Framing imaging device and framing imaging system

Abstract

The embodiment of the present application relates to the technical field of ultra-high-speed imaging, and discloses a framing imaging device, which comprises a chirp spreading element, a diffraction element, a first Fourier lens, a framing element and a second Fourier lens, wherein the chirp spreading element is used for spreading incident light and emitting chirp pulse light; the diffraction element is used for splitting the chirp pulse light into diffraction beams propagating in different directions; the first Fourier lens is used for emitting the incident diffraction beams into central-symmetrical array beams; the framing element is used for framing the array beams into delay beams; and the second Fourier lens is used for converging the delay beams to the same illumination area. The present application also discloses a framing imaging system. The present application solves the technical problem of how to simplify the structure of a conventional framing imaging device under the premise of the same time resolution.

Description

Technical Field

[0001] This application relates to the field of ultra-high-speed imaging technology. More specifically, this application relates to a framing imaging device and a framing imaging system. Background Technology

[0002] Atomic time (10) -12 ~10 -15 Temporal framing technology, which enables dynamic processes at the s) scale, is an ultra-high-speed imaging technique for single-exposure imaging. Traditional framing imaging devices capable of achieving ultra-high-speed imaging include, for example, an invention patent with publication number CN102841498B, which discloses an ultra-fast framing imaging device comprising a chirped pulse light generating device, a beam splitter, and a camera array. Because this imaging device images different wavelength components of the chirped pulse light separated by the beam splitter using a camera array—that is, one camera for each wavelength—the device has a complex structure and a large size. Summary of the Invention

[0003] One objective of this application is to solve the above-mentioned problems and provide corresponding beneficial effects.

[0004] Another objective of this application is to provide a framing imaging device and a framing imaging system, which at least solves the technical problem of simplifying the structure of a traditional framing imaging device while maintaining the same temporal resolution. This is mainly achieved through the technical solutions in the following aspects:

[0005] <First aspect of the embodiments of this application>

[0006] The first aspect of this application provides a framing imaging device, comprising:

[0007] A chirp broadening element is used to broaden incident light and output chirped pulsed light.

[0008] A diffraction element for splitting the chirped pulse light into diffraction beams that propagate in different directions;

[0009] A first Fourier lens is used to output the incident diffracted beam as a centrally symmetric array beam.

[0010] Amplification elements are used to divide the array beam into delayed beams; and

[0011] A second Fourier lens is used to converge the delayed beam onto the same illumination area.

[0012] In some technical solutions, the chirp broadening element is configured as a dispersive element.

[0013] In some technical solutions, the dispersive element is selected from one of a grating pair, a glass column, or an optical fiber.

[0014] In some technical solutions, the diffraction element is disposed at the front focal plane of the first Fourier lens.

[0015] In some technical solutions, the framing element is disposed at the rear focal plane of the first Fourier lens.

[0016] In some technical solutions, the framing element is located at the front focal plane of the second Fourier lens.

[0017] In some technical solutions, the gradation element is configured as an aperture array.

[0018] In some technical solutions, the amplitude-splitting element is configured as a filter array.

[0019] In some technical solutions, the illumination area is located at the back focal plane of the second Fourier lens.

[0020] In some technical solutions, the delayed beam, after passing through the second Fourier lens, interferes at the rear focal plane of the second Fourier lens, forming interference fringes.

[0021] In some technical solutions, the first Fourier lens and the second Fourier lens form a 4f system.

[0022] <Second aspect of the embodiments of this application>

[0023] A second aspect of this application provides a framing imaging system, comprising:

[0024] The first aspect of this application provides a light source structure, a framing imaging device, and an imaging structure, wherein the framing imaging device forms an illumination area based on the light source emitted from the light source structure, and the imaging structure images an object located in the illumination area.

[0025] In some technical solutions, the light source structure includes a pulsed laser and a beam expander and collimator, wherein the pulsed laser is used to generate a laser source, and the beam expander and collimator is used to collimate the laser source into the incident light of the framing imaging device.

[0026] In some technical solutions, the imaging structure includes a detector and at least one lens, wherein the at least one lens is used to image the object onto the image plane of the detector, and the detector is used to acquire the image of the image plane and transmit it to an external electronic device.

[0027] The embodiments of this application have the following beneficial effects:

[0028] In existing technologies, camera arrays are used to image chirped pulses of different wavelengths separately. This means that existing technologies have multiple illumination areas, each corresponding to one camera in the array. Therefore, existing technologies require separate imaging of different wavelength components of the chirped pulses in different illumination areas. In stark contrast, the embodiments of this application, by placing a first Fourier lens, a framing element, and a second Fourier lens after the diffraction element, enable the diffracted beam to ultimately illuminate the same illumination area after framing delay. Based on this, this application can image different wavelength components of the chirped pulses separately in the same illumination area, meaning only one imager (e.g., one camera) is needed. Therefore, this application simplifies the structure of traditional framing imaging devices while maintaining the same temporal resolution, thereby reducing the size of traditional framing imaging devices.

