Ultrahigh time resolution camera time characteristic detection device and method

Abstract

The invention relates to the technical field of optical precision measurement, in particular to an ultra-high time resolution camera time characteristic detection device and method, and the device comprises a laser source which is used for generating pulse laser; the polarization modulation element is arranged on an emergent light path of the laser source and is used for modulating the pulse laser into circularly polarized light; the spectroscope is arranged on an emergent light path of the polarization modulation element and is used for decomposing the circularly polarized light into a first linearly polarized light beam and a second linearly polarized light beam; the first optical path unit is used for guiding the first linearly polarized light beam to the cylindrical optical element along a fixed optical path; the second optical path unit is used for adjusting the optical path of the second linearly polarized light beam and guiding the second linearly polarized light beam to the cylindrical optical element; and the cylindrical optical element is used for receiving the first linearly polarized light beam and the second linearly polarized light beam and respectively projecting the first linearly polarized light beam and the second linearly polarized light beam to an imaging surface of a camera to be detected to form two spatially separated light spots. The objective of the invention is to improve camera time characteristic calibration precision and efficiency.

Description

Technical Field

[0001] This invention relates to the field of optical precision measurement technology, specifically to a device and method for detecting the time characteristics of ultra-high time resolution cameras. Background Technology

[0002] In cutting-edge physics research such as laser inertial confinement fusion, obtaining high-precision spatiotemporal information of transient processes relies on ultra-high time-resolution cameras, such as streak cameras and traveling-wave gated framing cameras. To ensure measurement accuracy, the time characteristics of the cameras need to be precisely calibrated. Existing calibration methods mainly include spatial sampling based on equal-arithmetic fiber bundles, microstrip transmission velocity measurement based on a combination of uniform spot irradiation and time-domain reflectometry, direct measurement using sub-picosecond X-ray pulses, and methods using Fabry-Perot etalons to generate known delayed light sequences.

[0003] However, existing methods generally suffer from limitations in calibration accuracy and efficiency. Specifically, the fiber bundle method is constrained by processing precision, spot spatial uniformity, and multimode dispersion; the direct irradiation method is affected by uneven light intensity distribution, gain attenuation, and transmission speed measurement errors introduced by non-ideal gating pulse sources; calibration methods based on ultrashort pulse sources are limited by the non-ideal nature of the pulses themselves and the complexity of the equipment; and the optical delay line method struggles to balance high resolution and simplicity. These factors collectively lead to complex traditional calibration processes with significant uncertainties, making it difficult to achieve high-precision, high-efficiency time characteristic calibration and meet the ever-increasing performance verification requirements of ultra-high time resolution cameras. Summary of the Invention

[0004] To improve the accuracy and efficiency of camera time characteristic calibration, this invention provides a device and method for detecting the time characteristics of an ultra-high time resolution camera, the specific technical solution of which is as follows:

[0005] The first aspect of the present invention provides a time characteristic detection device for an ultra-high time resolution camera, comprising: A laser source used to generate pulsed laser light; A polarization modulation element is disposed in the output optical path of the laser source and is used to modulate the pulsed laser into circularly polarized light; A beam splitter is disposed in the output light path of the polarization modulation element to decompose the circularly polarized light into a first linearly polarized beam and a second linearly polarized beam. The first optical path unit is used to guide the first linearly polarized beam along a fixed optical path to the cylindrical optical element; The second optical path unit is used to adjust the optical path of the second linearly polarized beam and guide it to the cylindrical optical element; The cylindrical optical element is used to receive the first linearly polarized beam and the second linearly polarized beam, and project them onto the imaging surface of the camera under test to form two spatially separated light spots.

[0006] Furthermore, the laser source is a femtosecond laser.

[0007] Furthermore, the beam splitter is a polarizing beam splitter, used to transmit linearly polarized light with vibration direction parallel to the incident surface to form the first linearly polarized beam, and to reflect linearly polarized light with vibration direction perpendicular to the incident surface to form the second linearly polarized beam.

[0008] Furthermore, the first optical path unit includes a first reflector and a second reflector. The first reflector receives a first linearly polarized beam and reflects it to the second reflector. The second reflector directs the first linearly polarized beam into the curvature direction of the cylindrical optical element in a vertical direction.

