Target three-dimensional diffraction pattern regulation device and method based on binary optical component

Abstract

The application discloses a target three-dimensional diffraction pattern regulation and control device and method based on a binary optical component, an optimal binary hologram is calculated in a reverse design mode through an improved optimal accumulation algorithm, and a binary optical component is designed in combination with a digital microlens array device, and is used for regulating and controlling generation of an arbitrary target three-dimensional diffraction pattern in free space. The improved optimal accumulation algorithm can realize dynamic modulation of the target three-dimensional diffraction pattern through only one optimization process, and has real-time reconfigurability; the target three-dimensional diffraction pattern generated based on the digital microlens array device has unique polarization independence, and can work under any incident polarization state, thereby opening up a new way for holographic technology, information processing, microscopic imaging, optical communication, information encryption and data storage.

Description

Technical Field

[0001] This invention belongs to the field of light field manipulation technology, specifically a device and method for manipulating the three-dimensional diffraction pattern of a target based on binarized optical components. It is used to solve the inverse design problem of generating arbitrary target three-dimensional diffraction patterns using binarized amplitude-type holograms in three-dimensional free space. It can be used in fields such as holography, information processing, microscopic imaging, optical communication, information encryption, and data storage. Background Technology

[0002] In free space, when the incident beam is known, the diffraction pattern distribution on any plane of free space can be determined using the well-known Huygens-Fresnel principle. Conversely, solving the inverse design problem of generating diffraction patterns for arbitrary targets in three-dimensional free space is extremely important. The inverse Huygens-Fresnel principle can be widely applied to calculate the complex amplitude distribution of the incident beam to generate the diffraction pattern of the target. However, the inverse Huygens-Fresnel principle requires modulating the complex amplitude distribution of the incident beam, which necessitates complex optical component fabrication processes, and the modulation efficiency of the complex amplitude of the light field is typically low. Therefore, solving its inverse design problem remains challenging and urgent.

[0003] Recently, various algorithms and methods have been proposed, such as the Gerchberg-Saxton (GS) algorithm, genetic algorithms, ant colony optimization, particle swarm optimization, and simulated annealing. In particular, the GS algorithm has been widely used for inverse design of pure phase-type optical components to control target diffraction patterns. However, pure phase-type optical components do not respond to terahertz waves and X-rays, thus limiting their application in the broad spectrum. In fact, pure amplitude-type optical components can be widely used in areas where pure phase-type optical components are not feasible, such as wavelength multiplexers for functional waveguide design and the optimization of nanostructures. Especially, binarized amplitude-type optical components, due to their advantages of simple nanopore structure design, convenient fabrication, and high modulation efficiency, have made their design a long-sought-after problem for researchers.

[0004] Genetic algorithms are the most widely used method in the inverse design of binary amplitude-type optical components. Furthermore, a novel optimization algorithm has been proposed for designing an aperture to generate a two-dimensional diffraction pattern for a target. However, if such an aperture is required to achieve complex functions, the search space for its parameters becomes extremely large, thus placing high demands on computational resources and time. Compared to genetic algorithms, improved genetic algorithms search for optimal solutions by progressively changing the state of initially generated genome elements in a random sequence. The pure mutation evolution process of the improved genetic algorithm forces the genome to converge monotonically towards the target, significantly reducing computational costs. However, when the search space is very large, the convergence time of the improved genetic algorithm remains relatively long, and its convergence capability is limited.

[0005] Therefore, the aforementioned algorithms fall far short of satisfactory requirements in terms of search space and computational power. To address the complex inverse design problem with a large number of pixels, a piecewise hierarchical evolutionary algorithm has been proposed for designing binarized amplitude-type optical components. This method significantly improves its search space while achieving faster convergence, and experiments have verified the generation of broadband full-color high-fidelity images based on binarized amplitude-type optical components. However, to date, previously reported methods for designing binarized amplitude-type optical components are limited to modulating two-dimensional diffraction patterns of targets, require complex computational schemes, typically lack reconfigurability, and generally have limited achievable functionalities. Summary of the Invention

[0006] The present invention addresses the shortcomings of existing technologies and methods by proposing a target three-dimensional diffraction pattern control device and method based on binary optical components. This device aims to generate arbitrary target three-dimensional diffraction patterns in free space, and the generated patterns are polarization-independent, allowing operation under any incident polarization state. This opens up a new avenue for holographic technology, information processing, microscopic imaging, optical communication, information encryption, and data storage.

