Monopulse three-dimensional coherent diffraction imaging device

Abstract

The utility model discloses a monopulse three-dimensional coherent diffraction imaging device, which comprises a light source for generating incident light, and an angle modulation module, a first focusing lens and a detection module which are sequentially arranged along a light path of the incident light, a plurality of light through holes are formed in the angle modulation module and are used for adjusting the incident light to form a plurality of diffracted light beams; the first focusing lens is used for modulating the diffracted beam into a parallel beam; an imaging interval is formed between the first focusing lens and the detection module and is used for placing a sample; and the detection module is used for collecting multi-angle diffraction images after the plurality of parallel light beams irradiate the sample. By modulating the exposure angle, the multi-angle diffraction image of the sample can be obtained only through single exposure, so that monopulse three-dimensional imaging can be realized, the imaging time is shortened, the coherence requirement of incident light is reduced, and the radiation damage of the sample is reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of microscopic imaging, in particular to a single-pulse three-dimensional coherent diffraction imaging device. Background Art

[0002] Coherent Diffractive Imaging (CDI) is a new lensless imaging method that uses highly coherent illumination light to perform high-resolution imaging of samples. In theory, it can achieve imaging resolution at the wavelength limit. It is an important development direction of microscopic imaging and has broad application prospects in the fields of biology, environment, medicine, chemistry and materials, especially for samples with high resolution requirements. With the development of the third and fourth generation synchrotron radiation sources, the flux and coherence of X-rays have been greatly improved. X-ray coherent diffraction imaging technology has become one of the essential technologies in the third and fourth generation synchrotron radiation sources and free electron lasers.

[0003] The commonly used three-dimensional coherent diffraction imaging technology mainly irradiates a beam of incident light with known information onto the sample, and uses a two-dimensional detector to measure the diffraction signal generated by the sample, reconstructs the sample information through a phase recovery algorithm, and obtains the amplitude and phase information of the sample at the same time; during the imaging process, the sample is rotated and scanned for multiple exposures to achieve multiple measurements of the sample, obtain sample diffraction signals at different rotation angles, and then integrate all information to obtain a three-dimensional image of the sample. The most important feature of CDI technology is that the imaging device does not need to use focusing elements, so the imaging resolution is not affected by the processing accuracy, and theoretically can achieve nanometer-level or even atomic-level imaging resolution.

[0004] However, the existing three-dimensional coherent diffraction imaging process requires multiple exposures of the sample, which is complex to operate and takes a long time to measure. In addition, the same incident light must be used for each exposure, which places high demands on the stability and coherence of the incident light.

[0005] Therefore, the existing technology still has the defects of low working efficiency and large detection error, and needs to be improved and developed. Utility Model Content

[0006] In view of the above-mentioned deficiencies in the prior art, the purpose of the present invention is to provide a single-pulse three-dimensional coherent diffraction imaging device, aiming to solve the problems of low imaging efficiency and inaccurate detection results in the existing three-dimensional coherent diffraction imaging process.

[0007] The technical solution of the utility model is as follows:

[0008] A single-pulse three-dimensional coherent diffraction imaging device, comprising a light source for generating incident light, and an angle modulation module, a first focusing lens and a detection module sequentially arranged along the optical path of the incident light; the angle modulation module is provided with a plurality of light holes for adjusting the incident light to form a plurality of diffracted light beams; the first focusing lens is used to modulate the diffracted light beams into parallel light beams; an imaging interval is formed between the first focusing lens and the detection module for placing a sample; the detection module is used to collect multi-angle diffraction images after the sample is irradiated by the plurality of parallel light beams.

[0009] The single-pulse three-dimensional coherent diffraction imaging device, wherein the angle modulation module includes a pinhole array plate, a plurality of light-through hole arrays are arranged on the pinhole array plate, and the plurality of light-through holes are all located in the area projected by the light outlet of the light source on the pinhole array plate.

[0010] The single-pulse three-dimensional coherent diffraction imaging device, wherein the coherence length of the incident light is 2-10 times the diameter of the light-through hole.

