Preparation method and device of three-dimensional periodic structure

Abstract

The invention provides a preparation method and device of a three-dimensional periodic structure, and the method comprises the steps: obtaining a target three-dimensional multi-focus light spot array according to the size of a single periodic structure of the three-dimensional periodic structure, a preset focus light spot number and a preset focus light spot layer number; according to the target three-dimensional multi-focus light spot array, target three-dimensional multi-focus light spot light field distribution is obtained; obtaining a three-dimensional multi-focus light spot phase distribution diagram according to the target three-dimensional multi-focus light spot light field distribution; loading the three-dimensional multi-focus light spot phase distribution diagram to a spatial light modulator so as to modulate an incident light field formed by an initial pulse laser beam output by a laser into a three-dimensional multi-focus light spot light field; and according to the three-dimensional multi-focus light spot light field and a preset laser scanning path used for representing the shape of the single periodic structure of the three-dimensional periodic structure, processing the sample to prepare the three-dimensional periodic structure.

Description

Technical Field

[0001] At least one embodiment of the present disclosure relates to the field of micro-nano manufacturing technology, and more specifically to a method and device for preparing a three-dimensional periodic structure. Background Art

[0002] Femtosecond laser two-photon polymerization technology is a very promising micro-nano additive manufacturing method. It can construct arbitrary true three-dimensional structures with extremely high precision and resolution, and provide support for the preparation of functional devices in many cutting-edge micro-nano application fields. However, the traditional two-photon polymerization technology based on single-point direct writing has low efficiency, and its application in large-scale, large-scale practical production is hindered. Therefore, researchers have proposed a variety of processing strategies based on beam splitting and parallel scanning, which effectively improved the manufacturing efficiency of two-photon polymerization. However, the multi-focal points modulated by the current parallel processing strategy are limited to arrangement within a two-dimensional plane, which affects the flexibility of three-dimensional processing; the number of focal points and scanning speed are limited, and the processing efficiency is difficult to further improve.

[0003] If multiple foci arranged in three-dimensional space can be generated, multi-layer parallel processing can be performed, simplifying the workload of axial scanning and further improving efficiency. Although the relevant holographic modulation method can generate three-dimensional light fields or multiple foci, the quality and flexibility of its modulated light field are poor in processing applications, making it difficult to prepare high-resolution three-dimensional structures in polymer materials. Summary of the invention

[0004] In order to solve at least one of the above-mentioned and other technical problems in the prior art, the present disclosure provides a method and device for preparing a three-dimensional periodic structure, which can successfully prepare a three-dimensional periodic structure, improve the preparation efficiency of the three-dimensional periodic structure, and improve the resolution of the three-dimensional periodic structure.

[0005] According to one aspect of the present disclosure, there is provided a method for preparing a three-dimensional periodic structure, comprising:

[0006] According to the size of a single periodic structure of the three-dimensional periodic structure, the number of preset focal spots, and the number of preset focal spot layers, a target three-dimensional multi-focal spot array is obtained;

[0007] According to the above target three-dimensional multi-focal spot array, a target three-dimensional multi-focal spot light field distribution is obtained;

[0008] According to the above target three-dimensional multi-focal spot light field distribution, a three-dimensional multi-focal spot phase distribution diagram is obtained;

[0009] Loading the three-dimensional multi-focal spot phase distribution diagram into a spatial light modulator to modulate an incident light field formed by an initial pulse laser beam output by a laser into a three-dimensional multi-focal spot light field; and

[0010] According to the above three-dimensional multi-focus spot light field and the preset laser scanning path used to represent the single periodic structure shape of the above three-dimensional periodic structure, the sample is processed to prepare the above three-dimensional periodic structure.

[0011] According to an embodiment of the present disclosure, obtaining a three-dimensional multi-focal spot phase distribution diagram according to the target three-dimensional multi-focal spot light field distribution includes:

[0012] According to the amplitude distribution and initial random phase of the initial pulsed laser beam, an initial entrance pupil plane light field is obtained;

[0013] According to the initial entrance pupil plane light field, a first light field distribution of the initial entrance pupil plane light field in the k domain is obtained;

[0014] Performing a three-dimensional Fourier transform on the first light field distribution in the k-domain to obtain a first focused light field distribution;

[0015] Replacing the amplitude of the first focused light field distribution with the amplitude distribution in the target three-dimensional multi-focal spot light field distribution to obtain a second focused light field distribution;

[0016] Performing an inverse operation of three-dimensional Fourier transform on the second focused light field distribution to obtain a second light field distribution of the initial entrance pupil plane light field in the k domain;

[0017] According to the second light field distribution in the k-domain, a first entrance pupil plane light field is obtained;

[0018] The phase of the polarization component in the X direction of the first entrance pupil plane light field is retained, and the amplitude of the polarization component in the X direction is replaced by the amplitude distribution of the initial pulsed laser beam, and the polarization components in the Y direction and the Z direction are 0, so as to obtain a second entrance pupil plane light field;

[0019] Taking the second entrance pupil plane light field as the initial entrance pupil plane light field, iteratively performing an operation for obtaining light field distribution, a Fourier transform operation, an amplitude distribution replacement operation, and an inverse operation of Fourier transform to obtain a new entrance pupil plane light field until a preset iteration condition is satisfied;

[0020] The three-dimensional multi-focal spot phase distribution diagram is obtained according to the second entrance pupil plane light field obtained in the current iteration round when the preset iteration condition is met;

[0021] The preset iteration condition includes that the deviation of the amplitude of the first focused light field distribution obtained in the current iteration round and the target three-dimensional multi-focal spot light field distribution is within a target range.

[0022] According to an embodiment of the present disclosure, obtaining a first light field distribution of the initial entrance pupil plane light field in the k-domain according to the initial entrance pupil plane light field includes:

[0023] According to the initial entrance pupil plane light field, a first apodization plane light field distribution is obtained; and

[0024] The first apodization surface light field distribution is mapped onto the Ewald diffraction sphere to obtain the first light field distribution of the initial entrance pupil surface light field in the k domain.