[0007] To achieve the above-mentioned objectives, the present invention adopts the following technical solution:

[0008] The present invention provides a target three-dimensional diffraction pattern control device based on binarized optical components, which includes: a laser source, a half-wave plate, a first lens, a second lens, a reflector, a digital microlens array, a third lens, a pinhole, a fourth lens, a camera, a one-dimensional displacement stage, and a computer.

[0009] The laser source is used to emit coherent laser light;

[0010] The half-wave plate is used to change the linear polarization direction of the coherent laser source, and by changing the principal axis direction of the half-wave plate, the coherent laser source becomes an X-ray polarized beam with arbitrary linear polarization direction after passing through the half-wave plate.

[0011] The collimation and beam expansion system, composed of the first lens and the second lens, is used to collimate and expand the X-ray polarized beam to obtain an expanded X-ray polarized collimated laser beam.

[0012] The reflector is used to change the transmission direction of the expanded X-ray polarized collimated laser beam, so that the reflected X-ray polarized collimated laser beam can irradiate the effective target surface of the digital microlens array at an incident angle of 24°.

[0013] The computer loads a binarized hologram onto the digital microlens array to form a binarized optical component. The 1 and 0 values ​​of the pixels in the binarized hologram represent the on and off states of each unit in the digital microlens array, respectively. The computer controls the on and off states of each unit in the digital microlens array according to the binarized hologram, so that the X-ray polarized collimated laser beam on the digital microlens array can pass through the open units and cannot pass through the closed units, thus obtaining an X-ray polarized light field.

[0014] The X-ray polarized light field passes through the third lens, the pinhole, and the fourth lens in sequence. The 0th order beam corresponds to the binarized amplitude distribution of the target-controlled X-ray polarized light field. The pinhole is used to filter the 0th order beam on the focal plane of the third lens to obtain the controlled X-ray polarized light field.

[0015] The modulated X-ray polarized light field continues to propagate in free space along the direction of light propagation according to the principle of Huygens-Fresnel diffraction, so as to form a three-dimensional spatial diffraction light field.

[0016] The computer loads a series of random binary holograms onto the digital microlens array and controls the digital microlens array to generate a series of random binary amplitude-type X-ray polarized light fields.

[0017] The camera is fixed on the one-dimensional displacement stage. By adjusting the front and rear positions of the one-dimensional displacement stage, the camera can collect the diffraction pattern distribution of the three-dimensional spatial diffraction light field on different planes and send it to the computer.

[0018] The computer calculates the optimal binarized hologram based on the set target three-dimensional diffraction pattern distribution, the diffraction pattern distribution of the three-dimensional spatial diffraction light field on different planes, and a series of random binarized holograms using an improved optimal accumulation algorithm. The optimal binarized hologram is then loaded onto the digital microlens array to achieve the generation of the target three-dimensional diffraction pattern.

[0019] The present invention provides a method for controlling a target three-dimensional diffraction pattern based on binarized optical components, characterized in that it is applied to the target three-dimensional diffraction pattern control device and is performed according to the following steps:

[0020] Step 1: Turn on the laser source to emit a coherent laser light source;

[0021] Step 2: By changing the principal axis direction of the half-wave plate, the coherent laser source becomes an X-ray polarized beam with arbitrary linear polarization direction after passing through the half-wave plate.

[0022] Step 3: Turn on the digital microlens array;

[0023] Step 4: Use the computer to randomly generate M×N binary holograms {A} with dimensions H×V. m,n |m∈[1,M],n∈[1,N]}, where A m,n Let m represent the nth binary hologram in the m-th binary hologram group; M represents the number of binary hologram groups, and N represents the number of binary holograms in each group; H and V represent the total number of horizontal and vertical patterns in each binary hologram, respectively; m∈[1,M], n∈[1,N];

[0024] Step 5: Using the computer, convert M×N binarized holograms {A} of dimension H×V into holograms. m,n |m∈[1,M],n∈[1,N]} is loaded onto the digital microlens array;

[0025] Step 6: Use the computer to control the digital microlens array to dynamically switch between M×N binarized holograms {A} m,n |m∈[1,M],n∈[1,N]}, thereby regulating and generating a series of random binary amplitude-type light fields. The random binary amplitude-type light fields continue to propagate forward in free space according to the principle of Huygens-Fresnel diffraction to form a three-dimensional spatial diffraction light field.