[0011] The single-pulse three-dimensional coherent diffraction imaging device, wherein the diameter of the light-through hole is R, satisfies the following relationship: ;in, is the wavelength of the incident light; is the focal length of the first focusing lens; is the length of the projection of the sample in the direction perpendicular to the light path.

[0012] The single-pulse three-dimensional coherent diffraction imaging device, wherein the detection module includes a second focusing lens and a detector arranged in sequence along the optical path of the incident light, and the second focusing lens is used to focus multiple beams of diffracted light after irradiating the sample onto the detector.

[0013] The single-pulse three-dimensional coherent diffraction imaging device, wherein the distance between the first focusing lens and the second focusing lens is m, satisfies the following relationship: ;in, is the focal length of the second focusing lens.

[0014] The single-pulse three-dimensional coherent diffraction imaging device, wherein the optical parameters of the second focusing lens are the same as those of the first focusing lens.

[0015] The single-pulse three-dimensional coherent diffraction imaging device, wherein the angle modulation module includes a grating or a spatial light modulator.

[0016] The single-pulse three-dimensional coherent diffraction imaging device, wherein the detection module is arranged in the Fraunhofer diffraction region.

[0017] The single-pulse three-dimensional coherent diffraction imaging device, wherein the light source includes a laser.

[0018] Compared with the prior art, the embodiment of the utility model has the following advantages:

[0019] The single-pulse three-dimensional coherent diffraction imaging device disclosed by the utility model sets an angle modulation module in front of the first focusing lens, adjusts the incident light into multiple diffraction beams, and emits them to the first focusing lens from different angles, thereby forming multiple intersecting parallel beams behind the first focusing lens, and performing multi-angle exposure on the sample in the imaging interval; the diffraction images of the sample at multiple angles can be collected by the detection module, so as to reconstruct the sample through the phase recovery algorithm. It can be seen that the diffraction signals of multiple angles on the sample are collected by a single exposure to achieve single-pulse three-dimensional imaging, which is simple and efficient to operate, is conducive to reducing costs, reducing errors caused by repeated detection, reducing the coherence requirements for the incident light, and improving the accuracy of the detection results. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0021] Figure 1 It is a schematic structural diagram of the single-pulse three-dimensional coherent diffraction imaging device in the utility model.

[0022] Among them, 10, angle modulation module; 11, light hole; 20, first focusing lens; 30, detection module; 31, second focusing lens; 32, detector; 40, imaging area; 50, sample. DETAILED DESCRIPTION

[0023] In order to enable those skilled in the art to better understand the solution of the utility model, the following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0024] Variations in the shapes shown in the drawings may occur due to manufacturing techniques and / or tolerances. Therefore, the examples described herein are not limited to the specific shapes shown in the drawings but include variations in shapes that occur during manufacturing.

[0025] Although terms such as "first," "second," and "third" may be used herein to describe various members, components, regions, layers, or portions, these members, components, regions, layers, or portions are not limited by these terms. Rather, these terms are only used to distinguish one member, component, region, layer, or portion from another member, component, region, layer, or portion. Therefore, without departing from the teachings of the examples described herein, the first member, component, region, layer, or portion referred to may also be referred to as the second member, component, region, layer, or portion.

[0026] For ease of description, spatial relational terms such as "above", "upper", "below", and "lower" may be used herein to describe the relationship of one element to another element as shown in the accompanying drawings. Such spatial relational terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the accompanying drawings. For example, if the device in the accompanying drawings is turned over, an element described as being "above" or "upper" relative to another element will subsequently be "below" or "lower" relative to the other element. Thus, the term "above" includes both "above" and "below" orientations depending on the spatial orientation of the device. The device may also be positioned in other ways, and the spatial relational terms used herein will be interpreted accordingly.

[0027] The terms used herein are only used to describe various examples and are not used to limit the present disclosure. Unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. The terms "include", "comprise" and "have" list the stated features, quantities, operations, components, elements and / or their combinations that exist, but do not exclude the existence or addition of one or more other features, quantities, operations, components, elements and / or their combinations.