[0029] In some technical solutions, the diffraction element and the 4f system are integrated to achieve the framing structure, thereby miniaturizing and integrating the framing imaging device.

[0030] This application employs a combination of diffraction elements and a 4f system, which can achieve illumination areas of various field-of-view sizes. Therefore, it can be applied to various fields of view, solving the problem of limited field of view in traditional framing imaging devices.

[0031] In some technical solutions, the framing imaging system of this application includes a light source structure, a framing imaging device provided in the first aspect of this application, and an imaging structure, so that the time delay structure (i.e., the framing imaging device) and the imaging structure are independent of each other. Therefore, this application can replace the framing imaging device at any time, thereby solving the problem of small or difficult-to-adjust time delay modulation range.

[0032] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0033] The various features and embodiments of the invention mentioned in the foregoing aspects may be applied to other aspects as appropriate. Therefore, a specific feature in one aspect may be appropriately combined with specific features in other aspects.

[0034] Other advantages, objectives and features of the present invention will become apparent in part from the following description, and in part from those skilled in the art through study and practice of the invention. Attached Figure Description

[0035] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the description of the embodiments of this application will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0036] Figure 1 This is a schematic diagram of the structure of the framing imaging device of the present invention in some embodiments;

[0037] Figure 2 This is a pulse width diagram of the incident light in some embodiments of the present invention;

[0038] Figure 3 This is a pulse width diagram of the chirped pulse light of the present invention in some embodiments;

[0039] Figure 4 This is a schematic diagram of the optical field of the array beam in some embodiments of the present invention;

[0040] Figure 5 This is a pulse width diagram of the spectrum in the illumination region in this invention;

[0041] Figure 6 This is a schematic diagram of the optical field of the aperture array of the present invention in some embodiments;

[0042] Figure 7 This is a schematic diagram of the optical field of the filter array of the present invention in some embodiments;

[0043] Figure 8 This is a schematic diagram illustrating the image restoration principle of the striped pattern in some embodiments of the present invention;

[0044] Figure 9 This is a schematic diagram of the framing imaging system of the present invention in some embodiments;

[0045] Figure 10 This is a schematic diagram of the framing imaging system of the present invention in some other embodiments;

[0046] Figure 11 This is a schematic diagram of the illumination area and imaging structure of the present invention in some embodiments;

[0047] Figure 12 This is a schematic diagram of the light source structure of the present invention in some embodiments;

[0048] Figure 13 This is a schematic diagram illustrating the image restoration principle of the detector in some embodiments of the present invention;

[0049] Explanation of icon numbers:

[0050] 10. Framing imaging device; 11. Chirped broadening element; 12. Diffraction element; 13. First Fourier lens; 14. Framing element; 15. Second Fourier lens;

[0051] 20. Framing imaging system;

[0052] 21. Light source structure; 211. Pulsed laser; 212. Beam expander and collimator assembly;

[0053] 22. Imaging structure; 221. At least one lens; 222. Detector;

[0054] A. Lighting area;

[0055] L1, incident light; L2, chirped pulse light; L3, diffracted beam; L4, array beam; L5, delayed beam. Detailed Implementation

[0056] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0057] The terms "first" and "second," etc., used in the specification of embodiments of this application are used to distinguish different objects, rather than to describe a specific order of objects. For example, "first Fourier lens" and "second Fourier lens" are used to distinguish different Fourier lenses, rather than to describe a specific order of Fourier lenses.

[0058] In the embodiments of this application, the terms "exemplary" or "for example" are used to indicate that something is an example, illustration, or description. Any embodiment or design that is described as "exemplary" or "for example" in the embodiments of this application should not be construed as being more preferred or advantageous than other embodiments or designs. Specifically, the use of the terms "exemplary" or "for example" is intended to present the relevant concepts in a specific manner.

[0059] It should be noted that, in this document, the terms “comprising,” “including,” or any other variations thereof are intended to cover non-exclusive inclusion, for example, a process, method, system, product, or device that includes a series of steps or units is not necessarily limited to those steps or units that are explicitly listed, but may include other steps or units that are not explicitly listed or that are inherent to such process, method, product, or device.

[0060] The specific embodiments of this application will be further described below with reference to the accompanying drawings.