[0026] Step 7: By changing the front and rear positions of the one-dimensional displacement stage and controlling the camera to synchronously acquire speckle intensity information of the three-dimensional diffracted light field on different target planes, a speckle intensity information set is obtained. in, Represents the k-th plane z k The nth binary hologram A in the mth group of binary holograms above m,n The corresponding speckle intensity information, k∈[1,K], where K represents the total number of target planes; The total number of horizontal and vertical patterns are denoted as I and J, respectively;

[0027] Step 8: Convert the nth binarized hologram A from the mth binarized hologram group. m,n The generated three-dimensional diffraction patterns corresponding to the K planes are denoted as

[0028] Step 9: Define the target 3D diffraction patterns corresponding to K planes. in Represents the k-th plane z k The corresponding two-dimensional diffraction pattern of the target;

[0029] Step 10: Calculate the three-dimensional diffraction pattern using equation (1) With the target three-dimensional diffraction pattern T 3D The correlation coefficient CC(m,n) is used to obtain the M×N three-dimensional diffraction patterns and the target three-dimensional diffraction pattern T. 3D The correlation coefficient {CC(m,n)|m∈[1,M],n∈[1,N]}:

[0030]

[0031] In equation (1), express The average value, T represents 3D The average value; where i and j represent the average value of ; and T 3D The row and column indices of the elements, i∈[1,I], j∈[1,J];

[0032] Step 11: Find the maximum value B(m) in the m-th row of CC(m,n), thus obtaining the set of maximum values ​​for each row of CC(m,n) {B(m)|m∈[1,M]}; and record the column number C(m) corresponding to the maximum value B(m) in the m-th row of CC(m,n), thus obtaining the corresponding set of column numbers {C(m)|m∈[1,M]}, where B(m)∈[0,1], C(m)∈[1,N];

[0033] Step 12: Based on the upgraded optimal cumulative algorithm, construct the m-th first matrix E using equation (2). m :

[0034] E m =B(m)A m,C(m (2)

[0035] In equation (2), A m,C(m) Let C(m) be the C-th binary hologram in the m-th group of binary holograms, thus obtaining the set of M first matrices {E}. m |m∈[1,M]};

[0036] Step 13: Based on the upgraded optimal cumulative algorithm, construct the m-th second matrix F using equation (3). m :

[0037] F m =B(m)[1-A m,C(m) (3)

[0038] Based on equation (3), we obtain the set of M second matrices {F}. m |m∈[1,M]};

[0039] Step 14: Calculate the third matrix E using equation (4) total :

[0040]

[0041] Step 15: Calculate the fourth matrix F using equation (5) total :

[0042]

[0043] Step 16: Sequentially process the third matrix E total and the fourth matrix F total The corresponding element values ​​are compared to obtain the optimal binarized hologram P. best :

[0044] If the third matrix E total The value of the element in the h-th row and v-th column is compared with that of the fourth matrix F. total If the value of the element in the h-th row and v-th column is large, then the corresponding element in the h-th row and v-th column of the optimal binarized hologram has a value of 1, otherwise it has a value of 0; where h∈[1,H], v∈[1,V];

[0045] Step 17: The optimal binarized hologram P is processed by the computer. best Loaded onto the digital microlens array, the digital microlens array becomes a binary optical component, used to generate three-dimensional diffraction patterns in free space. in, Represents the k-th plane z k Two-dimensional diffraction patterns generated by up-regulation.

[0046] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0047] 1. Compared with traditional algorithms, the binarized amplitude hologram calculated by the upgraded optimal accumulation algorithm proposed in this invention can control the target three-dimensional diffraction pattern, which significantly improves the ability of the binarized amplitude hologram to control the multi-degree-of-freedom information of the diffraction pattern.