[0028] See also Figure 1 In one embodiment of the utility model application, a single-pulse three-dimensional coherent diffraction imaging device is disclosed, which includes a light source for generating incident light, and an angle modulation module 10, a first focusing lens 20 and a detection module 30 arranged in sequence along the optical path of the incident light; the angle modulation module 10 is provided with a plurality of light holes 11 for adjusting the incident light to form a plurality of diffracted light beams; the first focusing lens 20 is used to modulate the diffracted light beams into parallel light beams; an imaging area 40 is formed between the first focusing lens 20 and the detection module 30 for placing a sample 50; the detection module 30 is used to collect multi-angle diffraction images after the sample 50 is irradiated by a plurality of parallel light beams.

[0029] The light source disclosed in this embodiment includes but is not limited to lasers, such as gas lasers, solid-state lasers, semiconductor lasers, etc., all of which can generate coherent light. The light beam emitted by the laser is the incident light, which is emitted to the angle modulation module 10 .

[0030] The single-pulse three-dimensional coherent diffraction imaging device disclosed in this embodiment is equipped with an angle modulation module 10 in front of the first focusing lens 20, which adjusts the incident light into multiple diffraction light beams, and emits them to the first focusing lens 20 from different angles, thereby forming multiple intersecting parallel light beams behind the first focusing lens 20, and performing multi-angle exposure on the sample 50 in the imaging area 40, so that multiple angles of the sample 50 can be detected at the same time, without rotating the sample 50 or performing detection in multiple times.

[0031] Specifically, the detection module 30 can collect diffraction images of the sample 50 at multiple angles, separate the diffraction images at multiple angles in the detection module 30, and then reconstruct the sample 50 through the phase recovery algorithm. It can be seen that by collecting diffraction signals at multiple angles on the sample 50 through a single exposure, a single-pulse three-dimensional imaging is achieved, and there is no need to scan the sample 50 or rotate the sample 50. The operation is simple and efficient, which is conducive to reducing costs, reducing errors caused by repeated detection, reducing the coherence requirements for the incident light, and improving the accuracy of the detection results.

[0032] Specifically, the width of the imaging interval 40 disclosed in this embodiment is greater than the focal length of the first focusing lens 20, and the sample 50 is placed at the focal position of the first focusing lens 20. Alternatively, when the sample 50 is large in size, in order to capture a complete image, the sample 50 can be placed behind the focus of the first focusing lens 20. However, it is still required that each parallel light beam can irradiate the sample 50 to avoid incomplete detection.

[0033] Specifically, after the detection module 30 disclosed in this embodiment collects the multi-angle diffraction image, the steps of reconstructing the three-dimensional image are as follows:

[0034] Step 1: Separate the diffraction images at various angles to obtain n diffraction signals exposed at different angles; wherein n is a positive integer greater than 1.

[0035] Step 2: construct an initial three-dimensional sample.

[0036] Step three, transform the initial three-dimensional sample into reciprocal space, and project the diffraction signals of the above multiple angles onto the spherical surface of the Ewald sphere at different angles as amplitude constraints of the reciprocal space, thereby generating a reconstructed three-dimensional sample.

[0037] In the field of solid state physics, reciprocal space is a space that describes the properties of objects, which corresponds to real space (positive space). In real space, the existence of an object can be described by particle coordinates, while in reciprocal space, the properties of an object can be described by coordinate points, but these properties appear as waves in real space. There is a Fourier transform relationship between reciprocal space and real space, which is equivalent to the transformation between coordinate space and wave vector space. Ewald's diffraction sphere is an important concept for determining the diffraction direction of a crystal in reciprocal space.

[0038] Step 4: transform the reconstructed three-dimensional sample into real space and use three-dimensional support constraints in the real space.

[0039] Step 5: Repeat steps 3 and 4 multiple times until the sample function converges to obtain a reconstructed three-dimensional image.