[0009] Furthermore, the second optical path unit includes a fixed reflector group, an adjustable reflector group, and an exit reflector arranged sequentially along the optical path; the adjustable reflector group is mounted on an optical path adjustment device, which is used to translate the adjustable reflector group along a direction parallel to the beam propagation direction; the second linearly polarized beam is guided to the cylindrical optical element sequentially through the fixed reflector group, the adjustable reflector group, and the exit reflector.

[0010] Furthermore, the fixed reflector group includes at least two third reflectors for changing the propagation direction of the second linearly polarized beam and guiding it to the adjustable reflector group.

[0011] Furthermore, the adjustable reflector assembly includes two fourth reflectors, the reflecting surfaces of which are at a 90° angle to each other.

[0012] Furthermore, the cylindrical optical element is a cylindrical mirror, and the curvature direction of the cylindrical mirror is perpendicular to the direction in which the first linearly polarized beam and the second linearly polarized beam are incident on the cylindrical mirror.

[0013] Furthermore, the two spatially separated light spots are elongated and parallel in length direction, and the light intensity distribution of the light spots is Gaussian.

[0014] The second aspect of the present invention provides a method for detecting the time characteristics of an ultra-high time resolution camera, used in the ultra-high time resolution camera time characteristic detection device described in the first aspect of the present invention, the method comprising: Generate a pulsed laser beam and modulate it into circularly polarized light; The circularly polarized light is decomposed into a first linearly polarized beam and a second linearly polarized beam that are orthogonal to each other using a beam splitter. By adjusting the second optical path unit, the optical path of the second linearly polarized beam is changed, so that a preset optical path difference is generated between it and the first linearly polarized beam; A first linearly polarized beam and a second linearly polarized beam with a preset optical path difference are projected onto the imaging surface of the camera under test through a cylindrical optical element, forming two spatially separated light spots; The gating time characteristics of the camera under test are determined based on the correspondence between the spatial position difference of the two light spots on the imaging plane and the optical path difference.

[0015] The present invention has the following beneficial effects: The present invention provides a device and method for detecting the time characteristics of an ultra-high time resolution camera. This device uses a polarization modulation element and a beam splitter to decompose a pulsed laser into two beams with defined polarization states. The two beams are guided to a cylindrical optical element by a differential design: a first optical path unit with a fixed optical path and a second optical path unit with an adjustable optical path. Under the action of the cylindrical optical element, two spatially separated light spots are formed on the camera's imaging surface. The device introduces a controllable optical path difference by adjusting the second optical path unit, generating a known and variable delay in the time dimension. This linearly maps the time information to the spatial position difference of the light spots, eliminating the need for complex external delay devices or idealized pulse sources for time characteristic calibration. Accurate characterization of time characteristics can be achieved through the direct correlation between the optical path difference of the two beams and the spatial distribution of the light spots, avoiding systematic errors introduced by factors such as uneven spatial distribution of light intensity, gain attenuation, pulse non-ideality, and inaccurate transmission speed measurement in traditional methods. This simplifies the calibration process and solves the problems of complex optical paths, cumbersome adjustments, and long processing times associated with traditional calibration methods. Attached Figure Description

[0016] The above and other objects, features, and advantages of the present invention will become more apparent from the more detailed description of the embodiments of the invention in conjunction with the accompanying drawings. The drawings are provided to further illustrate the embodiments of the invention and form part of the specification. They are used together with the embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings, the same reference numerals generally represent the same parts or steps.

[0017] Figure 1 This is a schematic diagram of the structure of a time characteristic detection device for an ultra-high time resolution camera provided in an exemplary embodiment of the present invention; Figure 2 This is a schematic flowchart of a method for detecting the temporal characteristics of an ultra-high temporal resolution camera provided in an exemplary embodiment of the present invention; Icons: 1-Laser source, 2-Polarization modulation element, 3-Beam splitter, 4-Cylindrical optical element, 5-First reflecting mirror, 6-Second reflecting mirror, 7-Third reflecting mirror, 8-Fourth reflecting mirror, 9-Outgoing reflecting mirror, 10-Optical path adjustment device. Detailed Implementation

[0018] The present invention will be further described below with reference to the embodiments shown in the accompanying drawings. Obviously, the described embodiments are merely some embodiments of the present invention, and not all embodiments of the present invention. It should be understood that the present invention is not limited to the exemplary embodiments described herein.

