One-dimensional and two-dimensional simultaneous diagnosis shock wave velocity measurement system

Abstract

The invention discloses a one-dimensional and two-dimensional simultaneous diagnosis shock wave velocity measurement system, and relates to the technical field of shock wave velocity diagnosis. The system comprises a targeting light receiving unit, a one-dimensional line imaging unit and a two-dimensional velocity field unit which are arranged on the same light path, the target shooting light receiving unit comprises a light receiving module and a target spot; the one-dimensional line imaging unit comprises a probe light injection module, a light splitting module, a first beam splitter, a first reflector, an interference module and a one-dimensional continuous velocity field measurement module; the two-dimensional velocity field unit comprises a two-dimensional dynamic velocity field diagnosis module; the two-dimensional dynamic velocity field diagnosis module comprises an integration branch and a compression coding branch. According to the system provided by the invention, in the process of performing one-dimensional and two-dimensional shock wave velocity field diagnosis, one-dimensional shock wave velocity evolution and two-dimensional velocity field non-uniformity evolution data can be simultaneously obtained in a single-shot experiment, the overall structure is compact, and a foundation is laid for shock wave velocity multi-dimensional diagnosis.

Description

Technical Field

[0001] The present invention relates to the technical field of shock wave velocity diagnosis, and in particular, to a one-dimensional and two-dimensional simultaneous diagnosis shock wave velocity measurement system. Background Art

[0002] Shock wave velocity diagnosis plays an important role in many high energy density physics research fields. In the research of laser inertial confinement fusion (ICF), through the accurate diagnosis of ion velocity and shock wave velocity in the microsecond to nanosecond transient process, the research of shock pressure, shock symmetry, etc. can be realized. At the same time, in order to achieve an ideal compression state in the ICF process, it is required that the shock wave has extremely high spherical symmetry. However, due to the existence of various non-ideal factors, large-scale hydrodynamic instability structures will be formed under the action of the shock wave, resulting in the destruction of spherical compression. Therefore, it is of great significance to realize the diagnosis of two-dimensional shock wave non-uniformity.

[0003] The imaging type velocity interferometer for any reflector (VISAR) is a widely used velocity diagnosis technology. It mainly utilizes the optical Doppler effect, obtains the wavefront reflected light frequency change information through optical mixing technology, and records the fringe image through a streak camera with high time resolution. The accurate diagnosis of the shock wave velocity is realized by solving the change information of the fringe phase. Currently, the most maturely developed is the one-dimensional line VISAR, which can obtain the evolution information of the shock wave velocity in one-dimensional space over time. The two-dimensional VISAR developed on this technology can realize the diagnosis of the two-dimensional shock wave velocity field. However, the above technologies can only diagnose the surface to be measured separately through their respective optical paths at present, and cannot achieve single-shot simultaneous measurement. Summary of the Invention

[0004] In order to overcome the problem that in the process of one-dimensional and two-dimensional shock wave velocity field diagnosis in the prior art, only the surface to be measured can be diagnosed separately through their respective optical paths, and single-shot simultaneous measurement cannot be achieved, the purpose of the present invention is to propose a one-dimensional and two-dimensional simultaneous diagnosis shock wave velocity measurement system, which can obtain the one-dimensional shock wave velocity evolution and two-dimensional velocity field non-uniformity evolution data simultaneously in a single-shot experiment during the process of one-dimensional and two-dimensional shock wave velocity field diagnosis.

[0005] To achieve the purpose of the present invention, the present invention is implemented by adopting the following technical solutions: A one-dimensional and two-dimensional simultaneous diagnosis shock wave velocity measurement system, the system includes: a target shooting and light receiving unit, a one-dimensional line imaging unit, and a two-dimensional velocity field unit arranged on the same optical path; The target shooting and light collecting unit includes a light collecting module and a target point; the one-dimensional line imaging unit includes a probe light injection module, a first beam splitter, a first reflector, an interference module, and a one-dimensional continuous velocity field measurement module; the two-dimensional velocity field unit includes a two-dimensional dynamic velocity field diagnosis module; the two-dimensional dynamic velocity field diagnosis module includes an integration branch and a compression coding branch; The probe light injection module is used to emit probe light into the system. The first beam splitter refracts the probe light into the light collecting module. The light collecting module converges the probe light to the target point. The target point reflects the probe light through the moving target surface, so that the probe light carries Doppler frequency shift information and returns to the first beam splitter along the original path. The first beam splitter refracts the probe light carrying Doppler frequency shift information to the first reflector. The first reflector reflects the probe light carrying Doppler frequency shift information to the interference module; The interference module splits and interferes the incident probe light carrying Doppler frequency shift information into two interference lights carrying Doppler frequency shift information of the target surface at different times. One of the interference lights enters the one-dimensional continuous velocity field measurement module. The one-dimensional continuous velocity field measurement module records the image of the fringe change with time in one-dimensional space according to this interference light, and solves the phase of this pair of images to obtain the absolute value of the shock wave velocity of the velocity evolution with time in one-dimensional space; The other interference light enters the two-dimensional dynamic velocity field diagnosis module. The two-dimensional dynamic velocity field diagnosis module records the two-dimensional image of the integral of this interference light with time through the integration branch. The compression coding branch records the coded and compressed image according to this interference light, and based on the two-dimensional image and the coded and compressed image, uses a reconstruction algorithm to solve the two-dimensional velocity field information evolving with time.