[0040] It can be seen that the single-pulse three-dimensional coherent diffraction imaging device disclosed in this embodiment mainly achieves the work completed by multiple exposures of traditional imaging devices through single exposure, thereby improving the collection efficiency of diffraction signals and facilitating the processing and calculation of diffraction signals.

[0041] Specifically, as another implementation of this embodiment, the angle modulation module 10 is disclosed to include a pinhole array plate, a plurality of light-through holes 11 are arrayed on the pinhole array plate, and the plurality of light-through holes 11 are located in the area projected by the light outlet of the light source on the pinhole array plate. In this embodiment, the pinhole array plate is an opaque flat plate, which is arranged directly opposite to the light source, and directly opposite to the light outlet of the light source. A plurality of light-through holes 11 are arranged on the pinhole array plate, so that part of the incident light can pass through the pinhole array plate to form multiple beams of diffracted light, thereby playing the role of irradiating the first focusing lens 20 from different positions, and achieving the purpose of irradiating multiple beams of light with only one beam of incident light.

[0042] Specifically, in the present embodiment, the number of light holes 11 can be 3, 5, 7, etc. A central light hole 11 is provided at the center position opposite to the light outlet of the light source, and the other light holes 11 are arranged in a radial or circular array around the central light hole 11. The light beam emitted from the central light hole 11 can eventually illuminate the front of the sample 50, and the light beams emitted from the other light holes 11 can illuminate the sample 50 from other angles, thereby finally constructing a multi-angle diffraction image of the sample 50.

[0043] Specifically, as another implementation of this embodiment, it is disclosed that the coherence length of the incident light is 2-10 times the diameter of the light-through hole 11. The incident light disclosed in this embodiment is coherent light, so in order to reduce the influence of the optical characteristics of the coherent light itself, the diameter of the light-through hole 11 is set to be much smaller than the coherence length of the incident light. When the coherence length of the incident light is 2 times or more than 2 times the diameter of the light-through hole 11, the transmittance of the incident light at the light-through hole 11 is good; of course, the ratio of the coherence length of the incident light to the diameter of the light-through hole 11 should be less than or equal to 10 times to avoid excessive manufacturing requirements, and if the light-through hole 11 is too small, it will affect the amount of light and cannot meet the imaging requirements of the device.

[0044] Specifically, as another implementation of this embodiment, it is disclosed that the diameter of the light-through hole is R, which satisfies the following relationship: ;in, is the wavelength of the incident light; is the focal length of the first focusing lens; is the length of the projection of the sample in the direction perpendicular to the light path.

[0045] Specifically, as another implementation of this embodiment, the distance between two adjacent light holes 11 is disclosed to be d, satisfying the following relationship: ;in, is the maximum diffraction angle of the sample. For metal samples, The value of is generally less than 0.2; for biological samples, The value of is generally less than 0.1; for visible light, The value of is generally less than 0.4; for hard X-rays, The value is generally less than 0.02.

[0046] The adjacent light holes 11 are placed as far apart as possible to separate the subsequent multiple beams of light to avoid overlapping and mutual interference.

[0047] For example Figure 1 As shown, as another implementation of this embodiment, the detection module 30 is disclosed to include a second focusing lens 31 and a detector 32 arranged in sequence along the optical path of the incident light, and the second focusing lens 31 is used to focus the multiple beams of diffracted light after irradiating the sample 50 to the detector 32.

[0048] In this embodiment, the sample 50 is arranged near the focus of the first focusing lens 20. The multiple beams of light irradiated onto the surface of the sample 50 form multiple diffused diffraction light beams after diffraction. The second focusing lens 31 is arranged to gather the multiple diffused diffraction light beams, thereby forming a converged or parallel multi-angle diffraction image behind the second focusing lens 31, which is convenient for the detector 32 to collect.

[0049] In this embodiment, the light source, the first focusing lens 20, the second focusing lens 31 and the detector 32 form a 4F imaging system, that is, a linear optical information processing system. The detector 32 disclosed in this embodiment includes but is not limited to a laser detector 32, and by collecting the light signal of the diffracted light beam with sample information, a diffraction image at multiple angles can be obtained.