[0019] It should be noted that, unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps described in these embodiments do not limit the scope of the invention.

[0020] Those skilled in the art will understand that the terms "first," "second," etc., in the embodiments of the present invention are only used to distinguish different steps, devices, or modules, and do not represent any specific technical meaning, nor do they indicate a necessary logical order between them.

[0021] It should also be understood that in the embodiments of the present invention, "multiple" can refer to two or more, and "at least one" can refer to one, two or more.

[0022] It should also be understood that any component, data or structure mentioned in the embodiments of the present invention can generally be understood as one or more unless explicitly defined or given contrary instructions in the context.

[0023] Furthermore, the term "and / or" in this invention is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, the character " / " in this invention generally indicates that the preceding and following related objects have an "or" relationship.

[0024] It should also be understood that the description of the various embodiments in this invention emphasizes the differences between the various embodiments, and the similarities or similarities can be referred to each other. For the sake of brevity, they will not be described in detail.

[0025] At the same time, it should be understood that, for ease of description, the dimensions of the various parts shown in the accompanying drawings are not drawn according to actual scale.

[0026] The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the invention or its application or use.

[0027] Techniques, methods, and equipment known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and equipment should be considered part of the specification.

[0028] It should be noted that similar labels and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be discussed further in subsequent figures.

[0029] Example 1 Figure 1 This is a schematic diagram of the structure of a time characteristic detection device for an ultra-high time resolution camera provided in an exemplary embodiment of the present invention.

[0030] Specifically, refer to Figure 1 A time characteristic detection device for an ultra-high time resolution camera, comprising: Laser source 1 is used to generate pulsed laser; laser source 1 is a femtosecond laser.

[0031] Polarization modulation element 2 is disposed in the output optical path of laser source 1 and is used to modulate the pulsed laser into circularly polarized light; Beam splitter 3 is disposed in the output light path of the polarization modulation element 2 and is used to decompose the circularly polarized light into a first linearly polarized beam and a second linearly polarized beam. The first optical path unit is used to guide the first linearly polarized beam along a fixed optical path to the cylindrical optical element 4; The second optical path unit is used to adjust the optical path of the second linearly polarized beam and guide it to the cylindrical optical element 4; The cylindrical optical element 4 is used to receive the first linearly polarized beam and the second linearly polarized beam, and project them onto the imaging surface of the camera under test to form two spatially separated light spots.

[0032] In this system, a femtosecond laser, acting as laser source 1, emits an ultrashort pulse laser beam. This pulse laser is first incident on a polarization modulation element 2 and modulated into circularly polarized light. The circularly polarized light then incident on a beam splitter 3 to form a first linearly polarized beam and a second linearly polarized beam. The first linearly polarized beam is redirected by a fixed optical path unit consisting of two mirrors and finally incident on a cylindrical mirror at an angle perpendicular to its curvature. The second linearly polarized beam first passes through a fixed mirror group containing two mirrors to change its propagation direction, and then enters an adjustable mirror group driven by an optical path adjustment device 10. This adjustable mirror group consists of two mirrors with their reflective surfaces at a 90-degree angle to each other. It is moved along the direction parallel to the beam propagation by a precision one-dimensional translation stage, thereby achieving continuous adjustment of the optical path of the second linearly polarized beam. After optical path adjustment, the beam then passes through an exit mirror 9 and is incident on the cylindrical mirror at an angle perpendicular to its curvature. A cylindrical mirror directs two incident beams of light onto the imaging plane (microstrip) of either the framing camera or the streak camera under test, forming two parallel, Gaussian-distributed stripes of light. Due to a controllable optical path difference determined by the position of the adjustable mirror assembly, the two beams arrive at the imaging plane at different times. This causes a shift in the position of the imaging plane activated by the camera's gating pulse, resulting in spatial separation of the peak values ​​of the two light spots. By altering the optical path difference using a precision translation stage, a linear calibration relationship between time delay and spatial shift can be established, allowing for the calculation of key parameters such as the camera's gating time or temporal resolution.