[0006] In the above technical solution, the probe light carrying Doppler frequency shift information is split and interfered by the interference module into two interference lights carrying Doppler frequency shift information of the target surface at different times, and are respectively introduced into the one-dimensional continuous velocity field measurement module and the two-dimensional dynamic velocity field diagnosis module, realizing the simultaneous acquisition of one-dimensional shock wave velocity evolution and two-dimensional velocity field non-uniformity evolution data in a single-shot experiment, effectively reducing the manpower and material resources in the process of diagnosing one-dimensional and two-dimensional shock wave velocity fields, and the overall structure of the system is compact, laying a good technical foundation for the multi-dimensional diagnosis of shock wave velocity.

[0007] Preferably, the one-dimensional line imaging unit further includes a beam splitting module. The beam splitting module includes a third beam splitter, a fourth beam splitter, a seventh reflector, and an eighth reflector; wherein, an interference etalon is provided on the seventh reflector; The third beam splitter is used to split and refract the probe light emitted by the probe light injection module, and refract it to the seventh mirror and the eighth mirror respectively. The interference etalon on the seventh mirror interferes with the incident probe light, causing a time delay between the probe lights reflected by the seventh mirror and the eighth mirror. The fourth beam splitter refracts the two probe lights reflected by the seventh mirror and the eighth mirror at different times to the first beam splitter respectively, and the first beam splitter refracts these two probe lights to the light collection module respectively. Among them, the beam splitting module is used for the diagnosis of ps magnitude ultrafast and ultrashort physical processes.

[0008] Preferably, the one-dimensional line imaging unit further includes a beam splitting module, and the beam splitting module includes a seventh mirror and an eighth mirror. The seventh mirror is used to reflect the probe light emitted by the probe light injection module to the eighth mirror, the eighth mirror reflects the probe light to the first beam splitter, and the first beam splitter refracts the probe light to the light collection module. Among them, the beam splitting module is used for the diagnosis of physical processes of 10 ns magnitude.

[0009] In the above technical solution, by setting a beam splitting module in the system, the system can thus cope with the diagnosis of physical processes under different conditions and improve the accuracy of shock wave diagnosis. The beam splitting module composed of the third beam splitter, the fourth beam splitter, the seventh mirror and the eighth mirror can meet the diagnosis of ps magnitude ultrafast and ultrashort physical processes; while the beam splitting module composed of the seventh mirror and the eighth mirror is used for the diagnosis of physical processes of 10 ns magnitude, enabling the beam splitting module in this system to be flexibly replaced according to actual needs.

[0010] Preferably, the interference module includes a ninth mirror, a tenth mirror, a fifth beam splitter, a sixth beam splitter and a fourth mirror; among them, an interference etalon is provided on the tenth mirror. The fifth beam splitter is used to refract the probe light carrying Doppler frequency shift information reflected by the first mirror to the ninth mirror and the tenth mirror respectively. The interference etalon on the tenth mirror interferes with the incident probe light, causing a time delay between the probe lights reflected by the tenth mirror and the ninth mirror. The sixth beam splitter divides the two interference lights reflected by the ninth mirror and the tenth mirror at different times into two paths, one path is refracted to the fourth mirror, and the other path is refracted to the one-dimensional continuous velocity field measurement module. The fourth mirror reflects the incident light to the two-dimensional dynamic velocity field diagnosis module.

[0011] In the above technical solution, according to the structural design of the above interference module, during the interference of the probe light carrying Doppler frequency shift information, it is possible to divide the two interference lights at different times into two paths, and refract them to the one-dimensional continuous velocity field measurement module and the two-dimensional dynamic velocity field diagnosis module respectively for one-dimensional and two-dimensional shock wave velocity field diagnosis, so as to obtain the one-dimensional shock wave velocity evolution and two-dimensional velocity field non-uniformity evolution data simultaneously in a single-shot experiment.

[0012] Preferably, the one-dimensional continuous velocity field measurement module includes a second reflector, a third reflector and a first slit streak camera; wherein: The second reflector is used to reflect the interference light refracted by the sixth beam splitter to the third reflector, the third reflector is used to reflect the interference light reflected by the second reflector to the first slit streak camera, and the first slit streak camera is used to record the image of the fringe change over time in one-dimensional space according to the interference light, and the phase of the image can be solved by Fourier transform to obtain the absolute value of the shock wave velocity of the velocity evolution over time in one-dimensional space, and the expression is:

[0013] Wherein, represents the velocity sensitivity, which is defined as the velocity change represented by each moving fringe; represents the fringe change amount, which is defined as the change in the number of fringes of the dynamic fringe relative to the static fringe.

[0014] Preferably, the slit of the first slit streak camera is opened 100-200 μm.

[0015] In the above technical solution, opening the slit of the first slit streak camera 100-200 μm can more effectively obtain the one-dimensional velocity information on the velocity surface to be measured, so as to obtain a line VISAR image after scanning along the time direction, and further solve the phase of the image to obtain the absolute value of the shock wave velocity of the velocity evolution over time in one-dimensional space.

[0016] Preferably, the two-dimensional dynamic velocity field diagnosis module further includes a fifth reflector, a sixth reflector and a second beam splitter; The fifth reflector is used to reflect the interference light refracted by the fourth reflector to the sixth reflector, the sixth reflector reflects the interference light to the second beam splitter, and the second beam splitter refracts the interference light to the integration branch and the compression coding branch respectively.