[0050] Specifically, as another implementation of this embodiment, it is disclosed that the distance between the first focusing lens and the second focusing lens is m, satisfying the following relationship: ;in, is the focal length of the second focusing lens.

[0051] For example Figure 1 As shown, in this embodiment, an imaging interval 40 is provided between the first focusing lens 20 and the second focusing lens 31, and a width of the imaging interval 40 is set to be the sum of the focal length of the first focusing lens 20 and the focal length of the second focusing lens 31, so that the sample 50 can be placed at a common focal position of the first focusing lens 20 and the second focusing lens 31, and the sample 50 can be irradiated at a position where the light beam is concentrated, so as to collect a complete diffraction image of the sample 50.

[0052] Specifically, as another implementation of this embodiment, it is disclosed that the optical parameters of the second focusing lens 31 are the same as those of the first focusing lens 20. The first focusing lens 20 and the second focusing lens 31 disclosed in this embodiment are arranged along the optical path and can be arranged as two identical lenses, thereby reducing the types of optical devices, facilitating the construction of an imaging system, and reducing costs; and, by using the same lens, the focal lengths of the first focusing lens 20 and the second focusing lens 31 are the same, which facilitates the setting of the imaging interval 40, and also facilitates the accurate location of the sample 50, thereby reducing the difficulty of imaging and improving work efficiency.

[0053] Specifically, as another implementation of this embodiment, the angle modulation module 10 is disclosed to include a grating or a spatial light modulator. The angle modulation module 10 disclosed in this embodiment can be adaptively designed according to the size and volume of the sample 50 to be tested, and made into a plurality of pinhole array plates, and can also play a beam splitting role through a grating or a spatial light modulator.

[0054] An optical device composed of a large number of parallel slits of equal width and equal spacing is called a grating. A commonly used grating is made by engraving a large number of parallel grooves on a glass sheet. The grooves are opaque parts, and the smooth part between two grooves can transmit light, which is equivalent to a slit. A refined grating has thousands or even tens of thousands of grooves within a width of 1 cm. This grating that utilizes the diffraction of transmitted light is called a transmission grating. There is also a grating that utilizes the diffraction of reflected light between two grooves. For example, many parallel grooves are engraved on a surface coated with a metal layer, and the smooth metal surface between the two grooves can reflect light. This grating is called a reflection grating. In this embodiment, a transmission grating can be used, and multiple grooves of the grating can be used instead of the light-through hole 11 to achieve the effect of forming multiple diffracted light beams.

[0055] A spatial light modulator is a device that can modulate a parameter of a light field through liquid crystal molecules under active control, such as by modulating the amplitude of the light field, modulating the phase through the refractive index, modulating the polarization state through the rotation of the polarization plane, or realizing the conversion of incoherent light to coherent light, thereby writing certain information into the light wave to achieve the purpose of light wave modulation. A spatial light modulator can generally be divided into a reflective type and a transmissive type according to the different readout methods of the readout light. In this embodiment, a transmissive spatial light modulator can be used as the angle modulation module 10.

[0056] It should be noted that the types of angle modulation modules 10 are only exemplified in this embodiment, but are not exhaustive. The protection scope of the present invention is not limited to this. As long as other types of angle modulation modules 10 can achieve the technical effects disclosed in this application, they should also be within the scope of protection of this application as equivalent replacements for the concept of the present invention.

[0057] Specifically, as another implementation of this embodiment, it is disclosed that the detection module 30 is arranged in the Fraunhofer diffraction area. In optics, Fraunhofer diffraction is also called far-field diffraction. The fluctuation of the far field is closer to the properties of parallel light beams and plane waves. Therefore, the imaging of Fraunhofer diffraction only changes in size, but not in shape, and the jagged edges of the imaging are reduced. In this embodiment, the detection module 30 is arranged in the Fraunhofer diffraction area so that a complete diffraction signal with no distortion in shape can be collected, thereby increasing the effectiveness of the collected diffraction signal.