[0048] 2. The optimal accumulation algorithm proposed in this invention is extremely simple. It only requires simple addition and comparison operations to calculate the optimal binarized hologram, which greatly simplifies the optimization process and effectively shortens the optimization time.

[0049] 3. This invention only requires one optimization process and combines a digital microlens array with fast switching characteristics to achieve dynamic modulation of the three-dimensional diffraction pattern, ensuring the reconfigurability of the target three-dimensional diffraction pattern controlled by the method of this invention, thereby guaranteeing the arbitrariness of controlling the target three-dimensional diffraction pattern.

[0050] 4. Compared with traditional methods, the upgraded optimal accumulation algorithm used in this invention has a higher tolerance for environmental noise. Even in scattering environments, it can control the three-dimensional diffraction pattern of the target based on the optimal binarized hologram, which significantly improves the robustness of the method and optical system of this invention.

[0051] 5. The binary optical components designed based on digital microlens arrays in this invention have unique polarization-independent characteristics, can work under incident light with arbitrary polarization direction, ensure the generation of the same three-dimensional diffraction pattern, and have strong universality. Attached Figure Description

[0052] Figure 1 This is a schematic diagram of the device for controlling the three-dimensional diffraction pattern of a target using binary amplitude-type optical components according to the present invention.

[0053] Figure 2 This is a flowchart illustrating the use of binary amplitude-type optical components to control the three-dimensional diffraction pattern of a target in this invention.

[0054] Figure 3 A flowchart illustrating the reverse design of the optimal binarized hologram using the upgraded optimal accumulation algorithm employed in this invention;

[0055] The numbers in the diagram are: 1-Laser source, 2-Half-wave plate, 3-First lens, 4-Second lens, 5-Reflector, 6-Digital microlens array, 7-Third lens, 8-Pinhole, 9-Fourth lens, 10-Camera, 11-One-dimensional displacement stage, 12-Computer. Detailed Implementation

[0056] The present invention will now be described in detail with reference to the accompanying drawings and embodiments:

[0057] In this embodiment, a target three-dimensional diffraction pattern control device and method based on binarized optical components is proposed. An improved optimal accumulation algorithm is used to calculate the optimal binarized hologram through inverse design. Binarized optical components are designed using dynamically modulated binarized digital microlens array devices to generate arbitrary target three-dimensional diffraction patterns in free space. Compared to traditional algorithms, the method proposed in this invention only requires simple addition and comparison operations. Specifically, the improved optimal accumulation algorithm proposed in this invention can achieve dynamic modulation of the target three-dimensional diffraction pattern with only one optimization process and has real-time reconfigurability. Specifically, as... Figure 1 As shown, the target three-dimensional diffraction pattern control device based on binarized optical components includes: a laser source 1, a half-wave plate 2, a first lens 3, a second lens 4, a reflector 5, a digital microlens array 6, a third lens 7, a pinhole 8, a fourth lens 9, a camera 10, a one-dimensional displacement stage 11, and a computer 12.

[0058] Laser source 1 is a He-Ne laser, used to emit a coherent laser source with a wavelength of 633nm;

[0059] A coherent laser source with a wavelength of 633nm passes through a half-wave plate 2. By changing the principal axis direction of the half-wave plate 2, the coherent laser source with a wavelength of 633nm becomes an X-ray polarized beam with a wavelength of 633nm in an arbitrary linear polarization direction after passing through the half-wave plate 2.

[0060] The X-ray polarized beam passes sequentially through a collimation and beam expanding system consisting of a first lens 3 and a second lens 4 with focal lengths of 25.4 mm and 300 mm, respectively. The collimation and beam expanding system is used to collimate and expand the spot diameter of the X-ray polarized beam, making it into an X-ray polarized collimated laser beam with a spot diameter of 20 mm.