[0025] According to an embodiment of the present disclosure, obtaining the first entrance pupil plane light field according to the second light field distribution in the k-domain includes:

[0026] Inverse mapping the portion of the second light field distribution in the k-domain located on the effective Ewald diffraction sphere to obtain a second apodization surface light field distribution; and

[0027] According to the second apodization surface light field distribution, the first entrance pupil surface light field is obtained.

[0028] According to an embodiment of the present disclosure, the light field distribution of the first apodization surface satisfies formula (1):

[0029] (1),

[0030] in, is the deflection matrix, is the above entrance pupil light field, for The spherical coordinates of the point.

[0031] According to an embodiment of the present disclosure, the geometric relationship between the first apodization surface light field distribution mapped to the first light field distribution in the k-domain satisfies formula (2):

[0032] (2),

[0033] Among them, the first light field distribution in the k domain is , , , Wave vector The projection components in three directions, for The spherical coordinates of the point.

[0034] According to an embodiment of the present disclosure, the amplitude of the first focused light field distribution is replaced by the amplitude distribution in the target three-dimensional multi-focal spot light field distribution to obtain the amplitude distribution in the second focused light field distribution. In the iterative operation The weight of each focus satisfies formula (3):

[0035] (3),

[0036] in is the reproduction intensity of the above focus, is the total number of the above foci, is the number of iterations, when When it is 0, it is the 0th iteration operation, that is, the weight value of the kth focus initially set. .

[0037] According to an embodiment of the present disclosure, the spacing between the plurality of focal points is the same as the size of a single periodic structure of the three-dimensional periodic structure.

[0038] According to another aspect of the present disclosure, a device for preparing a three-dimensional periodic structure is provided. The device for preparing a three-dimensional periodic structure adopts the method for preparing a three-dimensional periodic structure, and comprises:

[0039] A laser, adapted to provide an initial pulsed laser beam;

[0040] A computer, adapted to obtain a target three-dimensional multi-focal spot array according to the size of a single periodic structure of the three-dimensional periodic structure, the number of preset focal spots, and the number of preset focal spot layers; adapted to obtain a three-dimensional multi-focal spot phase distribution diagram according to the target three-dimensional multi-focal spot array;

[0041] A spatial light modulator, adapted to modulate an incident light field formed by an initial pulsed laser beam output by a laser into a three-dimensional multi-focal light spot light field based on the three-dimensional multi-focal light spot phase distribution diagram;

[0042] A microscope adapted to focus the three-dimensional multi-focal spot light field onto a sample surface; and

[0043] The piezoelectric displacement stage is suitable for supporting the sample and moving along the preset laser scanning path to prepare the three-dimensional periodic structure.

[0044] According to an embodiment of the present disclosure, the device for preparing the three-dimensional periodic structure further includes:

[0045] A spatial filtering component, adapted to perform spatial filtering on the above three-dimensional multi-focal spot light field; and

[0046] Sample monitoring kit, including:

[0047] A halogen lamp suitable for exciting the above sample to emit a fluorescent signal; and

[0048] A camera is adapted to receive the fluorescent signal and generate an image.

[0049] According to an embodiment of the present disclosure, a target three-dimensional multi-focal spot array is obtained according to the size of a single periodic structure of a three-dimensional periodic structure, a preset number of focal spots, and a preset number of focal spot layers; a target three-dimensional multi-focal spot light field distribution is obtained according to the target three-dimensional multi-focal spot array; a three-dimensional multi-focal spot phase distribution diagram is obtained according to the target three-dimensional multi-focal spot light field distribution; the three-dimensional multi-focal spot phase distribution diagram is loaded into a spatial light modulator to modulate an incident light field formed by an initial pulsed laser beam output by a laser into a three-dimensional multi-focal spot light field; and a sample is processed to prepare a three-dimensional periodic structure according to the three-dimensional multi-focal spot light field and a preset laser scanning path for representing the shape of a single periodic structure of a three-dimensional periodic structure. The preparation method of a three-dimensional periodic structure disclosed in the present disclosure improves the preparation efficiency of a three-dimensional periodic structure based on a three-dimensional multi-focal spot array, and improves the resolution of a three-dimensional periodic structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] The above contents and other purposes, features and advantages of the present disclosure will become more apparent through the following description of the embodiments of the present disclosure with reference to the accompanying drawings, in which:

[0051] Figure 1 A flow chart schematically shows a method for preparing a three-dimensional periodic structure according to an embodiment of the present disclosure;

[0052] Figure 2 The working principle diagram of the preparation device of the three-dimensional periodic structure according to the embodiment of the present disclosure is schematically shown;

[0053] Figure 3 A schematic diagram of a target three-dimensional multi-focus spot array in a method for preparing a three-dimensional periodic structure according to an embodiment of the present disclosure is schematically shown;

[0054] Figure 4 A flowchart of obtaining a three-dimensional multi-focal light spot phase distribution diagram according to a target three-dimensional multi-focal light spot light field distribution in a method for preparing a three-dimensional periodic structure according to an embodiment of the present disclosure is schematically shown;

[0055] Figure 5 The schematic diagram shows a process of obtaining a three-dimensional multi-focal spot phase distribution diagram according to a target three-dimensional multi-focal spot array in a method for preparing a three-dimensional periodic structure according to an embodiment of the present disclosure;

[0056] Figure 6 A three-dimensional multi-focus spot phase distribution diagram in a method for preparing a three-dimensional periodic structure according to an embodiment of the present disclosure is schematically shown; and

[0057] Figure 7A stereogram schematically shows a preset scanning trajectory of a single periodic structure shape in a three-dimensional square support structure in a method for preparing a three-dimensional periodic structure according to an embodiment of the present disclosure;

[0058] Figure 8 The SEM image of the three-dimensional square bracket structure prepared according to the method for preparing the three-dimensional periodic structure according to the embodiment of the present disclosure is schematically shown;

[0059] Fig. 9 The SEM image of the octahedral lattice structure prepared according to the method for preparing a three-dimensional periodic structure according to an embodiment of the present disclosure is schematically shown;

[0060] Fig.10 Schematically showing a ring SEM image prepared according to the method for preparing a three-dimensional periodic structure according to an embodiment of the present disclosure; and

[0061] Fig.11 The SEM image of the micro-helical structure prepared according to the method for preparing a three-dimensional periodic structure according to an embodiment of the present disclosure is schematically shown.