[0058] In summary, the present application discloses a single-pulse three-dimensional coherent diffraction imaging device, which includes a light source for generating incident light, and an angle modulation module 10, a first focusing lens 20 and a detection module 30 arranged in sequence along the optical path of the incident light; the angle modulation module 10 is provided with a plurality of light holes 11 for adjusting the incident light to form a plurality of diffracted light beams; the first focusing lens 20 is used to modulate the diffracted light beams into parallel light beams; an imaging area 40 is formed between the first focusing lens 20 and the detection module 30 for placing a sample 50; the detection module 30 is used to collect multi-angle diffraction images after the sample 50 is irradiated by a plurality of parallel light beams. This embodiment realizes single-pulse three-dimensional imaging by collecting diffraction signals at multiple angles on the sample 50 through a single exposure, which is simple and efficient to operate, is conducive to reducing costs, reducing errors caused by repeated detection, reducing the coherence requirements for the incident light, and improving the accuracy of the detection results.

[0059] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application may be combined with each other.

[0060] It should be noted that the utility model takes a single-pulse three-dimensional coherent diffraction imaging device as an example to introduce the specific structure and working principle of the utility model, but the application of the utility model is not limited to a single-pulse three-dimensional coherent diffraction imaging device, and can also be applied to the production and use of other similar workpieces.

[0061] It should be understood that the present invention is not limited to the precise structure described above and shown in the drawings, and various modifications and changes can be made without departing from the scope thereof. The scope of the present invention is limited only by the appended claims.

[0062] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A single pulse three-dimensional coherent diffraction imaging device, characterized in that: It comprises a light source for generating incident light, and an angle modulation module, a first focusing lens and a detection module which are sequentially arranged along the optical path of the incident light; the angle modulation module is provided with a plurality of light holes for adjusting the incident light to form a plurality of diffracted light beams; the first focusing lens is used to modulate the diffracted light beams into parallel light beams; an imaging area is formed between the first focusing lens and the detection module for placing a sample; the detection module is used to collect multi-angle diffraction images after the sample is irradiated by the plurality of parallel light beams.

2. The single pulse three-dimensional coherent diffraction imaging device according to claim 1, characterized in that: The angle modulation module comprises a pinhole array plate, a plurality of light-through hole arrays are arranged on the pinhole array plate, and the plurality of light-through holes are all located in the area projected by the light outlet of the light source on the pinhole array plate.

3. The single pulse three-dimensional coherent diffraction imaging device according to claim 2, characterized in that: The coherence length of the incident light is 2-10 times the diameter of the light-through hole.

4. The single pulse three-dimensional coherent diffraction imaging device according to claim 2, characterized in that: The diameter of the light-through hole is R, which satisfies the following relationship: in, is the wavelength of the incident light; is the focal length of the first focusing lens; is the length of the projection of the sample in the direction perpendicular to the light path.

5. The single pulse three-dimensional coherent diffraction imaging device according to claim 4, characterized in that: The detection module comprises a second focusing lens and a detector which are sequentially arranged along the optical path of the incident light, and the second focusing lens is used for focusing the multiple beams of diffracted light after irradiating the sample onto the detector.

6. The single pulse three-dimensional coherent diffraction imaging device according to claim 5, characterized in that: The distance between the first focusing lens and the second focusing lens is m, which satisfies the following relationship: in, is the focal length of the second focusing lens.

7. The single pulse three-dimensional coherent diffraction imaging device according to claim 6, characterized in that: The second focusing lens has the same optical parameters as the first focusing lens.

8. The single pulse three-dimensional coherent diffraction imaging device according to claim 1, characterized in that: The angle modulation module includes a grating or a spatial light modulator.

9. The single pulse three-dimensional coherent diffraction imaging device according to claim 1, characterized in that: The detection module is arranged in the Fraunhofer diffraction area.

10. The single pulse three-dimensional coherent diffraction imaging device according to claim 1, characterized in that: The light source includes a laser.

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