[0061] The expanded X-ray polarized collimated laser beam irradiates the reflector 5. The reflector 5 is used to change the transmission direction of the expanded X-ray polarized collimated laser beam, so that the reflected X-ray polarized collimated laser beam can irradiate the effective target surface of the digital microlens array 6 at an incident angle of 24°. The digital microlens array 6 is a binary optical component. A binary hologram is generated by random calculation using the computer 12. The computer 12 then loads the binary hologram onto the digital microlens array 6 and controls the digital microlens array 6 to modulate the incident X-ray polarized collimated laser beam according to the binary hologram. The digital microlens array has 1024×768 pixels, a pixel size of 5.86μm, and a beam area of ​​6.0mm×4.5mm reflected by the digital microlens array.

[0062] Computer 12 loads a binarized hologram onto digital microlens array 6 to form a binarized optical component. The 1 and 0 values ​​of the pixels in the binarized hologram represent the on and off states of each unit in digital microlens array 6, respectively. The computer controls the on and off states of each unit in digital microlens array 6 according to the binarized hologram, so that the X-ray polarized collimated laser beam on digital microlens array 6 can pass through the open units and cannot pass through the closed units, thereby obtaining an X-ray polarized light field with a binarized amplitude distribution.

[0063] The X-ray polarized collimated laser beam, after passing through the digital microlens array 6, sequentially passes through the third lens 7, the pinhole 8, and the fourth lens 9. The 0th order beam corresponds to the binarized amplitude distribution of the target-controlled X-ray polarized light field. Thus, the pinhole 8 filters the 0th order beam on the focal plane of the third lens 7 to obtain the controlled X-ray polarized light field. The focal lengths of the third lens 7 and the fourth lens 9 are 300mm and 60mm, respectively, which can further reduce the beam controlled by the digital microlens array 6. The area of ​​the controlled X-ray polarized light field after beam reduction is approximately 1.2mm × 0.9mm.

[0064] The modulated X-ray polarized light field continues to propagate in free space along the direction of light propagation according to the principle of Huygens-Fresnel diffraction, so as to form a three-dimensional spatial diffraction light field.

[0065] The computer 12 randomly generates 100,000 binary holograms and loads them onto the digital microlens array 6. The computer 12 then controls the digital microlens array 6 to generate a series of random binary amplitude-type X-ray polarized light fields.

[0066] The camera 10 is fixed on the one-dimensional displacement stage 11. By adjusting the front and rear positions of the one-dimensional displacement stage 11, the camera 10 can collect the diffraction patterns of the three-dimensional diffraction light field on different planes. The computer 12 triggers the camera 10 and the digital microlens array 6 to perform synchronous signal acquisition and send it to the computer 12.

[0067] Computer 12 calculates the optimal binarized hologram based on the set target three-dimensional diffraction pattern distribution, the diffraction pattern distribution of the three-dimensional spatial diffraction light field on different planes, and a series of random binarized holograms using an improved optimal accumulation algorithm. The optimal binarized hologram is then loaded onto the digital microlens array 6 to achieve the generation of the target three-dimensional diffraction pattern.

[0068] In this embodiment, although the digital microlens array 6 used consists of 1024×768 independent pixels, the number of effective incident modes used in this embodiment is 256×192, where each 4×4 pixels of the digital microlens array is considered as one effective input mode.

[0069] like Figure 2 As shown, a target three-dimensional diffraction pattern control method based on binarized optical components is applied to a target three-dimensional diffraction pattern control device based on binarized optical components, and is carried out according to the following steps:

[0070] Step 1: Turn on laser source 1 to emit a coherent laser source with a wavelength of 633nm;

[0071] Step 2: The coherent laser source passes through half-wave plate 2. By changing the principal axis direction of half-wave plate 2, the coherent laser source becomes an X-ray polarized beam with arbitrary linear polarization direction after passing through half-wave plate 2.

[0072] Step 3: The X-ray polarized beam passes sequentially through a collimation and beam expanding system consisting of a first lens 3 and a second lens 4 with focal lengths of 25.4 mm and 300 mm, respectively. The collimation and beam expanding system is used to collimate and expand the spot diameter of the X-ray polarized beam to obtain an expanded X-ray polarized collimated laser beam.