[0062] In the above drawings, the meanings of the reference numerals are as follows:

[0063] 1-Laser;

[0064] 2-half wave plate;

[0065] 3-Polarization beam splitter prism;

[0066] 4- beam expander assembly;

[0067] 41- first lens;

[0068] 42- second lens;

[0069] 5- Optical shutter;

[0070] 6- reflector;

[0071] 7-Spatial light modulator;

[0072] 8-spatial filtering component;

[0073] 81- third lens;

[0074] 82- aperture;

[0075] 83- fourth lens;

[0076] 9- Sample monitoring component;

[0077] 91- Camera;

[0078] 92- fifth lens;

[0079] 93-microscope;

[0080] 94-sample;

[0081] 95-Piezoelectric displacement stage;

[0082] 96-Halogen lamp. DETAILED DESCRIPTION

[0083] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. However, it should be understood that these descriptions are exemplary only and are not intended to limit the scope of the present disclosure. In the following detailed description, for ease of explanation, many specific details are set forth to provide a comprehensive understanding of the embodiments of the present disclosure. However, it is apparent that one or more embodiments may also be implemented without these specific details. In addition, in the following description, descriptions of known structures and technologies are omitted to avoid unnecessary confusion of the concepts of the present disclosure.

[0084] The terms used herein are only for describing specific embodiments and are not intended to limit the present disclosure. The terms "comprise", "include", etc. used herein indicate the existence of the features, steps, operations and / or components, but do not exclude the existence or addition of one or more other features, steps, operations or components.

[0085] All terms (including technical and scientific terms) used herein have the meanings commonly understood by those skilled in the art unless otherwise defined. It should be noted that the terms used herein should be interpreted as having a meaning consistent with the context of this specification and should not be interpreted in an idealized or overly rigid manner.

[0086] When using expressions such as "at least one of A, B, and C, etc.", they should generally be interpreted according to the meaning of the expression commonly understood by those skilled in the art (for example, "a system having at least one of A, B, and C" should include but is not limited to a system having A alone, B alone, C alone, A and B, A and C, B and C, and / or A, B, C, etc.).

[0087] The single-point direct writing processing efficiency of the related two-photon polymerization technology is low. The use of parallel processing strategies can improve manufacturing efficiency, but the multi-foci generated by the parallel processing strategy are mostly limited to arrangement within a two-dimensional plane, which limits the flexibility of three-dimensional processing. In addition, due to the limitations of the number of focal points and scanning speed in the current parallel processing strategy, as well as the technical bottlenecks of three-dimensional holographic light fields in processing applications, the processing efficiency of two-photon polymerization is low.

[0088] In view of this, the present disclosure provides a method for preparing a three-dimensional periodic structure, by obtaining a target three-dimensional multi-focal spot array according to the size of a single periodic structure of the three-dimensional periodic structure, a preset number of focal spots and a preset number of focal spot layers; obtaining a target three-dimensional multi-focal spot light field distribution according to the target three-dimensional multi-focal spot array; obtaining a three-dimensional multi-focal spot phase distribution diagram according to the target three-dimensional multi-focal spot light field distribution; loading the three-dimensional multi-focal spot phase distribution diagram into a spatial light modulator to modulate an incident light field formed by an initial pulsed laser beam output by a laser into a three-dimensional multi-focal spot light field; and processing a sample to prepare a three-dimensional periodic structure according to the three-dimensional multi-focal spot light field and a preset laser scanning path for representing the shape of a single periodic structure of the three-dimensional periodic structure. The method for preparing a three-dimensional periodic structure disclosed in the present disclosure improves the preparation efficiency of the three-dimensional periodic structure based on the three-dimensional multi-focal spot array, and improves the resolution of the three-dimensional periodic structure.

[0089] Figure 1 The flowchart of the method for preparing a three-dimensional periodic structure according to an embodiment of the present disclosure is schematically shown.

[0090] According to some embodiments of the present disclosure, Figure 1 As shown, the method for preparing the three-dimensional periodic structure includes operations S101 to S105.

[0091] In operation S101, a target three-dimensional multi-focal spot array is obtained according to the size of a single periodic structure of the three-dimensional periodic structure, the number of preset focal spots, and the number of preset focal spot layers.

[0092] In operation S102, a target three-dimensional multi-focal light spot light field distribution is obtained according to the target three-dimensional multi-focal light spot array.

[0093] In operation S103, a three-dimensional multi-focal light spot phase distribution diagram is obtained according to the target three-dimensional multi-focal light spot light field distribution.

[0094] In operation S104, the three-dimensional multi-focus spot phase distribution map is loaded into the spatial light modulator to modulate the incident light field formed by the initial pulse laser beam output by the laser into a three-dimensional multi-focus spot light field.

[0095] In operation S105, the sample is processed to prepare a three-dimensional periodic structure according to the three-dimensional multi-focus spot light field and a preset laser scanning path for representing a single periodic structure shape of the three-dimensional periodic structure.