[0033] As described above, the ultra-high time resolution camera time characteristic detection device and method provided by the present invention decomposes a pulsed laser into two beams with defined polarization states using a polarization modulation element 2 and a beam splitter 3. The two beams are guided to a cylindrical optical element 4 by a differential design of a first optical path unit with a fixed optical path and a second optical path unit with an adjustable optical path. Under the action of the cylindrical optical element 4, two spatially separated light spots are formed on the camera imaging surface. This device introduces a controllable optical path difference through the second optical path unit, thereby generating a known and variable delay in the time dimension. The time information is linearly mapped to the spatial position difference of the light spots, so that the calibration of time characteristics does not rely on complex external delay devices or idealized pulse sources. Accurate characterization of time characteristics can be achieved through the direct correlation between the optical path difference of the two beams and the spatial distribution of the light spots, avoiding the systematic errors introduced by factors such as uneven spatial distribution of light intensity, gain attenuation, pulse non-ideality, and inaccurate measurement of transmission speed in traditional methods. This simplifies the calibration process and solves the problems of complex optical paths, cumbersome adjustments, and long time consumption in traditional calibration methods.

[0034] Example 2 Based on Embodiment 1 above, as an optional implementation, the beam splitter 3 is a polarizing beam splitter, used to transmit linearly polarized light with vibration direction parallel to the incident plane to form the first linearly polarized beam, and to reflect linearly polarized light with vibration direction perpendicular to the incident plane to form the second linearly polarized beam. In this embodiment, the circularly polarized light generated by the polarization modulation element 2, containing linearly polarized light components with vibration direction parallel to the incident plane of the polarizing beam splitter, will be completely transmitted through the lens to form the first linearly polarized beam; while the linearly polarized light components with vibration direction perpendicular to the incident plane will be efficiently reflected by the dielectric film interface of the lens to form the second linearly polarized beam. Through this physical process, a beam of circularly polarized light is spatially separated strictly according to orthogonal linear polarization states.

[0035] Example 3 Based on Embodiments 1 and 2 above, as an optional implementation, the first optical path unit includes a first reflecting mirror 5 and a second reflecting mirror 6. The first reflecting mirror 5 receives a first linearly polarized beam and reflects it to the second reflecting mirror 6. The second reflecting mirror 6 incident the first linearly polarized beam vertically onto the curvature direction of the cylindrical optical element 4. The first linearly polarized beam transmitted from the polarizing beam splitter first incident on the first reflecting mirror 5. The mirror surface of the first reflecting mirror 5 is placed at a specific angle, reflecting the incident first linearly polarized beam towards the second reflecting mirror 6. The second reflecting mirror 6 receives the beam from the first reflecting mirror 5 and reflects it again, ultimately adjusting the propagation direction of the first linearly polarized beam to be perpendicular to the curvature direction of the cylindrical optical element 4.

[0036] Example 4 Based on the above embodiments 1, 2, and 3, as an optional implementation, the second optical path unit includes a fixed mirror group, an adjustable mirror group, and an exit mirror 9 arranged sequentially along the optical path; the adjustable mirror group is mounted on an optical path adjustment device 10, which is used to translate the adjustable mirror group parallel to the beam propagation direction; the second linearly polarized beam is guided to the cylindrical optical element 4 sequentially through the fixed mirror group, the adjustable mirror group, and the exit mirror 9. Specifically, the optical path of the second beam is adjusted by the optical path adjustment device 10, so that the second beam produces at least two different optical path differences relative to the first beam; wherein the optical path of the second beam passes through two mirrors mounted on a precision one-dimensional translation stage, and adjusting the position s of the translation stage can change the optical path of the second beam, that is, change the time interval between the first beam and the second beam reaching the imaging surface. It should be noted that the refraction methods of the two laser beams are not unique, and the specific number of lenses in the fixed reflector group can be adjusted according to the actual spatial layout. The key is to reliably guide the beam to the adjustable reflector group. The method for adjusting the optical path of the second linearly polarized beam is not unique; a precision one-dimensional translation stage can be used, or it can be adjusted manually. The optical path arrangement and adjustment principle described in this embodiment are generally applicable to various ultra-high time resolution cameras that require time characteristic calibration, including but not limited to traveling wave gated framing cameras and streak cameras.