[0017] Preferably, a two-dimensional integration recording device is provided on the integration branch, and a coding plate and a second slit streak camera are sequentially provided on the compression coding branch, wherein: The two-dimensional integral recording device is used to perform integral recording on the interference light refracted by the second beam splitter, so as to perform in-situ integral superposition on the two-dimensional image within the shock wave evolution time, and finally obtain an integrated two-dimensional image; The coding plate is used to encode the two-dimensional images refracted by the second beam splitter at different times, and then scan and compress them through the second slit fringe camera to obtain a coded compressed image; Wherein, the slit of the second slit streak camera is fully opened.

[0018] In the above technical solution, through the above structural design, the system can realize the two-dimensional velocity field inhomogeneity evolution data during the process of two-dimensional shock wave velocity field diagnosis.

[0019] Preferably, the process of using a reconstruction algorithm to obtain the two-dimensional velocity field information evolving over time includes: The dynamic process at the target point to be measured is recorded as , after random encoding operation of the encoding board The shear operation in the time direction of the second streak camera Then we get the expression:

[0020] After being recorded by the second streak camera, the final expression is:

[0021] in, In the equation, x and y represent the coordinates of any point in the space direction, and t represents the time process. Representing a dynamic process After random encoding The shear operation in the time direction of the second streak camera Then we get the process quantity, Represents a dynamic process Perform random encoding operation The shear operation in the time direction of the second streak camera , represents the spatiotemporal integration operation, represents the final image recorded by the second streak camera; Combining the above equations, the expression is:

[0022] in, , Represents a dynamic process Perform random encoding operation , the shear operation of the second streak camera in the time direction The spatio-temporal integration operation T; Reconstruct the original image from the image recorded by the two-dimensional integration recording device, and Perform back-solving to construct the target optimization problem, and the expression is:

[0023] Solve the target optimization problem, and the expression is:

[0024] Among them, represents the error term, represents the sparse term, represents the regularization parameter, represents the regularization function, represents the dynamic process of the 0-norm, represents the square of the 2-norm of.

[0025] Preferably, the system combines the absolute value of the shock wave velocity of the velocity evolution with time in one-dimensional space and the two-dimensional velocity field information of the two-dimensional shock wave evolution with time to achieve three-dimensional diagnosis of the shock wave.

[0026] In the above technical solution, the reconstruction algorithm can quickly and effectively solve the two-dimensional velocity field information evolving with time, so as to realize the non-uniform evolution data of the two-dimensional velocity field, and further enable the system to combine the absolute value of the shock wave velocity of the velocity evolution with time in one-dimensional space and the two-dimensional velocity field information of the two-dimensional shock wave evolution with time to achieve three-dimensional diagnosis of the shock wave.

[0027] Compared with the prior art, the beneficial effects of the present invention are as follows: The present invention provides a one-dimensional and two-dimensional simultaneous diagnostic shock wave velocity measurement system. The probe light carrying Doppler frequency shift information is split and interfered by the interference module into two interference lights carrying Doppler frequency shift information of the target surface at different times, and is respectively introduced into the one-dimensional continuous velocity field measurement module and the two-dimensional dynamic velocity field diagnostic module, realizing the simultaneous acquisition of one-dimensional shock wave velocity evolution and two-dimensional velocity field non-uniformity evolution data in a single-shot experiment, effectively reducing the manpower and material resources in the process of diagnosing the one-dimensional and two-dimensional shock wave velocity fields, and the overall structure of the system is compact, laying a good technical foundation for multi-dimensional diagnosis of the shock wave velocity. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 is a schematic structural diagram of a one-dimensional and two-dimensional simultaneous diagnostic shock wave velocity measurement system provided by an embodiment of the present application; Figure 2 is a first schematic structural diagram of the beam splitting module provided by an embodiment of the present application; Figure 3 Schematic diagram of the principle of spectroscopic interference provided by an embodiment of the present application; Figure 4 Second structural schematic diagram of the spectroscopic module provided by an embodiment of the present application; Figure 5 Schematic diagram of the velocity solution process by the Fourier transform method provided by an embodiment of the present application; Figure 6 Schematic diagram of the principle of simultaneous diagnosis of one-dimensional and two-dimensional shock wave velocities provided by an embodiment of the present application; Figure 7 Schematic diagram of the information of the one-dimensional spatial velocity field evolving with time provided by an embodiment of the present application; Figure 8 Schematic diagram of the two-dimensional velocity field information evolving with time provided by an embodiment of the present application; Figure 9 Schematic diagram of the three-dimensional diagnostic result provided by an embodiment of the present application. Detailed implementation manners

[0029] To facilitate the understanding of the present invention, the present invention will be described more comprehensively below with reference to the relevant drawings. Preferred embodiments of the present invention are shown in the drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, these embodiments are provided to make the understanding of the disclosure of the present invention more thorough and comprehensive.

[0030] It should be noted that when an element is referred to as being "fixed to" another element, it can be directly on the other element or there may also be an intermediate element. When an element is considered to be "connected" to another element, it can be directly connected to the other element or there may be an intermediate element at the same time. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are for illustrative purposes only.