[0096] According to some embodiments of the present disclosure, a target three-dimensional multi-focal spot array is obtained according to the size of a single periodic structure of a three-dimensional periodic structure, the number of preset focal spots, and the number of preset focal spot layers; a target three-dimensional multi-focal spot light field distribution is obtained according to the target three-dimensional multi-focal spot array; a three-dimensional multi-focal spot phase distribution diagram is obtained according to the target three-dimensional multi-focal spot light field distribution; the three-dimensional multi-focal spot phase distribution diagram is loaded into a spatial light modulator to modulate the incident light field formed by the initial pulse laser beam output by the laser into a three-dimensional multi-focal spot light field; and a sample is processed to prepare a three-dimensional periodic structure according to the three-dimensional multi-focal spot light field and a preset laser scanning path for representing the shape of a single periodic structure of a three-dimensional periodic structure. The preparation method of the three-dimensional periodic structure disclosed in the present disclosure improves the preparation efficiency of the three-dimensional periodic structure based on the three-dimensional multi-focal spot array, and improves the resolution of the three-dimensional periodic structure. The preparation method of the three-dimensional periodic structure disclosed in the present disclosure has the technical effects of low inter-surface crosstalk and high uniformity by flexibly adjusting the number of preset focal spots, the number of preset focal spots, and the spacing between the multi-focals in the target three-dimensional multi-focal spot array.

[0097] According to some embodiments of the present disclosure, the number of preset multi-focal light spots in the target three-dimensional multi-focal light spot array is restricted by the energy of the initial pulsed laser beam, because the energy of the initial pulsed laser beam will be evenly distributed to each focus in the target three-dimensional multi-focal light spot array under ideal conditions, and the energy of each focus cannot be less than the processing threshold to ensure the minimum processing capability, that is, the maximum number of preset multi-focal light spots depends on the initial pulsed laser energy. The array specifications of the preset multi-focal light spots can be reasonably configured according to the scale of the processed three-dimensional periodic structure.

[0098] According to some embodiments of the present disclosure, inter-surface crosstalk refers to the mutual influence of the focal points of different layers. This influence is caused, on the one hand, by the shape of the focus being an ellipsoid that is elongated in the propagation direction, and on the other hand, by the local peak noise of the light field intensity that occurs when the effect of modulating the focus generation is not ideal. The smaller the inter-layer spacing between the focal points, the greater the inter-surface crosstalk.

[0099] Figure 2 The working principle diagram of the preparation device of the three-dimensional periodic structure according to the embodiment of the present disclosure is schematically shown.

[0100] Another aspect of the present disclosure provides a three-dimensional periodic structure preparation device, using the above three-dimensional periodic structure preparation method, such as Figure 2As shown, the preparation device of the three-dimensional periodic structure includes a laser 1, a computer (not shown in the figure), a spatial light modulator 7, a microscope 93 and a piezoelectric displacement stage 95. The laser 1 is suitable for providing an initial pulse laser beam; the computer is suitable for obtaining a target three-dimensional multi-focal spot array according to the size of a single periodic structure of the three-dimensional periodic structure, the preset number of focal spots used to represent the number of periods of the three-dimensional periodic structure, and the preset number of focal spots used to represent the number of periodic layers of the three-dimensional periodic structure; and is suitable for obtaining a three-dimensional multi-focal spot phase distribution diagram according to the target three-dimensional multi-focal spot array. The spatial light modulator 8 is suitable for modulating the incident light field formed by the initial pulse laser beam output by the laser into a three-dimensional multi-focal spot light field based on the three-dimensional multi-focal spot phase distribution diagram; the microscope 93 is suitable for focusing the three-dimensional multi-focal spot light field onto the surface of the sample 94; and the piezoelectric displacement stage 95 is suitable for supporting the sample 94 and moving along the preset laser scanning path to prepare a three-dimensional periodic structure.

[0101] According to some embodiments of the present disclosure, a laser 1 is set to provide an initial pulse laser beam; a target three-dimensional multi-focal spot array is obtained by using a computer according to the size of a single periodic structure of the three-dimensional periodic structure, the preset number of focal spots used to represent the number of periods of the three-dimensional periodic structure, and the preset number of focal spots used to represent the number of periodic layers of the three-dimensional periodic structure; a three-dimensional multi-focal spot phase distribution diagram is obtained by using a computer according to the target three-dimensional multi-focal spot array; a spatial light modulator 7 is used to modulate the incident light field formed by the initial pulse laser beam output by the laser into a three-dimensional multi-focal spot light field based on the three-dimensional multi-focal spot phase distribution diagram; a microscope 93 is used to focus the three-dimensional multi-focal spot light field onto the surface of a sample 94; and a piezoelectric displacement stage 95 is used to support the sample 94 and move it along a preset laser scanning path to prepare a three-dimensional periodic structure, thereby improving the preparation efficiency of the three-dimensional periodic structure and improving the resolution of the three-dimensional periodic structure. According to some embodiments of the present disclosure, the above-mentioned three-dimensional periodic structure preparation device also includes a spatial filtering component 8 and a sample monitoring component 9. The spatial filtering component 8 is suitable for performing spatial filtering on the three-dimensional multi-focal spot light field; the sample monitoring component 9 includes a halogen lamp 96 and a camera 91, the halogen lamp 96 is suitable for exciting the sample to emit a fluorescent signal; the camera 91 is suitable for receiving the fluorescent signal and generating an image.

[0102] According to some embodiments of the present disclosure, a microscope 93 focuses a three-dimensional multi-focal spot light field onto the surface of a sample 94 to process the sample 94. When the processing of the sample 94 is completed, a halogen lamp 96 under the sample 94 is turned on to cause the sample 94 to emit fluorescence, which is then received by a camera (CCD) 91 and imaged. The image of the processed sample 94 is observed in real time on a computer, and the processing status of the sample 94 is monitored in real time based on the image, thereby enabling monitoring of the entire processing process of the sample 94.