[0061] <Segmented Imaging Device>

[0062] like Figure 1 The diagram shown is a structural schematic of a framing imaging device 10 provided by the present invention. Figure 1 In the above, the framing imaging device 10 includes:

[0063] The chirped broadening element 11 is used to broaden the incident light L1 and the emitted chirped pulse light L2;

[0064] Diffraction element 12 is used to split the chirped pulse light L2 into diffraction beams L3 that propagate in different directions;

[0065] The first Fourier lens 13 is used to output the incident diffracted beam L3 into a centrally symmetric array beam L4.

[0066] Amplification element 14 is used to divide the array beam L4 into a delayed beam L5; and

[0067] A second Fourier lens 15 is used to converge the delayed beam L5 onto the same illumination area A.

[0068] In this embodiment, the chirp broadening element 11, the diffraction element 12, the first Fourier lens 13, the amplitude splitting element 14, and the second Fourier lens 15 are arranged sequentially along the same optical axis.

[0069] The incident light L1 is a femtosecond laser pulse. The pulse width of the incident light L1 is short, and all spectral components are located at the same time. The pulse width of the incident light L1 can be referenced... Figure 2 As shown.

[0070] The chirp broadening element 11 is configured as a dispersive element. The dispersive element is selected from one of the following: grating pair, glass column, prism pair, or optical fiber.

[0071] The incident light L1 is broadened by the chirped broadening element 11, and the chirped pulse light L2 is emitted. At this time, different spectra in the chirped pulse light L2 correspond to different times. The pulse width of the chirped pulse light L2 can be referenced... Figure 3 As shown, in Figure 3 In the diagram, λ1 represents the first spectrum, t1 represents the time corresponding to λ1, and λ n Let t represent the nth spectrum. n Represents λ n The corresponding time.

[0072] The diffraction element 12 is disposed at the front focal plane of the first Fourier lens 13. In this application, the increased image size can be achieved by using different diffraction elements 12 to split the beam. Based on this, this application can reduce the structural size and assembly difficulty without increasing the structural size.

[0073] The diffracted beam L3 exits through the first Fourier lens 13, forming an array beam L4 at the back focal plane of the first Fourier lens 13. The dot pattern of the array beam L4 is referenced... Figure 4 As shown. In Figure 4 In this context, because the array beam L4 is an ultrashort pulse, it contains multiple spectra (i.e., Figure 4 λ1-λ n Therefore, except for the central principal maximum, the point formed behind the first Fourier lens 13 is elongated along the central angular direction.

[0074] The amplitude-splitting element 14 divides the array beam L4 into a series of time-sequential sub-pulses, which are the delayed beam L5. The amplitude-splitting element 14 is located at the back focal plane of the first Fourier lens 13. The amplitude-splitting element 14 is also used to filter the array beam L4.

[0075] The framing element 14 is disposed at the front focal plane of the second Fourier lens 15.

[0076] The delayed beam L5 is converged to the illumination area A by the second Fourier lens 15, and the illumination area A is located at the back focal plane of the second Fourier lens 15.

[0077] The pulse width of the spectrum in the illumination region A is as follows: Figure 5 As shown. In Figure 5 In, λ1-λ n Representing different wavelengths, t1-t n Represents λ1-λ n The time corresponding to each wavelength.

[0078] In the above embodiments, this application provides a first Fourier lens 13, a framing element 14, and a second Fourier lens 15 after the diffraction element 12. This allows the diffracted beam L3 to be illuminated in the same illumination area A after framing delay. Based on this, this application can image different wavelength components of the chirped pulse light L2 separately in the same illumination area A, that is, only one imager (e.g., a camera) is needed. Therefore, this application can simplify the structure of the conventional framing imaging device 10 while maintaining the same time resolution, thereby reducing the size of the conventional framing imaging device 10.

[0079] In some embodiments, the amplitude-splitting element 14 is configured as an aperture array. By using the aperture array to filter the array beam L4, a centrally symmetrical beam L5 can be emitted, with each point forming a pair of delayed beams L5. A schematic diagram of the optical field of the aperture array is shown below. Figure 6 As shown. In Figure 6 In, λ1-λ n Representing different wavelengths.

[0080] In some embodiments, the amplitude-splitting element 14 is configured as a filter array. The filter array can be a narrowband filter array. It can also emit a centrally symmetrical beam, with the two points forming a pair of delayed beams L5. A schematic diagram of the optical field of the filter array is shown below. Figure 7 As shown. In Figure 7 In, λ1-λ n Representing different wavelengths.