[0031] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present invention belongs. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0032] Embodiment: This embodiment provides a one-dimensional and two-dimensional simultaneous diagnosis shock wave velocity measurement system. Refer to Figure 1 , the system includes: a target shooting and light receiving unit, a one-dimensional line imaging unit, and a two-dimensional velocity field unit arranged on the same optical path; The target shooting and light collecting unit includes a light collecting module and a target point; the one-dimensional line imaging unit includes a probe light injection module, a first beam splitter BS1, a first mirror M1, an interference module, and a one-dimensional continuous velocity field measurement module; the two-dimensional velocity field unit includes a two-dimensional dynamic velocity field diagnosis module; the two-dimensional dynamic velocity field diagnosis module includes an integration branch and a compression coding branch; The probe light injection module is used to emit probe light into the system. The first beam splitter BS1 refracts the probe light into the light collecting module. The light collecting module converges the probe light to the target point. The target point reflects the probe light through the moving target surface, so that the probe light carries Doppler frequency shift information and returns to the first beam splitter BS1 along the original path. The first beam splitter BS1 refracts the probe light carrying Doppler frequency shift information to the first mirror M1. The first mirror M1 reflects the probe light carrying Doppler frequency shift information to the interference module; The interference module splits and interferes the incident probe light carrying Doppler frequency shift information into two interference lights carrying Doppler frequency shift information of the target surface at different times; one of the interference lights enters the one-dimensional continuous velocity field measurement module. The one-dimensional continuous velocity field measurement module records the image of the fringe changing with time in one-dimensional space according to the interference light, and solves the phase of the image to obtain the absolute value of the shock wave velocity of the velocity evolving with time in one-dimensional space; The other interference light enters the two-dimensional dynamic velocity field diagnosis module. The two-dimensional dynamic velocity field diagnosis module records the two-dimensional image of the interference light integrated with time through the integration branch. The compression coding branch records the coded and compressed image according to the interference light, and based on the two-dimensional image and the coded and compressed image, uses a reconstruction algorithm to solve the two-dimensional velocity field information evolving with time; Among them, the one-dimensional continuous velocity field measurement module is a one-dimensional line VISAR module; the two-dimensional dynamic velocity field diagnosis module is a CUP-VISAR (Compressed Ultrafast Photography-Velocity InterferometerSystem for Any Reflector) module.

[0033] As a preferred embodiment, see Figure 1 And Figure 2 , the one-dimensional line imaging unit further includes a beam splitting module, and the beam splitting module includes a third beam splitter BS3, a fourth beam splitter BS4, a seventh mirror M7, and an eighth mirror M8; among them, an interference etalon is provided on the seventh mirror M7; The third beam splitter BS3 is used to split and refract the probe light emitted by the probe light injection module, and refract it to the seventh mirror M7 and the eighth mirror M8 respectively. The interference etalon on the seventh mirror M7 interferes with the incident probe light, causing a time delay between the probe lights reflected by the seventh mirror M7 and the eighth mirror M8. The fourth beam splitter BS4 refracts the two beams of probe light reflected by the seventh mirror M7 and the eighth mirror M8 at different times to the first beam splitter BS1 respectively, and the first beam splitter BS1 refracts these two beams of probe light to the light collection module respectively; Among them, the beam splitting module is used for the diagnosis of ps-level ultrafast and ultrashort physical processes.

[0034] Specifically, referring to Figure 2 , the beam splitting module shown in the figure structure is suitable for the diagnosis of ultrafast and ultrashort physical processes. At this time, the pulse width of the probe light is of ps level. After being delayed by the interferometer etalon, the time difference between the two arms will be greater than the pulse width of the probe light itself, and no interference signal can be generated. To ensure that an interference signal can be obtained, a beam splitting module is designed to split the probe light into two, and the two beams of homologous probe light are divided into four after entering the interference module. As shown in Figure 3, the beam splitting module and the interference module are provided with etalons of the same thickness. Therefore, the two pulses at the intermediate time coincide in time (shown by the dark gray box in the lower right corner of Figure 3) and thus interfere.

[0035] As a preferred embodiment, referring to Figure 1 and Figure 4 , the one-dimensional line imaging unit further includes a beam splitting module, and the beam splitting module includes a seventh mirror M7 and an eighth mirror M8; The seventh mirror M7 is used to reflect the probe light emitted by the probe light injection module to the eighth mirror M8, and the eighth mirror M8 reflects the probe light to the first beam splitter BS1, and the first beam splitter BS1 refracts the probe light to the light collection module; Among them, the beam splitting module is used for the diagnosis of 10ns-level physical processes.

[0036] Specifically, referring to Figure 4 , the beam splitting module shown in the figure structure is suitable for the diagnosis of 10ns-level physical processes. At this time, the pulse width of the probe light used is 15ns, and the time delay of the two arms of the interferometer is much smaller than the probe light pulse, so there is no need to perform beam splitting interference. In order to keep the optical paths of the two structures equal, the third beam splitter BS3 in Figure 2 is replaced with the seventh mirror M7, and at the same time BS3 and BS4 are removed. In actual use, it can be flexibly replaced according to different diagnostic requirements.

[0037] It is understandable that by setting a beam splitting module in the system, the system can thus cope with physical process diagnostics under different conditions and improve the accuracy of shock wave diagnostics. The beam splitting module composed of the third beam splitter BS3, the fourth beam splitter BS4, the seventh mirror M7 and the eighth mirror M8 can meet the diagnostics of ps-level ultrafast and ultrashort physical processes; while the beam splitting module composed of the seventh mirror M7 and the eighth mirror M8 is used for the diagnostics of 10ns-level physical processes, enabling the beam splitting module in this system to be flexibly replaced according to actual needs.