[0103] According to some embodiments of the present disclosure, the preparation device of the three-dimensional periodic structure further includes a half-wave plate 2, a polarization beam splitter prism 3, a beam expander assembly 4, a light gate 5 and a reflector 6. The initial pulsed laser beam emitted by the laser 1 is adjusted to a suitable intensity by the half-wave plate 2 and the polarization beam splitter prism 3, and then expanded by the beam expander assembly 4 to match the spatial light modulator 7. The light gate 5 can control the on and off and exposure time of the initial pulsed laser beam after expansion. The initial pulsed laser beam after expansion is irradiated onto the spatial light modulator 7 through the reflector 6. The spatial light modulator 7 modulates the initial pulsed laser beam after intensity adjustment and expansion based on the three-dimensional multi-focal spot phase distribution diagram, that is, the initial pulsed laser beam after intensity adjustment and expansion is phase-modulated according to the phase information in the three-dimensional multi-focal spot phase distribution diagram, thereby forming a three-dimensional multi-focal spot light field.

[0104] According to some alternative embodiments of the present disclosure, the beam expander assembly 4 includes a first lens 41 and a second lens 42 .

[0105] According to some embodiments of the present disclosure, the spatial filter assembly 8 includes a third lens 81, an aperture 82, and a fourth lens 83. The third lens 81 and the fourth lens 83 are a 4F lens group, and the spatial filter assembly 8 is a 4F filter system. According to some replaceable embodiments of the present disclosure, the laser 1 is a femtosecond laser, the reflector 6 and the fifth lens 92 are high reflectivity lenses, the microscope 93 is a 60x microscope, and the sample 94 is a photoresist sample.

[0106] Figure 3 A schematic diagram of a target three-dimensional multi-focus spot array in a method for preparing a three-dimensional periodic structure according to an embodiment of the present disclosure is schematically shown.

[0107] According to some embodiments of the present disclosure, Figure 3 As shown, the target three-dimensional multi-focus spot array is a 3×3×3 dot matrix. The 3×3×3 dot matrix is ​​arranged in a certain pattern in three-dimensional space. The spacing between multiple focuses is the same as the size of a single periodic structure of the three-dimensional periodic structure.

[0108] According to some alternative embodiments of the present disclosure, the overall size of the prepared three-dimensional periodic structure is 5.9 μm×5.9 μm×7.8 μm, so the lateral spacing between the focuses in the target three-dimensional multi-focus spot array is set to 5.9 μm and the axial spacing between the focuses is set to 7.8 μm.

[0109] Figure 4 The flowchart of obtaining a three-dimensional multi-focal spot phase distribution diagram according to a target three-dimensional multi-focal spot light field distribution in a method for preparing a three-dimensional periodic structure according to an embodiment of the present disclosure is schematically shown.

[0110] According to some embodiments of the present disclosure, Figure 4 As shown, obtaining a three-dimensional multi-focal spot phase distribution diagram according to the target three-dimensional multi-focal spot light field distribution includes operations S201 to S209.

[0111] In operation S201 , an initial entrance pupil plane light field is obtained according to an amplitude distribution and an initial random phase of an initial pulsed laser beam.

[0112] In operation S202, a first light field distribution of the initial entrance pupil plane light field in k-domain is obtained according to the initial entrance pupil plane light field.

[0113] In operation S203, a three-dimensional Fourier transform is performed on the first light field distribution in the k-domain to obtain a first focused light field distribution.

[0114] In operation S204, the amplitude of the first focused light field distribution is replaced by the amplitude distribution in the target three-dimensional multi-focal spot light field distribution to obtain a second focused light field distribution.

[0115] In operation S205, an inverse operation of three-dimensional Fourier transform is performed on the second focused light field distribution to obtain a second light field distribution of the initial entrance pupil plane light field in the k-domain.

[0116] In operation S206, a first entrance pupil plane light field is obtained according to the second light field distribution in the k-domain.

[0117] In operation S207, the phase of the polarization component in the X direction in the first entrance pupil plane light field is retained, and the amplitude of the polarization component in the X direction is replaced by the amplitude distribution of the initial pulsed laser beam. , the polarization components in the Y and Z directions are 0, and the second entrance pupil light field is obtained.

[0118] In operation S208, the second entrance pupil plane light field is used as the initial entrance pupil plane light field, and the operation for obtaining the light field distribution, the Fourier transform operation, the amplitude distribution replacement operation, and the inverse operation of the Fourier transform are iteratively performed to obtain a new entrance pupil plane light field until the preset iteration condition is met.

[0119] In operation S209, a three-dimensional multi-focal spot phase distribution diagram is obtained according to the second entrance pupil plane light field obtained in the current iteration round when the preset iteration condition is met.

[0120] According to some embodiments of the present disclosure, the preset iteration condition includes that the deviation of the amplitude of the first focused light field distribution obtained in the current iteration round and the target three-dimensional multi-focal spot light field distribution is within a target range.

[0121] According to some embodiments of the present disclosure, the target range is that the uniformity of the multi-focal light spots in the first focused light field distribution is above 90%.

[0122] According to some embodiments of the present disclosure, the light amplitude distribution and the initial random phase Determine that the initial entrance pupil light field satisfies:

[0123] .

[0124] According to some embodiments of the present disclosure, obtaining a first light field distribution of the initial entrance pupil plane light field in the k-domain according to the initial entrance pupil plane light field includes obtaining a first apodization plane light field distribution according to the initial entrance pupil plane light field; and mapping the first apodization plane light field distribution onto an Ewald diffraction sphere to obtain a first light field distribution of the initial entrance pupil plane light field in the k-domain.

[0125] According to some embodiments of the present disclosure, obtaining the first entrance pupil plane light field according to the second light field distribution in the k-domain includes inverse mapping a portion of the second light field distribution in the k-domain located on the effective Ewald diffraction sphere to obtain a second apodization plane light field distribution; and obtaining the first entrance pupil plane light field according to the second apodization plane light field distribution.