[0073] Step 4: Turn on the digital microlens array 6;

[0074] Step 5: Use a computer to randomly generate M×N binary holograms {A} with dimensions H×V. m,n |m∈[1,M],n∈[1,N]}, where A m,n Let m represent the nth binary hologram in the m-th binary hologram group; M represents the number of binary hologram groups, and N represents the number of binary holograms in each group; H and V represent the total number of horizontal and vertical patterns in each binary hologram, respectively; m∈[1,M], n∈[1,N]; in this embodiment, the values ​​of M and N are 10000 and 10, respectively, and the values ​​of H and V are 256 and 192, respectively.

[0075] Step 6: Use computer 12 to convert M×N binarized holograms {A} of dimension H×V into holograms. m,n |m∈[1,M],n∈[1,N]} are loaded onto the digital microlens array 8;

[0076] Step 7: Use computer 12 to control the digital microlens array 8 to dynamically switch between M×N binarized holograms {A} m,n|m∈[1,M],n∈[1,N]}, thereby regulating and generating a series of random binary amplitude-type light fields. According to the principle of Huygens-Fresnel diffraction, the series of random binary amplitude-type light fields continue to propagate forward in free space to form a three-dimensional diffraction light field.

[0077] Step 8: By changing the forward and backward positions of the one-dimensional displacement stage 11 and controlling the camera 12 to synchronously acquire speckle intensity information of the three-dimensional diffracted light field on different target planes, a speckle intensity information set is obtained. in, Represents the k-th plane z k The nth binary hologram A in the mth group of binary holograms above m,n The corresponding speckle intensity information, k∈[1,K], where K represents the total number of target planes; The total number of patterns in the horizontal and vertical directions are I and J, respectively.

[0078] Step 9: The process of reverse designing the optimal binarized hologram using the upgraded optimal accumulation algorithm is as follows: Figure 3 As shown:

[0079] Step 9.1: Convert the nth binarized hologram A from the mth binarized hologram group. m,n The generated three-dimensional diffraction patterns corresponding to the K planes are denoted as

[0080] Step 9.2: Define the target three-dimensional diffraction patterns corresponding to K planes. in Represents the k-th plane z k The corresponding two-dimensional diffraction pattern of the target;

[0081] Step 9.3: Calculate the three-dimensional diffraction pattern using equation (1) With the target three-dimensional diffraction pattern T 3D The correlation coefficient CC(m,n) is used to obtain the M×N three-dimensional diffraction patterns and the target three-dimensional diffraction pattern T. 3D The correlation coefficient {CC(m,n)|m∈[1,M],n∈[1,N]}:

[0082]

[0083] In equation (1), express The average value, T represents 3D The average value; where i and j represent the average value of ; and T 3D The i-th row and j-th column of the array, i∈[1,I], j∈[1,J].

[0084] Step 9.4: Find the maximum value B(m) in the m-th row of CC(m,n), thus obtaining the set of maximum values ​​for each row of CC(m,n) {B(m)|m∈[1,M]}; and record the column number C(m) corresponding to the maximum value B(m) in the m-th row of CC(m,n), thus obtaining the corresponding set of column numbers {C(m)|m∈[1,M]}, where B(m)∈[0,1], C(m)∈[1,N];

[0085] Step 9.5: Construct the m-th first matrix E using equation (2) m :

[0086] E m =B(m)A m,C(m) (2)

[0087] In equation (2), A m,C(m) Let C(m) be the C-th binary hologram in the m-th group of binary holograms, thus obtaining the set of M first matrices {E}. m |m∈[1,M]};

[0088] Step 9.6: Construct the m-th second matrix F using equation (3) m :

[0089] F m =B(m)[1-A m,C(m) (3)

[0090] Based on equation (3), we obtain the set of M second matrices {F}. m |m∈[1,M]};

[0091] Step 9.7: Calculate the third matrix E, which is the sum of the M first matrices, using equation (4). total :

[0092]

[0093] Step 9.8: Calculate the fourth matrix F, which is the sum of the M second matrices, using equation (5). total :

[0094]

[0095] Step 9.9: Sequentially process the third matrix E total and the fourth matrix F total The corresponding element values ​​are compared to obtain the optimal binarized hologram P. best :