[0038] As a preferred embodiment, refer to Figure 1 and Figure 3 , the interference module includes the ninth mirror M9, the tenth mirror M10, the fifth beam splitter BS5, the sixth beam splitter BS6 and the fourth mirror M4; wherein, an interference etalon is provided on the tenth mirror M10; The fifth beam splitter BS5 is used to refract the probe light carrying Doppler frequency shift information reflected by the first mirror M1 to the ninth mirror M9 and the tenth mirror M10 respectively. The interference etalon on the tenth mirror M10 interferes with the incident probe light, causing a time delay between the probe light reflected by the tenth mirror M10 and the ninth mirror M9. The sixth beam splitter BS6 divides the two interfering lights reflected by the ninth mirror M9 and the tenth mirror M10 at different times into two paths, one path is refracted to the fourth mirror M4, and the other path is refracted to the one-dimensional continuous velocity field measurement module. The fourth mirror M4 reflects the incident light to the two-dimensional dynamic velocity field diagnostic module.

[0039] It is understandable that according to the above structural design of the interference module, during the interference process of the probe light carrying Doppler frequency shift information, it is possible to divide the two interfering lights at different times into two paths and refract them to the one-dimensional continuous velocity field measurement module and the two-dimensional dynamic velocity field diagnostic module respectively for one-dimensional and two-dimensional shock wave velocity field diagnostics, so as to simultaneously obtain one-dimensional shock wave velocity evolution and two-dimensional velocity field non-uniformity evolution data in a single-shot experiment.

[0040] As a preferred embodiment, refer to Figure 1 , the one-dimensional continuous velocity field measurement module includes the second mirror M2, the third mirror M3 and the first slit streak camera OSC; wherein: The second mirror M2 is used to reflect the interfering light refracted by the sixth beam splitter BS6 to the third mirror M3. The third mirror M3 is used to reflect the interfering light reflected by the second mirror M2 to the first slit streak camera OSC. The first slit streak camera OSC is used to record the image of the fringe changing with time in one-dimensional space according to the interfering light, and the phase of the image can be solved by Fourier transform to obtain the absolute value of the shock wave velocity of the velocity evolving with time in one-dimensional space.

[0041] As a preferred embodiment, the slit of the first slit streak camera is opened by 100-200 μm.

[0042] Specifically, referring to Figure 5 , the leftmost cube represents the two-dimensional shock wave signal to be measured evolving with time. The slit of the streak camera, which is the recording device of the one-dimensional line VISAR, is opened by 100-200 μm to obtain the one-dimensional velocity information on the velocity surface to be measured. After scanning along the time direction, a line VISAR image is obtained, and further phase solving of the image can obtain the absolute value of the shock wave velocity of the velocity evolving with time in one-dimensional space. The velocity solving principle is as follows: The velocity solving formula for the VISAR image is: (1) Where represents the velocity sensitivity, defined as the velocity change represented by moving one fringe; represents the fringe change amount, defined as the change in the number of fringes of the dynamic fringe relative to the static fringe, and can also be expressed as the change in the wave number, that is , where refers to the phase change of the dynamic fringe relative to the static fringe.

[0043] In this embodiment, since the fringe change amount essentially corresponds to the change amount of the fringe phase in the VISAR result, the data processing finally becomes a process of solving the fringe phase. In this embodiment, the Fourier transform method is used for velocity solving, but it is not limited to the Fourier transform method. The push-pull algorithm, the multi-phase solving algorithm, or any other method that can obtain the fringe phase can be used for data processing.

[0044] The schematic diagram of the phase solving process by the Fourier transform method is shown in Figure 3. First, a region to be processed is selected from the VISAR image, and one-dimensional Fourier transform is performed along the spatial direction to obtain a frequency spectrum diagram. After filtering out the high-frequency information, inverse Fourier transform is performed to obtain the fringe position. The phase information of the full screen is obtained by traversing the entire time process, and finally the velocity is solved according to formula (1). It can be understood that opening the slit of the first slit streak camera by 100-200 μm can more effectively obtain the one-dimensional velocity information on the velocity surface to be measured, so that a line VISAR image can be obtained after scanning along the time direction, and further phase solving of the image can obtain the absolute value of the shock wave velocity of the velocity evolving with time in one-dimensional space.

[0045] As a preferred embodiment, referring to Figure 1 , the two-dimensional dynamic velocity field diagnosis module further includes a fifth mirror M5, a sixth mirror M6, and a second beam splitter BS2; The fifth mirror M5 is used to reflect the interference light refracted by the fourth mirror M4 to the sixth mirror M6. The sixth mirror M6 reflects the interference light to the second beam splitter BS2, and the second beam splitter BS2 refracts the interference light to the integral branch and the compression encoding branch respectively.

[0046] As a preferred embodiment, refer to Figure 1 , a two-dimensional integral recording device CCD is provided on the integral branch, and a coding plate ( Figure 1 at the P2 position in and a second slit streak camera OSC are successively provided on the compression encoding branch, where: The two-dimensional integral recording device CCD is used to integrally record the interference light refracted by the second beam splitter BS2, so as to integrally superimpose the two-dimensional images within the shock wave evolution time in situ, and finally obtain an integrated two-dimensional image; The coding plate is used to encode the two-dimensional images at different times refracted by the second beam splitter BS2, and then a coded compressed image is obtained by scanning and compressing through the second slit streak camera OSC;

[0047] It can be understood that through the above structural design, the system can realize the non-uniform evolution data of the two-dimensional velocity field during the diagnosis of the two-dimensional shock wave velocity field.