[0126] According to some embodiments of the present disclosure, the distribution of the light field on the entrance pupil plane in the k-domain (i.e., the frequency domain or the spatial frequency domain) is the representation of the light field in the spatial frequency domain. The projections of the wave vector in the X, Y, and Z directions are , , , mapped to the k-domain as coordinates In the k-domain, the phase distribution reflects the phase variation of the light field at the spatial frequency; the complete representation of the light field in the k-domain contains the amplitude and phase information of the light wave at different spatial frequencies.

[0127] According to some embodiments of the present disclosure, the first entrance pupil plane light field is , that is, the complex amplitude distribution of the light field at the first entrance pupil plane is .

[0128] According to some embodiments of the present disclosure, the second entrance pupil plane light field satisfies:

[0129] .

[0130] According to some embodiments of the present disclosure, the light field distribution of the first apodization surface satisfies formula (1):

[0131] (1),

[0132] in, is the deflection matrix, is the entrance pupil light field, for The spherical coordinates of the point.

[0133] According to some embodiments of the present disclosure, the initial entrance pupil plane light field undergoes amplitude and deflection changes to obtain a first apodization plane light field distribution, where the apodization plane is the exit pupil plane.

[0134] According to some embodiments of the present disclosure, the geometric relationship of mapping the first apodization surface light field distribution to the first light field distribution in the k-domain satisfies formula (2):

[0135] (2),

[0136] Among them, the first light field distribution in k domain is , , , Wave vector The projection components in three directions, for The spherical coordinates of the point.

[0137] According to some embodiments of the present disclosure, middle satisfy , satisfy ,in, is the focal length of the lens.

[0138] According to some embodiments of the present disclosure, the first light field distribution in the k-domain is Perform three-dimensional Fourier transform to obtain the first focused light field distribution, which satisfies ,in, is the wavelength, is the refractive index of the medium, Represents the three-dimensional Fourier transform.

[0139] According to some embodiments of the present disclosure, the amplitude of the first focused light field distribution is replaced by the amplitude distribution in the target three-dimensional multi-focal spot light field distribution to obtain the amplitude distribution in the second focused light field distribution. In the iterative operation The weight of each focus satisfies formula (3):

[0140] (3),

[0141] in is the focal reproduction intensity, is the total number of foci. is the number of iterations, when When it is 0, it is the 0th round of replacement, that is, the weight value of the kth focus initially set. .

[0142] According to some embodiments of the present disclosure, in the holographic processing process, due to the existence of system errors, it is often necessary to locally adjust the energy in the focal array. In order to locally adjust the energy in the focal array, it is no longer necessary to make the overall energy tend to be uniform, but it is hoped that the energy of each focus can be independently regulated. Therefore, the weight of the above formula is modified to ,in is the target amplitude of the kth focus. The weights set in this way make the focus close to its designed amplitude in each iteration instead of tending to the overall mean. The weight of each focus can improve the intensity distribution uniformity of the three-dimensional multi-focus spot light field used for processing.

[0143] According to some embodiments of the present disclosure, the amplitude of the first focused light field distribution is replaced by the amplitude distribution in the target three-dimensional multi-focal spot light field distribution to obtain a second focused light field distribution. Satisfies formula (4):

[0144] (4),

[0145] in, It represents the amplitude distribution in the target three-dimensional multi-focal spot light field distribution, that is, the intensity distribution of the multi-focal points in the target three-dimensional multi-focal array. is the intensity distribution of the first focused light field, the intensity distribution of the first focused light field is the sum of the intensities of each polarization component ; To modify the weight distribution of the replacement amplitude, is a weight index between 0 and 1, Represents the phase angle.

[0146] According to some embodiments of the present disclosure, according to the formula , in the known Under the condition of inverse operation, the second light field distribution in k domain is obtained .

[0147] Figure 5 The flowchart of obtaining a three-dimensional multi-focal spot phase distribution diagram according to a target three-dimensional multi-focal spot array in a method for preparing a three-dimensional periodic structure according to an embodiment of the present disclosure is schematically shown.

[0148] According to some embodiments of the present disclosure, Figure 5As shown, a schematic diagram of a process for obtaining a three-dimensional multi-focal spot phase distribution diagram according to a target three-dimensional multi-focal spot array includes: obtaining a target three-dimensional multi-focal spot light field distribution according to the target three-dimensional multi-focal spot array; obtaining an initial entrance pupil plane light field according to the amplitude distribution and the initial random phase of the initial pulsed laser beam; obtaining a first light field distribution of the initial entrance pupil plane light field in the k-domain according to the initial entrance pupil plane light field; performing a three-dimensional Fourier transform on the first light field distribution in the k-domain to obtain a first focused light field distribution; replacing the amplitude of the first focused light field distribution with the amplitude distribution in the target three-dimensional multi-focal spot light field distribution to obtain a second focused light field distribution; performing an inverse operation of the three-dimensional Fourier transform on the second focused light field distribution to obtain an initial The second light field distribution of the entrance pupil plane light field in the k domain; according to the second light field distribution in the k domain, the first entrance pupil plane light field is obtained; the phase of the polarization component in the X direction in the first entrance pupil plane light field is retained, and the amplitude of the polarization component in the X direction is replaced by the amplitude distribution of the initial pulsed laser beam, and the polarization components in the Y direction and Z direction are 0, so as to obtain the second entrance pupil plane light field; the second entrance pupil plane light field is used as the initial entrance pupil plane light field, and the operation for obtaining the light field distribution, the Fourier transform operation, the amplitude distribution replacement operation, and the inverse operation of the Fourier transform are iteratively performed to obtain a new entrance pupil plane light field until the preset iteration condition is met; according to the second entrance pupil plane light field obtained in the current iteration round when the preset iteration condition is met, a three-dimensional multi-focal spot phase distribution diagram is obtained. Wherein, the preset iteration condition includes that the deviation of the amplitude of the first focused light field distribution obtained in the current iteration round and the target three-dimensional multi-focal spot light field distribution is within the target range.