[0096] If the third matrix E total The value of the element in the h-th row and v-th column is compared with that of the fourth matrix F. totalIf the value of the element in the h-th row and v-th column is large, then the corresponding element in the h-th row and v-th column of the optimal binarized hologram has a value of 1, otherwise it has a value of 0; where h∈[1,H], v∈[1,V];

[0097] Step 10: Use computer 12 to convert the above-mentioned optimal binarized hologram P best Loaded onto the digital microlens array 6, the digital microlens array 6 becomes a binary optical component, used to generate three-dimensional diffraction patterns in free space. in, Represents the k-th plane z k The two-dimensional diffraction pattern generated by the upper control;

[0098] Step 11: Use computer 12 to convert the above-mentioned optimal binarized hologram P best Loaded onto the digital microlens array 6, the digital microlens array 6 becomes a binary optical component, used to generate three-dimensional diffraction patterns in free space. in, Represents the k-th plane z k Two-dimensional diffraction patterns generated by up-regulation.

[0099] Step 12: Generate the three-dimensional diffraction pattern through experimental control. With the target three-dimensional diffraction pattern Intensity similarity measurements are performed, and the fidelity of the intensity is used to quantitatively characterize the accuracy of generating a target three-dimensional diffraction pattern in free space.

[0100] Step 13: By changing the target's three-dimensional diffraction pattern By repeating steps 9 and 10, dynamic modulation of the target three-dimensional diffraction pattern can be achieved, ensuring the reconfigurability of the target three-dimensional diffraction pattern controlled by the present invention, thereby guaranteeing the arbitrariness of controlling the target three-dimensional diffraction pattern.

Claims

1. A target three-dimensional diffraction pattern control device based on binarized optical components, characterized in that, include: Laser source (1), half-wave plate (2), first lens (3), second lens (4), mirror (5), digital microlens array (6), third lens (7), pinhole (8), fourth lens (9), camera (10), one-dimensional displacement stage (11), computer (12); The laser source (1) is used to emit coherent laser light; The half-wave plate (2) is used to change the linear polarization direction of the coherent laser source, and by changing the principal axis direction of the half-wave plate (2), the coherent laser source becomes an X-ray polarized beam with arbitrary linear polarization direction after passing through the half-wave plate (2). The collimation and beam expansion system composed of the first lens (3) and the second lens (4) is used to collimate and expand the X-ray polarized beam to obtain an expanded X-ray polarized collimated laser beam. The reflector (5) is used to change the transmission direction of the expanded X-ray polarized collimated laser beam so that the reflected X-ray polarized collimated laser beam can irradiate the effective target surface of the digital microlens array (6) at an incident angle of 24°. The computer (12) loads the binarized hologram onto the digital microlens array (6) to form a binarized optical component. The 1 and 0 values ​​of the pixels in the binarized hologram represent the opening and closing of each unit in the digital microlens array (6), respectively. The computer controls the opening and closing of each unit in the digital microlens array (6) according to the binarized hologram, so that the X-ray polarized collimated laser beam on the digital microlens array (6) can pass through the open unit and cannot pass through the closed unit, and obtains the X-ray polarized light field. After the X-ray polarized light field passes through the third lens (7), the small hole (8), and the fourth lens (9) in sequence, the 0th order beam corresponds to the binary amplitude distribution of the target-controlled X-ray polarized light field. Thus, the 0th order beam on the focal plane of the third lens (7) is filtered by the small hole (8) to obtain the controlled X-ray polarized light field. The modulated X-ray polarized light field continues to propagate in free space along the direction of light propagation according to the principle of Huygens-Fresnel diffraction, so as to form a three-dimensional spatial diffraction light field. The computer (12) loads a series of random binary holograms onto the digital microlens array (6) and controls the digital microlens array (6) to generate a series of random binary amplitude-type X-ray polarized light fields. The camera (10) is fixed on the one-dimensional displacement stage (11). By adjusting the front and rear positions of the one-dimensional displacement stage (11), the camera (10) can collect the diffraction pattern distribution of the three-dimensional spatial diffraction light field on different planes and send it to the computer (12). The computer (12) calculates the optimal binary hologram based on the set target three-dimensional diffraction pattern distribution, the diffraction pattern distribution of the three-dimensional spatial diffraction light field on different planes, and a series of random binary holograms using an improved optimal accumulation algorithm. The optimal binary hologram is then loaded onto the digital microlens array (6) to achieve the generation of the target three-dimensional diffraction pattern.