[0048] In this embodiment, refer to Figure 1 , the overall optical path of the system adopts a multi-stage imaging and amplification design: relative to the image point, P1 is the image plane position of the light receiving system, and the magnification is 8. Relative to P1, the magnification at P2 is 2, and a coding plate is placed here to encode the signal; the magnification at P3 is 4, and a streak camera with a fully opened slit is placed here to record the coded compressed signal; the magnification at P4 is 4, and an integral CCD is placed here to record the two-dimensional integral signal; the magnification at P5 is 2, and a one-dimensional slit streak camera is placed here to record the one-dimensional VISAR signal. The multi-stage imaging design can make the optical path arrangement more flexible, realize the overall compact design, and at the same time can effectively reduce the size of the optical elements.

[0049] In this embodiment, refer to Figure 1 And Figure 6, The working process is as follows: The probe laser emitted by the probe laser source enters the entire system through the probe light injection module. First, it is split or not split by the beam splitting module (designed according to specific requirements), and then enters the light receiving module through the first beam splitter BS1. The light receiving module converges the probe light at the target position. According to the Doppler principle, after being reflected by the moving target surface, the probe light carries the corresponding Doppler frequency shift information and returns along the original path. After passing through the first beam splitter BS1 and the first mirror M1, it enters the interference module. The interference module is an M-Z interferometer. By setting an etalon in one arm (i.e., the tenth mirror), a time delay is generated between the two arms, so that two beams of light carrying Doppler frequency shift information of the target surface at different times interfere with each other. One of the interfering light beams enters the line VISAR module, passes through the second mirror M2, the third mirror M3, and the corresponding imaging mirror, and enters the optical streak camera OSC to record the image of the fringe changing with time in one-dimensional space. The other interfering light beam passes through the fourth mirror M4 and the fifth mirror M5 and enters the two-dimensional velocity field unit of the instrument, that is, the CUP-VISAR module (the dotted line between M4 and M5 in the figure indicates that the light propagation here is in the vertical direction perpendicular to the paper surface). The CUP-VISAR module is divided into an integration branch and a compressed coding branch by the second beam splitter BS2. The integration branch records the two-dimensional image integrated over time through the CCD. The compressed coding branch sets a coding plate at the P2 position to encode the two-dimensional signal and finally enters the streak camera to record the encoded compressed signal. Using the corresponding reconstruction algorithm to solve the obtained image can obtain the two-dimensional velocity field information evolving with time. Among them, Figure 6 In the dashed box, the x-axis represents the spatial x direction, the y-axis represents the spatial y direction, and the t represents the time direction, which is only for illustration and has no actual unit and value.

[0050] As a preferred embodiment, the process of using the reconstruction algorithm to solve the two-dimensional velocity field information evolving with time includes: Denote the dynamic process at the target to be measured as , after the random coding operation of the coding plate and the shearing operation in the time direction of the second streak camera , the result obtained is, and the expression is: (2) Finally, after being recorded by the second streak camera, the result obtained is, and the expression is: (3) Among them, The x and y in represent the coordinates of any point in the spatial direction, t represents the time process, represents the dynamic process After the random coding operation and the shearing operation in the time direction of the second streak camera , the process quantity is obtained, Indicates a random encoding operation on a dynamic process and a shearing operation in the time direction of the second streak camera as well as a spatio-temporal integration operation , Indicates a spatio-temporal integration operation represents the final image obtained by recording with the second streak camera; Combining the above equations (2) and (3), the expression is: (4) wherein , Indicates a random encoding operation on a dynamic process and a shearing operation in the time direction of the second streak camera as well as a spatio-temporal integration operation T; Reconstruct the original image based on the image recorded by the two-dimensional integration recording device, and perform back-solving on to construct an objective optimization problem, the expression is: (5) (5) Solve the objective optimization problem, the expression is: (6) wherein represents the error term; represents the sparse term; represents the regularization parameter, whose function is to balance the proportion of the two terms; represents the regularization function to ensure the sparsity of the signal Indicates the 0-norm of the dynamic process and represents the square of the 2-norm of. Currently, there are many compression and restoration algorithms used to solve such problems, such as the nonlinear conjugate gradient method (CG), the sparse gradient projection algorithm (GPSR), and the two-step iterative shrinkage threshold algorithm (TwIST), etc.

[0051] As a preferred embodiment, the system combines the absolute value of the shock wave velocity evolving with time in one-dimensional space and the two-dimensional velocity field information of the two-dimensional shock wave evolving with time to achieve three-dimensional diagnosis of the shock wave.

[0052] Specifically, refer to Figure 8, the diagnostic object of the CUP-VISAR module is two-dimensional images at different times. The integration branch performs integration recording through a CCD camera, integrates and superimposes the two-dimensional images during the shock wave evolution time in-situ, and finally obtains an integrated image. The compression and encoding branch first encodes the two-dimensional images at different times using an encoding plate, then performs scanning compression through a streak camera with a fully opened slit to obtain an encoded and compressed image. Finally, by combining the integrated image, the encoded and compressed image, and the known encoding information, the two-dimensional images at different times can be reconstructed using a reconstruction and restoration optimization algorithm. By further solving each two-dimensional image, the two-dimensional velocity field information evolving with time can be obtained. It should be noted that the obtained here is the "fluctuation" information ΔV(x, y, tn) of the two-dimensional spatial velocity field at different times. To realize the spatial non-uniformity diagnosis of the two-dimensional shock wave, combined with Figure 7 the absolute velocity diagnosis of the one-dimensional line VISAR in Figure 9 , the one-dimensional V(x, t) is extended to V(x, y, t) to realize the three-dimensional diagnosis of the shock wave V(x, y, t). The results are as shown in Figure 7 . Among them, in Figure 8 , the coordinates of the four small figures are the same, as follows: X-axis: time (nanoseconds), Y-axis: space (micrometers), Z-axis: velocity (Km / s).