[0149] Figure 6 The diagram schematically shows a three-dimensional multi-focus spot phase distribution diagram in the method for preparing a three-dimensional periodic structure according to an embodiment of the present disclosure.

[0150] According to some embodiments of the present disclosure, Figure 6 The three-dimensional multi-focal spot phase distribution diagram is loaded onto the spatial light modulator 7 to modulate the incident light field formed by the initial pulse laser beam output by the laser 1 into a three-dimensional multi-focal spot light field.

[0151] According to some embodiments of the present disclosure, a laser 1 emits an initial pulse laser beam, which is adjusted to a suitable laser intensity by a half-wave plate 2 and a polarization beam splitter prism 3, and then expanded by a beam expander assembly 4 to match a spatial light modulator 8. An optical shutter 5 can control the on / off and exposure time of the laser beam. The expanded laser beam is irradiated onto a spatial light modulator 7 by a reflector 6, and the spatial light modulator 7 is loaded with a laser beam as shown in FIG. Figure 6The three-dimensional multi-focal spot phase distribution diagram shown in the figure is obtained, and the light beam is phase modulated according to the phase information in the three-dimensional multi-focal spot phase distribution diagram to generate a three-dimensional multi-focal spot light field. The modulated light beam passes through the 4F filtering system composed of the 4F lens group 81, 83 and the aperture 82, so that only the +1 order light of the three-dimensional multi-focal spot light field enters the microscope 93, and the other order lights are shielded, and the laser beam that has been spatially filtered is expanded again to match the entrance pupil plane entering the microscope 93. The +1 order light is reflected by the fifth lens 92 and enters the microscope 93 to process the sample 94 placed on the piezoelectric displacement stage 95. The halogen lamp 96 under the sample 94 is turned on to make the sample 94 emit fluorescence. After being received by the camera (charge coupled device CCD) 91, the processing progress of the three-dimensional periodic structure can be observed in real time on the computer, so as to realize the monitoring of the processing process of the entire three-dimensional periodic structure.

[0152] According to some embodiments of the present disclosure, the overall calculation of the three-dimensional multi-focal spot light field and the simultaneous calculation of the three polarization components in the three-dimensional multi-focal spot light field both require a relatively high computer storage space. Considering that the 4F lens pair in the processing light path projects the holographic surface of the spatial light modulator onto the entrance pupil surface of the microscope 93 at a 1:1 ratio, the phase distribution of the entrance pupil surface is the part of the phase loaded by the spatial light modulator 7 within the entrance pupil aperture of the microscope 93.

[0153] According to some embodiments of the present disclosure, the entrance pupil diameter of the microscope 93 is 8.1 mm, corresponding to a circular area with a central diameter of 648 pixels of the spatial light modulator 7. Therefore, a method is adopted in which only the circular area is used to calculate the phase, and all hologram pixels outside the area are set to 0, such as Figure 6 As shown, this method saves storage space and computing time for algorithm operation.

[0154] Figure 7 A stereoscopic diagram schematically shows a preset scanning trajectory of a single periodic structure shape in a three-dimensional square support structure in a method for preparing a three-dimensional periodic structure according to an embodiment of the present disclosure.

[0155] According to some embodiments of the present disclosure, when the target three-dimensional periodic structure is a three-dimensional square bracket structure, the preset scanning trajectory is as follows: Figure 7 The method for preparing the three-dimensional periodic structure disclosed in the present invention needs to be Figure 7 The target three-dimensional periodic structure can be obtained by scanning the trajectory shown once; if a 3×3 planar dot matrix is ​​used to process the same target three-dimensional periodic structure, the preset scanning trajectory needs to be repeated three times; if a single-focus direct writing is used to obtain the target three-dimensional periodic structure, the preset scanning trajectory needs to be repeated 27 times. Therefore, the preparation method of the three-dimensional periodic structure disclosed in the present invention can prepare the target three-dimensional periodic structure by multi-layer parallel processing, reducing the time spent in preparing the target three-dimensional periodic structure.

[0156] Figure 8 The SEM image of the three-dimensional square scaffold structure prepared according to the method for preparing a three-dimensional periodic structure according to an embodiment of the present disclosure is schematically shown. Figure 8 SEM images of the three-dimensional square scaffold structure at two different observation angles are shown.

[0157] Fig. 9 The SEM image of the octahedral lattice structure prepared according to the method for preparing a three-dimensional periodic structure according to an embodiment of the present disclosure is schematically shown; Fig.10 Schematically showing a ring SEM image prepared according to the method for preparing a three-dimensional periodic structure according to an embodiment of the present disclosure; and Fig.11 The SEM image of the micro-helical structure prepared according to the method for preparing a three-dimensional periodic structure according to an embodiment of the present disclosure is schematically shown.

[0158] It will be appreciated by those skilled in the art that the features described in the various embodiments and / or claims of the present disclosure may be combined and / or combined in a variety of ways, even if such combinations and / or combinations are not explicitly described in the present disclosure. In particular, the features described in the various embodiments and / or claims of the present disclosure may be combined and / or combined in a variety of ways without departing from the spirit and teachings of the present disclosure. All of these combinations and / or combinations fall within the scope of the present disclosure.

[0159] The embodiments of the present disclosure are described above. However, these embodiments are only for illustrative purposes and are not intended to limit the scope of the present disclosure. Although the embodiments are described above separately, this does not mean that the measures in the various embodiments cannot be used in combination to advantage. The scope of the present disclosure is defined by the attached claims and their equivalents. Without departing from the scope of the present disclosure, those skilled in the art may make a variety of substitutions and modifications, which should all fall within the scope of the present disclosure.