[0037] This embodiment modularizes the second optical path unit into three parts: steering, adjustment, and orientation. This transforms the complex time difference generation into a simple mechanical displacement measurement, making the calibration process not only intuitive and easy to operate, but also avoiding the uncertainties introduced by electronic delay or complex optical interference in existing methods.

[0038] Example 5 Based on the above embodiments 1, 2, 3, and 4, as an optional implementation, the fixed reflector group includes at least two third reflectors 7, used to change the propagation direction of the second linearly polarized beam and guide it to the adjustable reflector group. The adjustable reflector group includes two fourth reflectors 8, with the reflecting surfaces of the two fourth reflectors 8 forming a 90° angle with each other. The second linearly polarized beam incident on the adjustable reflector group is reflected sequentially on the two reflecting surfaces. Since the angle between the reflecting surfaces is 90 degrees, and they are usually configured such that the incident light forms a 45-degree angle with each reflecting surface, the beam's exit direction will be parallel to the incident direction after two reflections. When the optical path adjustment device 10 drives the module to translate along a direction parallel to the incident direction of the beam, the geometric path length of the beam inside the module will change linearly, thereby achieving adjustment of the optical path of the second linearly polarized beam.

[0039] Example 6 Based on the above embodiments 1, 2, 3, 4, and 5, as an optional implementation, the cylindrical optical element 4 is a cylindrical mirror, and the curvature direction of the cylindrical mirror is perpendicular to the direction in which the first linearly polarized beam and the second linearly polarized beam are incident on the cylindrical mirror. The direction of the cylindrical generatrix of the cylindrical mirror, that is, the direction in which it has curvature, is perpendicular to the propagation direction when the first linearly polarized beam and the second linearly polarized beam are finally incident on the surface of the cylindrical mirror. To achieve this condition, during the device assembly and adjustment process, the angles of the second reflecting mirror 6 at the end of the first optical path unit and the exiting reflecting mirror 9 at the end of the second optical path unit need to be adjusted so that the two parallel beams from different paths are both incident on the curvature surface of the cylindrical mirror at a 90-degree angle. The cylindrical mirror only diverges the beam in its curvature direction. After each incident parallel beam passes through this cylindrical mirror, it will form a thin, elongated line-shaped light spot with a Gaussian intensity distribution on the imaging surface of the camera under test, and the length directions of the two light spots remain parallel to each other because the incident beams are parallel.

[0040] Example 7 Based on the above embodiments 1, 2, 3, 4, 5 and 6, as an optional implementation, the two spatially separated light spots are elongated and parallel in length direction, and the light intensity distribution of the light spots is Gaussian.

[0041] In this embodiment, due to the optical path difference between the first and second linearly polarized beams, their arrival times at the imaging surface differ, causing a shift in the position of the imaging surface activated by the gating pulse. Ultimately, two elongated light spots with parallel lengths and staggered peak positions appear on the imaging surface, both conforming to a Gaussian intensity distribution. The peak spacing between the two light spots is positively correlated with the optical path difference between the two beams. By analyzing the spatial distribution characteristics of the light intensity, the gating time characteristics of the ultra-high time resolution camera can be characterized. A controllable optical path difference is introduced in the second optical path unit, causing the second linearly polarized beam to arrive at the imaging surface with a predetermined delay relative to the first linearly polarized beam. For a traveling-wave gating framing camera, this time difference causes the activation times of different positions on the imaging surface by the gating pulse within the camera to match the arrival times of the two beams, thus recording the two light signals at different spatial positions on the imaging surface. The final result is that the acquired image shows two elongated light spots with parallel lengths but spatially staggered peak intensity positions. The spatial spacing between the peak points of the two light spots has a linear relationship with the optical path difference introduced between the two beams. By extracting the peak positions of two Gaussian-distributed light spots and calculating their distance using image processing algorithms, and combining this with known light speed and system geometric parameters, key temporal characteristic parameters such as the gating time window width or temporal resolution of the camera under test can be calculated. This measurement method, based on the analysis of spatial light intensity distribution, transforms the calibration of temporal characteristics into the measurement of high signal-to-noise ratio features in static images. It is not only intuitive and easy to operate, but also fundamentally avoids errors caused by pulse timing jitter, electronic response delays, or instabilities in existing dynamic measurement methods.