[0053] It can be understood that using the reconstruction algorithm can quickly and effectively solve the two-dimensional velocity field information evolving with time, thereby realizing the non-uniformity evolution data of the two-dimensional velocity field. Furthermore, the system can combine the absolute value of the shock wave velocity evolving with time in one-dimensional space and the two-dimensional velocity field information of the two-dimensional shock wave evolving with time to realize the three-dimensional diagnosis of the shock wave.

[0054] In this embodiment, the probe light carrying Doppler frequency shift information is split and interfered by the interference module into two interference lights carrying the Doppler frequency shift information of the target surface at different times, and are respectively introduced into the one-dimensional continuous velocity field measurement module and the two-dimensional dynamic velocity field diagnosis module, realizing the simultaneous acquisition of one-dimensional shock wave velocity evolution and two-dimensional velocity field non-uniformity evolution data in a single-shot experiment, effectively reducing the manpower and material resources in the diagnosis process of the one-dimensional and two-dimensional shock wave velocity fields. Moreover, the overall structure of the system is compact, laying a good technical foundation for the multi-dimensional diagnosis of the shock wave velocity.

[0055] The above are only embodiments of the present invention, and do not limit the patent scope of the present invention accordingly. Any equivalent structure or equivalent process transformation made using the specification and drawings of the present invention, or directly or indirectly applied in other related technical fields, shall be equally included in the patent protection scope of the present invention.

Claims

1. A one-dimensional and two-dimensional simultaneous diagnosis shock wave velocity measurement system, characterized in that, The system includes: a target shooting and light receiving unit, a one-dimensional line imaging unit, and a two-dimensional velocity field unit that are arranged on the same optical path; The target shooting and light receiving unit includes a light receiving module and a target point; the one-dimensional line imaging unit includes a probe light injection module, a first beam splitter (BS1), a first reflector (M1), an interference module, and a one-dimensional continuous velocity field measurement module; the two-dimensional velocity field unit includes a two-dimensional dynamic velocity field diagnosis module; the two-dimensional dynamic velocity field diagnosis module includes an integration branch and a compression coding branch; The probe light injection module is used to emit probe light into the system. The first beam splitter (BS1) refracts the probe light into the light receiving module. The light receiving module converges the probe light to the target point. The target point reflects the probe light through a moving target surface, so that the probe light carries Doppler frequency shift information and returns to the first beam splitter (BS1) along the original path. The first beam splitter (BS1) refracts the probe light carrying Doppler frequency shift information to the first reflector (M1). The first reflector (M1) reflects the probe light carrying Doppler frequency shift information to the interference module; The interference module performs spectral interference on the incident probe light carrying Doppler frequency shift information to obtain two interference lights carrying Doppler frequency shift information of the target surface at different times. One of the interference lights enters the one-dimensional continuous velocity field measurement module. The one-dimensional continuous velocity field measurement module records the image of the fringe changing with time in one-dimensional space according to this interference light, and performs phase solving on this pair of images to obtain the absolute value of the shock wave velocity of the velocity evolving with time in one-dimensional space; The other interference light enters the two-dimensional dynamic velocity field diagnosis module. The two-dimensional dynamic velocity field diagnosis module records the two-dimensional image of the integration of this interference light with time through the integration branch. The compression coding branch records the coded compressed image according to this interference light, and based on the two-dimensional image and the coded compressed image, uses a reconstruction algorithm to solve the two-dimensional velocity field information evolving with time.

2. The one-dimensional and two-dimensional simultaneous diagnosis shock wave velocity measurement system according to claim 1, characterized in that, The one-dimensional line imaging unit further includes a beam splitting module. The beam splitting module includes a third beam splitter (BS3), a fourth beam splitter (BS4), a seventh reflector (M7), and an eighth reflector (M8); wherein, an interference etalon is provided on the seventh reflector (M7); The third beam splitter (BS3) is used to split and refract the probe light emitted by the probe light injection module, and refract it to the seventh reflector (M7) and the eighth reflector (M8) respectively. The interference etalon on the seventh reflector (M7) interferes with the incident probe light, causing a time delay between the probe lights reflected by the seventh reflector (M7) and the eighth reflector (M8). The fourth beam splitter (BS4) refracts the two beams of probe lights reflected by the seventh reflector (M7) and the eighth reflector (M8) at different times to the first beam splitter (BS1) respectively. The first beam splitter (BS1) refracts these two beams of probe lights to the light receiving module respectively; Among them, the beam splitting module is used for the diagnosis of ps-level ultrafast and ultrashort physical processes.

3. The one-dimensional and two-dimensional simultaneous diagnosis shock wave velocity measurement system according to claim 1, characterized in that, The one-dimensional line imaging unit further includes a beam splitting module. The beam splitting module includes a seventh reflector (M7) and an eighth reflector (M8); The seventh mirror (M7) is configured to reflect the probe light emitted by the probe light injection module to the eighth mirror (M8). The eighth mirror (M8) reflects the probe light to the first beam splitter (BS1), and the first beam splitter (BS1) refracts the probe light to the light collection module. Among them, the beam splitting module is used for the diagnosis of physical processes in the order of 10 ns.