Claims

1. A method for preparing a three-dimensional periodic structure, comprising: According to the size of a single periodic structure of the three-dimensional periodic structure, the number of preset focal light spots, and the number of preset focal light spot layers, a target three-dimensional multi-focal light spot array is obtained; According to the target three-dimensional multi-focal spot array, a target three-dimensional multi-focal spot light field distribution is obtained; According to the target three-dimensional multi-focal spot light field distribution, a three-dimensional multi-focal spot phase distribution diagram is obtained; Loading the three-dimensional multi-focal spot phase distribution diagram into a spatial light modulator to modulate an incident light field formed by an initial pulse laser beam output by a laser into a three-dimensional multi-focal spot light field; and According to the three-dimensional multi-focus spot light field and a preset laser scanning path for representing a single periodic structure shape of the three-dimensional periodic structure, a sample is processed to prepare the three-dimensional periodic structure.

2. The method for preparing a three-dimensional periodic structure according to claim 1, wherein: The step of obtaining a three-dimensional multi-focal light spot phase distribution diagram according to the target three-dimensional multi-focal light spot light field distribution comprises: Obtaining an initial entrance pupil plane light field according to the amplitude distribution and initial random phase of the initial pulsed laser beam; According to the initial entrance pupil plane light field, obtaining a first light field distribution of the initial entrance pupil plane light field in k-domain; Performing a three-dimensional Fourier transform on the first light field distribution in the k-domain to obtain a first focused light field distribution; Replacing the amplitude of the first focused light field distribution with the amplitude distribution in the target three-dimensional multi-focal spot light field distribution to obtain a second focused light field distribution; Performing an inverse operation of a three-dimensional Fourier transform on the second focused light field distribution to obtain a second light field distribution of the initial entrance pupil plane light field in the k domain; Obtaining a first entrance pupil plane light field according to the second light field distribution in the k-domain; The phase of the polarization component in the X direction of the first entrance pupil plane light field is retained, and the amplitude of the polarization component in the X direction is replaced by the amplitude distribution of the initial pulsed laser beam, and the polarization components in the Y direction and the Z direction are 0, so as to obtain a second entrance pupil plane light field; Taking the second entrance pupil plane light field as the initial entrance pupil plane light field, iteratively performing an operation for obtaining light field distribution, a Fourier transform operation, an amplitude distribution replacement operation, and an inverse operation of Fourier transform to obtain a new entrance pupil plane light field until a preset iteration condition is satisfied; Obtaining the three-dimensional multi-focal spot phase distribution diagram according to the second entrance pupil plane light field obtained in the current iteration round when the preset iteration condition is met; The preset iteration condition includes that the deviation of the amplitude of the first focused light field distribution obtained in the current iteration round and the target three-dimensional multi-focal spot light field distribution is within a target range.

3. The method for preparing a three-dimensional periodic structure according to claim 2, wherein: The step of obtaining a first light field distribution of the initial entrance pupil plane light field in the k-domain according to the initial entrance pupil plane light field comprises: Obtaining a first apodization surface light field distribution according to the initial entrance pupil surface light field; and The first apodization surface light field distribution is mapped onto the Ewald diffraction sphere to obtain a first light field distribution of the initial entrance pupil surface light field in the k-domain.

4. The method for preparing a three-dimensional periodic structure according to claim 2, wherein: The obtaining of the first entrance pupil plane light field according to the second light field distribution in the k-domain comprises: Inverse mapping a portion of the second light field distribution in the k-domain located on the effective Ewald diffraction sphere to obtain a second apodization surface light field distribution; The first entrance pupil plane light field is obtained according to the second apodization plane light field distribution.

5. The method for preparing a three-dimensional periodic structure according to claim 3, wherein: The light field distribution of the first apodization surface satisfies formula (1): （1）， in, is the deflection matrix, is the entrance pupil light field, for The spherical coordinates of the point.

6. The method for preparing a three-dimensional periodic structure according to claim 3, wherein: The geometric relationship between the first apodization surface light field distribution mapped to the first light field distribution in the k-domain satisfies formula (2): （2）， Among them, the first light field distribution in the k domain is , , , Wave vector The projection components in three directions, for The spherical coordinates of the point.

7. The method for preparing a three-dimensional periodic structure according to claim 2, wherein: The amplitude of the first focused light field distribution is replaced by the amplitude distribution in the target three-dimensional multi-focal spot light field distribution to obtain the amplitude distribution in the second focused light field distribution. In the iterative operation The weight of each focus satisfies formula (3): （3）， in is the reproduction intensity of the focus, is the total number of foci, is the number of iterations, when When it is 0, it is the 0th iteration operation, that is, the weight value of the kth focus set initially. .

8. The method for preparing a three-dimensional periodic structure according to claim 7, wherein: The intervals between the plurality of focal points are the same as the size of a single periodic structure of the three-dimensional periodic structure.

9. A device for preparing a three-dimensional periodic structure, using the method for preparing a three-dimensional periodic structure according to any one of claims 1 to 8, the device for preparing a three-dimensional periodic structure comprising: A laser, adapted to provide an initial pulsed laser beam; A computer, adapted to obtain a target three-dimensional multi-focal spot array according to the size of a single periodic structure of the three-dimensional periodic structure, the number of preset focal spots, and the number of preset focal spot layers; Suitable for obtaining a three-dimensional multi-focal spot phase distribution diagram according to the target three-dimensional multi-focal spot array; A spatial light modulator, adapted to modulate an incident light field formed by an initial pulsed laser beam output by a laser into a three-dimensional multi-focal light spot light field based on the three-dimensional multi-focal light spot phase distribution diagram; A microscope, adapted to focus the three-dimensional multi-focal spot light field onto a sample surface; as well as The piezoelectric displacement stage is suitable for supporting the sample and moving along the preset laser scanning path to prepare the three-dimensional periodic structure.

10. The device for preparing a three-dimensional periodic structure according to claim 9, wherein: Also includes: A spatial filtering component, adapted to perform spatial filtering on the three-dimensional multi-focal spot light field; as well as Sample monitoring kit, including: a halogen lamp, adapted to excite the sample to emit a fluorescent signal; as well as A camera is adapted to receive the fluorescent signal and generate an image.

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