[0042] Example 8 It should be understood that the aforementioned embodiments of the ultra-high time resolution camera time characteristic detection device can also be similarly applied to the following ultra-high time resolution camera time characteristic detection method for similar extensions. For simplicity, it is not described in detail.

[0043] Figure 2 This is a schematic flowchart of a method for detecting the temporal characteristics of an ultra-high temporal resolution camera provided in an exemplary embodiment of the present invention. The method can be executed on a server (e.g., a cloud service platform, a locally deployed server), and includes: Step 100: Generate a pulsed laser beam and modulate it into circularly polarized light; specifically, this is done by activating a femtosecond laser to generate an ultrashort pulsed laser beam. The pulsed laser is then guided to the incident polarization modulation element 2, and the angle between the optical axis of the waveplate and the laser polarization direction is adjusted to 45° to modulate the linearly polarized pulsed laser into circularly polarized light.

[0044] Step 200: Use beam splitter 3 to decompose the circularly polarized light into a first linearly polarized beam and a second linearly polarized beam that are orthogonal to each other; the circularly polarized light generated in step 100 is incident on the polarizing beam splitter, which transmits the linearly polarized light component whose vibration direction is parallel to its incident surface to form the first linearly polarized beam; at the same time, it reflects the linearly polarized light component whose vibration direction is perpendicular to the incident surface to form the second linearly polarized beam.

[0045] Step 300: By adjusting the second optical path unit, the optical path of the second linearly polarized beam is changed, creating a preset optical path difference between it and the first linearly polarized beam. Specifically, the optical path adjustment device 10 is operated, for example, by driving a precision one-dimensional translation stage, which moves the adjustable mirror assembly mounted on it along a direction parallel to the beam propagation direction. Since the adjustable mirror assembly consists of two mirrors with their reflective surfaces at a specific angle to each other, its translation linearly changes the geometric path length of the second linearly polarized beam within the module, thereby continuously adjusting its total optical path. By positioning the translation stage to a specific position, a known preset optical path difference relative to the fixed optical path of the first linearly polarized beam can be set for the second linearly polarized beam.

[0046] Step 400: A first linearly polarized beam and a second linearly polarized beam with a preset optical path difference are projected onto the imaging surface of the camera under test via cylindrical optical element 4, forming two spatially separated light spots. The first linearly polarized beam is guided through a fixed optical path composed of mirrors, and the second linearly polarized beam is guided through an optical path including a fixed mirror group, an adjustable mirror group that has been adjusted, and an exit mirror 9, respectively, to the cylindrical mirror, ensuring that both beams are incident perpendicularly to the curvature direction of the cylindrical mirror. The cylindrical mirror spreads the two parallel beams on its focal plane, forming two long strip-shaped light spots with parallel length directions, Gaussian intensity distribution, and spatially separated positions on the imaging surface of the camera under test.

[0047] Step 500: Determine the gating time characteristics of the camera under test based on the correspondence between the spatial position difference of the two light spots on the imaging surface and the optical path difference. Extract the peak intensity pixel positions of each Gaussian distributed light spot using image processing algorithms. Calculate the spatial distance between the two peak positions; this distance has a linear proportional relationship with the preset optical path difference introduced in Step 300, with the proportionality coefficient determined by the speed of light and the system's geometric magnification. Using this relationship, convert the measured spatial position difference into the actual time difference between the two beams reaching the imaging surface. Combined with the camera's working principle, this time difference can be used to calculate the camera's gating time window, temporal resolution, and other temporal characteristic parameters.