2. A method for controlling the three-dimensional diffraction pattern of a target based on binary optical components, characterized in that, It is applied in the target three-dimensional diffraction pattern control device according to claim 1, and is carried out according to the following steps: Step 1: Turn on the laser source (1) to emit a coherent laser source; Step 2: By changing the principal axis direction of the half-wave plate (2), the coherent laser source becomes an X-ray polarized beam with arbitrary linear polarization direction after passing through the half-wave plate (2); Step 3: Turn on the digital microlens array (6); Step 4: Use the computer (12) to randomly generate M×N binary holograms with dimensions H×V. ,in, This represents the nth binarized hologram in the m-th binarized hologram group; M represents the number of binarized hologram groups, N represents the number of binarized holograms in each group; H and V represent the total number of horizontal and vertical patterns in each binarized hologram, respectively. , ; Step 5: Use the computer (12) to convert M×N binarized holograms of dimension H×V. Loaded onto the digital microlens array (6); Step 6: Use the computer (12) to control the digital microlens array (6) to dynamically switch between M×N binarized holograms. This allows for the generation of a series of random, binary amplitude-type X-ray polarized light fields. These random, binary amplitude-type X-ray polarized light fields continue to propagate forward in free space according to the principle of Huygens-Fresnel diffraction, thereby forming a three-dimensional spatial diffraction field. Step 7: By changing the front and rear positions of the one-dimensional displacement stage (11) and controlling the camera (10) to synchronously acquire speckle intensity information of the three-dimensional spatial diffraction field on different target planes, a speckle intensity information set is obtained. ,in, Represents the k-th plane The nth binary hologram in the mth group of binary holograms above Corresponding speckle intensity information, K represents the total number of target planes; The total number of horizontal and vertical patterns are denoted as I and J, respectively; Step 8: Convert the nth binarized hologram from the mth binarized hologram group. The generated three-dimensional diffraction patterns corresponding to the K planes are denoted as ; Step 9: Define the target 3D diffraction patterns corresponding to K planes. ,in Represents the k-th plane The corresponding two-dimensional diffraction pattern of the target; Step 10: Calculate the three-dimensional diffraction pattern using equation (1) With the target three-dimensional diffraction pattern correlation coefficient Thus, M×N three-dimensional diffraction patterns and the target three-dimensional diffraction pattern are obtained. correlation coefficient : (1) In equation (1), express The average value, express The average value; where i and j represent the average value of ; and The row and column numbers of the elements. , ; Step 11: Search The maximum value in the m-th row Thus obtain The set of maximum values ​​in each row ; and write it down The maximum value in the m-th row Corresponding column number Thus, the corresponding set of columns is obtained. ,in, , ; Step 12: Based on the upgraded optimal cumulative algorithm, construct the m-th first matrix E using equation (2). m : (2) In equation (2), Represents the m-th binarized hologram. Zhang binarizes the hologram, thus obtaining a set of M first matrices. ; Step 13: Based on the upgraded optimal cumulative algorithm, construct the m-th second matrix F using equation (3). m : (3) Based on equation (3), a set of M second matrices is obtained. ; Step 14: Calculate the third matrix E using equation (4) total : (4) Step 15: Calculate the fourth matrix F using equation (5) total : (5) Step 16: Sequentially process the third matrix E total and the fourth matrix F total The corresponding element values ​​are compared to obtain the optimal binarized hologram. : If the third matrix E total The value of the element in the h-th row and v-th column is compared with that of the fourth matrix F. total If the value of the element in the h-th row and v-th column is large, then the corresponding element in the optimal binarized hologram has a value of 1 in the h-th row and v-th column; otherwise, it has a value of 0. , ; Step 17: The optimal binarized hologram is processed by the computer (12). Loaded onto the digital microlens array (6), the digital microlens array (6) becomes a binary optical element, used to generate a three-dimensional diffraction pattern in free space. ,in, Represents the k-th plane Two-dimensional diffraction patterns generated by up-regulation.

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