4. The one-dimensional and two-dimensional simultaneous diagnosis shock wave velocity measurement system according to claim 1, characterized in that, The interference module includes a ninth mirror (M9), a tenth mirror (M10), a fifth beam splitter (BS5), a sixth beam splitter (BS6), and a fourth mirror (M4). Among them, an interference etalon is provided on the tenth mirror (M10). The fifth beam splitter (BS5) is configured to refract the probe light carrying Doppler frequency shift information reflected by the first mirror (M1) to the ninth mirror (M9) and the tenth mirror (M10) respectively. The interference etalon on the tenth mirror (M10) interferes with the incident probe light, causing a time delay between the probe light reflected by the tenth mirror (M10) and the ninth mirror (M9). The sixth beam splitter (BS6) divides the two interference lights reflected by the ninth mirror (M9) and the tenth mirror (M10) at different times into two paths. One path is refracted to the fourth mirror (M4), and the other path is refracted to the one-dimensional continuous velocity field measurement module. The fourth mirror (M4) reflects the incident light to the two-dimensional dynamic velocity field diagnosis module.

5. The one-dimensional and two-dimensional simultaneous diagnosis shock wave velocity measurement system according to claim 4, characterized in that, The one-dimensional continuous velocity field measurement module includes a second mirror (M2), a third mirror (M3), and a first slit streak camera. Among them: The second mirror (M2) is configured to reflect the interference light refracted by the sixth beam splitter (BS6) to the third mirror (M3). The third mirror (M3) is configured to reflect the interference light reflected by the second mirror (M2) to the first slit streak camera. The first slit streak camera is configured to record the image of the stripe changing with time in one-dimensional space according to the interference light, and perform phase solving on the image by using Fourier transform to obtain the absolute value of the shock wave velocity of the velocity evolving with time in one-dimensional space. The expression is: Among them, represents the velocity sensitivity, which is defined as the velocity change amount represented by each moving fringe; represents the fringe change amount, which is defined as the change in the number of fringes of the dynamic fringe relative to the static fringe.

6. The one-dimensional and two-dimensional simultaneous diagnosis shock wave velocity measurement system according to claim 5, characterized in that, The slit of the first slit streak camera is opened 100 - 200 μm.

7. The one-dimensional and two-dimensional simultaneous diagnosis shock wave velocity measurement system according to claim 4, characterized in that, The two-dimensional dynamic velocity field diagnosis module further includes a fifth mirror (M5), a sixth mirror (M6), and a second beam splitter (BS2). The fifth mirror (M5) is configured to reflect the interference light refracted by the fourth mirror (M4) to the sixth mirror (M6). The sixth mirror (M6) reflects the interference light to the second beam splitter (BS2). The second beam splitter (BS2) refracts the interference light to the integration branch and the compression coding branch respectively.

8. The one-dimensional and two-dimensional simultaneous diagnosis shock wave velocity measurement system according to claim 7, characterized in that, A two-dimensional integration recording device is provided on the integration branch. A coding plate and a second slit streak camera are sequentially provided on the compression coding branch. Among them: The two-dimensional integration recording device is configured to perform integration recording on the interference light refracted by the second beam splitter (BS2) to perform in-situ integration and superposition on the two-dimensional image during the shock wave evolution time, and finally obtain an integrated two-dimensional image. The coding plate is used to encode the two-dimensional images refracted by the second beam splitter (BS2) at different times, and then scan and compress them through the second slit fringe camera to obtain a coded compressed image; Wherein, the slit of the second slit streak camera is fully opened.

9. The one-dimensional and two-dimensional simultaneous diagnosis shock wave velocity measurement system according to any one of claims 1-8, characterized in that, The process of using the reconstruction algorithm to solve the two-dimensional velocity field information evolving over time includes: Denote the dynamic process at the target to be measured as , after the random encoding operation of the encoding plate and the shearing operation in the time direction of the second streak camera to obtain, the expression is: After being recorded by the second streak camera, the final expression is: Among them, x and y in it represent the coordinates of any point in the spatial direction, and t represents the time process. represents the dynamic process After undergoing the random encoding operation and the shearing operation in the time direction of the second streak camera the process quantity is obtained. represents the random encoding operation on the dynamic process and the shearing operation in the time direction of the second streak camera , represents the spatio-temporal integration operation, represents the final image recorded by the second streak camera; Combining the above equations, the expression is: Among them, , represents a random encoding operation on the dynamic process , a shearing operation in the time direction of the second stripe camera and a spatio-temporal integration operation T; Reconstruct the original image from the image recorded by the two-dimensional integral recording device, and perform inverse solution on to construct a target optimization problem, and the expression is: Solve the target optimization problem, the expression is: Among them, represents the 0-norm of the dynamic process, represents the square of the 2-norm of represents the error term, represents the sparse term, represents the regularization parameter, represents the regularization function.

10. The one-dimensional and two-dimensional simultaneous diagnosis shock wave velocity measurement system according to claim 9, characterized in that, The system combines the absolute value of the shock wave velocity evolving with time in one-dimensional space and the two-dimensional velocity field information evolving with time of the two-dimensional shock wave to realize three-dimensional diagnosis of the shock wave.

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