[0048] In some embodiments, a technique is employed where a dual-beam irradiation imaging surface with adjustable optical path is used to acquire static and dynamic spot images. Taking a framing camera as an example, spatial intensity correction is performed on the dynamic image using the static image under DC voltage. This effectively suppresses the influence of non-uniformity in the spatial distribution of the laser spot on the calibration results, thereby improving the accuracy of the gain attenuation curve fitting data without the need for additional inter-shot energy monitoring. The dynamic image is the spot image acquired by the framing camera under at least two different optical paths when the first linearly polarized beam and the second linearly polarized beam are driven by a gating pulse and synchronized with the pulsed laser. Simultaneously, multiple frames of images are acquired based on the variable optical path, and the gating pulse transmission speed, the fitted gain attenuation curve, and the final exposure time are calculated using these images. This avoids the complex calibration process that requires multiple discrete steps in existing technologies. This calibration method can be completed in a single continuous operation, improving calibration efficiency. By eliminating non-uniformity interference through spatial correction and combining it with its own optical path difference velocimetry, this method retains the high quantization accuracy advantage of the direct irradiation method while overcoming the technical problems of gain attenuation modulation and inaccurate pulse velocity measurement in existing methods. This enables higher-precision calibration of the exposure time and gain attenuation characteristics of framing cameras.

[0049] The basic principles of the present invention have been described above with reference to specific embodiments. However, it should be noted that the advantages, benefits, and effects mentioned in the present invention are merely examples and not limitations, and should not be considered as essential features of each embodiment of the present invention. Furthermore, the specific details of the invention described above are for illustrative and facilitative purposes only, and are not limitations. These details do not limit the present invention to the necessity of employing the specific details described above.

[0050] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For system embodiments, since they largely correspond to method embodiments, the description is relatively simple; relevant parts can be referred to the descriptions in the method embodiments.

[0051] The block diagrams of devices, apparatuses, devices, and systems involved in this invention are merely illustrative examples and are not intended to require or imply that they must be connected, arranged, or configured in the manner shown in the block diagrams. As those skilled in the art will recognize, these devices, apparatuses, devices, and systems can be connected, arranged, and configured in any manner. Words such as “comprising,” “including,” “having,” etc., are open-ended terms meaning “including but not limited to,” and are used interchangeably with them. The terms “or” and “and” as used herein refer to the terms “and / or,” and are used interchangeably with them unless the context clearly indicates otherwise. The term “such as” as used herein refers to the phrase “such as but not limited to,” and is used interchangeably with it.

[0052] The methods and apparatus of the present invention may be implemented in many ways. For example, they may be implemented by software, hardware, firmware, or any combination of software, hardware, and firmware. The above-described order of steps for the methods is for illustrative purposes only, and the steps of the methods of the present invention are not limited to the order specifically described above unless otherwise specifically stated. Furthermore, in some embodiments, the present invention may also be implemented as a program recorded on a recording medium, the program comprising machine-readable instructions for implementing the methods according to the present invention. Thus, the present invention also covers recording media storing programs for performing the methods according to the present invention.

[0053] It should also be noted that in the apparatus, device, and method of the present invention, the components or steps can be disassembled and / or recombined. These disassemblies and / or recombinations should be considered as equivalent solutions of the present invention.

[0054] The above description of aspects of the invention is provided to enable any person skilled in the art to make or use the invention. Various modifications to these aspects will be readily apparent to those skilled in the art, and the general principles defined herein can be applied to other aspects without departing from the scope of the invention. Therefore, the invention is not intended to be limited to the aspects shown herein, but rather to be carried out within the widest scope consistent with the principles and novel features of the invention herein.

[0055] The above description has been given for purposes of illustration and description. Furthermore, this description is not intended to limit the embodiments of the invention to the forms described herein. Although numerous exemplary aspects and embodiments have been discussed above, those skilled in the art will recognize certain variations, modifications, alterations, additions, and sub-combinations thereof.