[0081] In some embodiments, the delayed beam L5, after passing through the second Fourier lens 15, interferes at the back focal plane of the second Fourier lens 15, forming an interference fringe pattern, such as... Figure 8 As shown. In Figure 8 In, λ1-λ n Representing different wavelengths, t1-t n Represents λ1-λ n The time corresponding to each wavelength, that is, Figure 8 There are n wavelengths, each of which can form a set of interference fringes in different directions. The illumination light that forms the interference fringes illuminates a dynamic object, thus carrying information about the dynamic object.

[0082] The information of the dynamic object refers to the image of the illuminated object at a certain moment when it is illuminated.

[0083] The interference fringes are a transmittance distribution, and the transmittance distribution satisfies the following condition:

[0084]

[0085] Where T represents transmittance, x and y represent spatial positions, i represents the direction of the fringe, θ represents the angle of the fringe direction, f represents the frequency of the fringe (i.e. the number of fringe segments per unit length), and n represents the total number of fringe groups.

[0086] In some embodiments, the first Fourier lens 13 and the second Fourier lens 15 form a 4f system.

[0087] <Segmented Imaging System>

[0088] like Figure 9-12 The diagram shown is a structural schematic of a framing imaging system 20 provided in this application. Figure 9-12The framing imaging system 20 includes: a light source structure 21, a framing imaging device 10 and an imaging structure 22 provided in the first aspect of this application, wherein the framing imaging device 10 forms an illumination area A based on the light source emitted from the light source structure 21, and the imaging structure 22 images the object located in the illumination area A.

[0089] In some technical solutions, such as Figure 12 As shown, the light source structure 21 includes a pulsed laser 211 and a beam expander and collimator 212, wherein the pulsed laser 211 is used to generate a laser light source, and the beam expander and collimator 212 is used to collimate the laser light source into the incident light L1 of the framing imaging device 10.

[0090] In some technical solutions, such as Figure 11 As shown, the imaging structure 22 includes a detector 222 and at least one lens 221, wherein the at least one lens 221 is used to image the object on the image plane of the detector 222, and the detector 222 is used to acquire the image of the image plane and transmit it to an external electronic device.

[0091] The image of the image plane of the detector 222 is as follows Figure 8 As shown, this is a superimposed image of stripes at different angles carrying information about a dynamic object at all times. After Fourier transform, the image is obtained as follows: Figure 13 The image shown is in Figure 13 In the middle, t1-t n The time corresponding to each wavelength.

[0092] The above descriptions are examples of the best embodiments of this application, and the parts not described in detail are common knowledge to those skilled in the art. The scope of protection of this application is determined by the content of the claims, and any equivalent modifications made based on the technical teachings of this application are also within the scope of protection of this application.

Claims

1. A framing imaging device, characterized in that, include: A chirp broadening element is used to broaden incident light and output chirped pulsed light. A diffraction element for splitting the chirped pulse light into diffraction beams that propagate in different directions; A first Fourier lens is used to output the incident diffracted beam as a centrally symmetric array beam. Amplification elements are used to divide the array beam into delayed beams; and A second Fourier lens is used to converge the delayed beam onto the same illumination area. The diffraction element is disposed at the front focal plane of the first Fourier lens; The framing element is disposed at the rear focal plane of the first Fourier lens; The framing element is located at the front focal plane of the second Fourier lens; The illumination area is located at the back focal plane of the second Fourier lens. The delayed beam, after passing through the second Fourier lens, interferes at the back focal plane of the second Fourier lens, forming interference fringes.

2. The framing imaging device according to claim 1, characterized in that, The chirp broadening element is configured as a dispersive element.

3. The framing imaging device according to claim 2, characterized in that, The dispersive element is selected from one of the following: grating pairs, glass pillars, or optical fibers.

4. The framing imaging device according to claim 3, characterized in that, The amplitude-splitting element is configured as an aperture array.

5. The framing imaging device according to claim 3, characterized in that, The amplitude-dividing element is configured as a filter array.

6. The framing imaging device according to any one of claims 4 or 5, wherein the first Fourier lens and the second Fourier lens constitute a 4f system.

7. A framing imaging system, characterized in that, include: A light source structure, a framing imaging device and an imaging structure as described in any one of claims 1-6, wherein the framing imaging device forms an illumination area based on the light source emitted from the light source structure, and the imaging structure images an object located in the illumination area.

8. The framing imaging system according to claim 7, characterized in that, The light source structure includes a pulsed laser and a beam expander and collimator, wherein the pulsed laser is used to generate a laser light source, and the beam expander and collimator is used to collimate the laser light source into the incident light of the framing imaging device.

9. The framing imaging system according to claim 8, characterized in that, The imaging structure includes a detector and at least one lens, wherein the at least one lens is used to image the object onto the image plane of the detector, and the detector is used to acquire the image of the image plane and transmit it to an external electronic device.

Images