural forms unless the context clearly indicates other meanings. It should also be understood that the term "and / or" used herein refers to and includes any or all possible combinations of one or more associated listed items.

[0055] It should be understood that although the terms first, second, third, etc. may be used in the present invention to describe various information, these information should not be limited to these terms. These terms are only used to distinguish the same type of information from each other. For example, without departing from the scope of the present invention, the first information may also be referred to as the second information, and similarly, the second information may also be referred to as the first information. Depending on the context, the word "if" as used herein may be interpreted as "at the time of" or "when" or "in response to determining".

[0056] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A device for generating multiple sequential light beams based on pulse front tilt, characterized in that: include: A long elliptical beam generating system, used for generating a long elliptical beam; A leading edge tilted pulse generating system, used for generating a leading edge tilted pulse based on the long elliptical beam output by the long elliptical beam generating system; The time-sequential beam generating system is used for dividing the pulse with tilted leading edge into a plurality of time-sequential beams through a multi-aperture aperture.

2. The device for generating multiple sequential lights based on pulse front tilt according to claim 1, characterized in that: The long elliptical beam generating system comprises a first convex lens, a second convex lens, a first cylindrical lens and a second cylindrical lens, and is used for converting Gaussian pulses entering the long elliptical beam generating system into a long elliptical beam.

3. The device for generating multiple sequential lights based on pulse front tilt according to claim 2, characterized in that: The device uses a fiber femtosecond laser to generate Gaussian pulses that enter the long elliptical beam generation system, and the pulse width is on the order of hundreds of femtoseconds.

4. The device for generating multiple sequential lights based on pulse front tilt according to claim 1, characterized in that: The multiple beams of sequential light are multiple beams of laser pulse signals output by a sequential light generation system. The sequential light beams have different time delays. The generated multiple beams of sequential light are used to interact with ultrafast events.

5. The device for generating multiple sequential lights based on pulse front tilt according to claim 2, characterized in that: In the long elliptical beam generating system, the focal length of the first convex lens is 200 mm, the focal length of the second convex lens is 50 mm, the focal length of the first cylindrical lens is 50 mm, and the focal length of the second cylindrical lens is 400 mm.

6. The device for generating multiple sequential lights based on pulse front tilt according to claim 5, characterized in that: The mirror surfaces of the first convex lens and the second convex lens are parallel to each other, the convex surface of the first convex lens is opposite to the advancing direction of the light beam, and the convex surface of the second convex lens is consistent with the advancing direction of the light beam.

7. The device for generating multiple sequential lights based on pulse front tilt according to claim 5, characterized in that: The mirror surfaces of the first cylindrical lens and the second cylindrical lens are parallel to each other, and the angle between the x and y axes of the first cylindrical lens and the x and y axes of the second cylindrical lens is 0; the convex surface of the first cylindrical lens is opposite to the direction of the light beam, and the convex surface of the second cylindrical lens is consistent with the direction of the light beam.

8. The device for generating multiple sequential lights based on pulse front tilt according to claim 1, characterized in that: The front-edge tilted pulse generating system comprises an equilateral prism. The long elliptical light beam is horizontally incident on the equilateral prism at a predetermined incident angle, so that the long elliptical light beam generates a tilted pulse front edge.

9. The device for generating multiple sequential lights based on pulse front tilt according to claim 1, characterized in that: The sequential light beam generating system comprises a small hole array diaphragm, the holes in the diaphragm are arranged linearly, the central hole is located at the intersection of the diagonal lines of the rectangular diaphragm, and the holes are arranged in sequence along the horizontal direction.

10. The device for generating multiple sequential lights based on pulse front tilt according to claim 9, characterized in that: The aperture is a rectangular aperture.

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