[0056] It should be noted that the order of the above embodiments of the present invention is merely for descriptive purposes and does not represent the superiority or inferiority of the embodiments. The processes depicted in the accompanying drawings do not necessarily require a specific or sequential order to achieve the desired result. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0057] The various embodiments in this specification are described in a progressive manner. The same or similar parts between the various embodiments can be referred to each other. Each embodiment focuses on describing the differences from other embodiments.

Claims

1. A time characteristic detection device for an ultra-high time resolution camera, characterized in that, include: A laser source used to generate pulsed laser light; A polarization modulation element is disposed in the output optical path of the laser source and is used to modulate the pulsed laser into circularly polarized light; A beam splitter is disposed in the output light path of the polarization modulation element to decompose the circularly polarized light into a first linearly polarized beam and a second linearly polarized beam. The first optical path unit is used to guide the first linearly polarized beam along a fixed optical path to the cylindrical optical element; The second optical path unit is used to adjust the optical path of the second linearly polarized beam and guide it to the cylindrical optical element; The cylindrical optical element is used to receive the first linearly polarized beam and the second linearly polarized beam, and project them onto the imaging surface of the camera under test to form two spatially separated light spots.

2. The ultra-high time resolution camera time characteristic detection device as described in claim 1, characterized in that, The laser source is a femtosecond laser.

3. The ultra-high time resolution camera time characteristic detection device as described in claim 1, characterized in that, The beam splitter is a polarizing beam splitter, used to transmit linearly polarized light with vibration direction parallel to the incident surface to form the first linearly polarized beam, and to reflect linearly polarized light with vibration direction perpendicular to the incident surface to form the second linearly polarized beam.

4. The ultra-high time resolution camera time characteristic detection device as described in claim 1, characterized in that, The first optical path unit includes a first reflector and a second reflector. The first reflector receives a first linearly polarized beam and reflects it to the second reflector. The second reflector directs the first linearly polarized beam into the curvature direction of the cylindrical optical element in a vertical direction.

5. The ultra-high time resolution camera time characteristic detection device as described in claim 1, characterized in that, The second optical path unit includes a fixed reflector group, an adjustable reflector group, and an exit reflector arranged sequentially along the optical path; the adjustable reflector group is mounted on an optical path adjustment device, which is used to translate the adjustable reflector group along a direction parallel to the beam propagation direction; the second linearly polarized beam is guided to the cylindrical optical element sequentially through the fixed reflector group, the adjustable reflector group, and the exit reflector.

6. The ultra-high time resolution camera time characteristic detection device as described in claim 5, characterized in that, The fixed mirror assembly includes at least two third mirrors for changing the propagation direction of the second linearly polarized beam and guiding it to the adjustable mirror assembly.

7. The ultra-high time resolution camera time characteristic detection device as described in claim 6, characterized in that, The adjustable reflector assembly includes two fourth reflectors, the reflecting surfaces of which are at a 90° angle to each other.

8. The ultra-high time resolution camera time characteristic detection device as described in claim 1, characterized in that, The cylindrical optical element is a cylindrical mirror, and the curvature direction of the cylindrical mirror is perpendicular to the direction in which the first linearly polarized beam and the second linearly polarized beam are incident on the cylindrical mirror.

9. The ultra-high time resolution camera time characteristic detection device as described in any one of claims 1 to 8, characterized in that, The two spatially separated light spots are elongated and parallel in length direction, and the light intensity distribution of the light spots is Gaussian.

10. A method for detecting the temporal characteristics of an ultra-high time resolution camera, characterized in that, The method for the ultra-high time resolution camera time characteristic detection apparatus according to any one of claims 1 to 9 includes: Generate a pulsed laser beam and modulate it into circularly polarized light; The circularly polarized light is decomposed into a first linearly polarized beam and a second linearly polarized beam that are orthogonal to each other using a beam splitter. By adjusting the second optical path unit, the optical path of the second linearly polarized beam is changed, so that a preset optical path difference is generated between it and the first linearly polarized beam; A first linearly polarized beam and a second linearly polarized beam with a preset optical path difference are projected onto the imaging surface of the camera under test through a cylindrical optical element, forming two spatially separated light spots; The gating time characteristics of the camera under test are determined based on the correspondence between the spatial position difference of the two light spots on the imaging plane and the optical path difference.

Images