Dynamic metasurface light field modulation element and method

Abstract

The application provides a dynamic metasurface light field modulation element, comprising: a metasurface structure layer, the metasurface structure layer has a plurality of nano modulation structures arranged in an array, the metasurface structure layer is divided into two or more modulation regions, each of the modulation regions has a plurality of nano modulation structures, each of the modulation regions corresponds to a target image, and the nano modulation structures in each of the modulation regions are phase-encoded according to the corresponding target image; and an electrically controlled switch layer, the electrically controlled switch layer has a plurality of electrically controlled switches arranged in an array, the electrically controlled switch layer is divided into two or more switch regions, each of the switch regions has a plurality of electrically controlled switches, and the plurality of switch regions correspond to the plurality of modulation regions one by one. The application can realize an electrically controllable, low-cost and easily integrated dynamic modulation mechanism under the premise of taking into account high resolution and high information capacity.

Description

Technical Field

[0001] This invention relates to the field of light field manipulation technology, and in particular to a dynamic metasurface light field manipulation element and method. Background Technology

[0002] In existing technologies, there are two main light field modulation techniques. One is dynamic light field modulation, which typically relies on spatial light modulators. Spatial light modulators can change the emitted light field by loading and calculating a phase map, thereby achieving a certain degree of dynamic holographic display. However, existing spatial light modulators are limited by factors such as large pixel size, limited modulation bandwidth, complex diffraction orders, and large system size. They often suffer from problems such as small field of view, insufficient spatial bandwidth product, limited display resolution, and low system integration, making it difficult to meet the application requirements of high-quality, miniaturized, and wide-field-of-view dynamic holographic displays. The other is static light field modulation, which mainly uses metasurface modulation devices, that is, the phase pattern is fixed after micro-nano fabrication. Although this modulation method has high display quality and spatial resolution, it cannot quickly switch the display content according to actual needs, and it is also difficult to achieve real-time dynamic display.

[0003] The two existing light field modulation methods cannot simultaneously achieve the advantages of high spatial resolution and high information capacity, as well as a dynamic modulation mechanism that is electrically controllable, low-cost, and easy to integrate. Summary of the Invention

[0004] The dynamic metasurface optical field modulation element and method provided by this invention can achieve an electrically controllable, low-cost, and easily integrated dynamic modulation mechanism while taking into account both high resolution and high information capacity.

[0005] In a first aspect, the present invention provides a dynamic metasurface optical field modulation element, comprising:

[0006] A metasurface structure layer having multiple nanoscale control structures arranged in an array, the metasurface structure layer being divided into two or more control regions, each control region having multiple nanoscale control structures, each control region corresponding to a target image, and the nanoscale control structures within each control region performing phase encoding based on the corresponding target image; The electronically controlled switch layer has multiple electronically controlled switches arranged in an array. The electronically controlled switch layer is divided into two or more switch regions, and each switch region has multiple electronically controlled switches. The multiple switch regions correspond one-to-one with multiple control regions.

[0007] Optionally, each of the control regions includes multiple control sub-regions, each control sub-region includes one or more rows / columns of the nano-control structure, and the control sub-regions of two or more control regions are arranged alternately.

[0008] Optionally, each of the control regions includes multiple control sub-regions, and each control sub-region includes N. M nanostructures, wherein the sub-regions of two or more control regions are arranged alternately in both row and column directions, wherein N and M are both not less than 1.

[0009] Optionally, each control region includes N M of the nanostructures, wherein both N and M are not less than 1.

[0010] Optionally, each of the control regions includes multiple nanostructures, and the nanostructures in two or more control regions are randomly and sparsely distributed.

[0011] Optionally, two or more control regions correspond to the target image at two or more scales, wherein the nanoscale control structures of the two or more control regions are distributed in a multi-scale nested manner.

[0012] Optionally, the electronically controlled switch layer includes an array of polymer-dispersed liquid crystals, which are fixed by prepolymer polymerization.

[0013] Optionally, the electronically controlled switch layer further includes a driving electrode. The driving electrode adopts a matrix addressing structure and has two or more driving regions. The two or more driving regions correspond one-to-one with two or more switching regions, so as to drive the polymer-dispersed liquid crystal in the corresponding switching region to undergo a state change through the voltage change of the driving region.

[0014] Optionally, it also includes: A control module is electrically connected to the electronically controlled switch layer. The control module controls two or more switch areas according to a preset timing sequence, so that the two or more switch areas are opened and closed according to the preset timing sequence.

[0015] Secondly, the present invention also provides a method for controlling the optical field of a dynamic metasurface, which is achieved by controlling any of the aforementioned dynamic metasurface optical field control elements, the method comprising: According to a preset timing sequence, two or more switching areas in the electronically controlled switch layer are controlled to open according to the preset timing sequence. When the light source passes through the corresponding switching area and the corresponding control area, it is controlled by the control area to form a target image, thus forming a dynamic display of multiple target images by multiple control areas.

[0016] The technical solution provided by this invention addresses the problems of existing metasurface control devices, such as difficulty in achieving dynamic control, fixed display content, and unadjustable response speed. It combines the high-density optical field control capabilities of the electrically controlled switch layer and the metasurface structure layer, transforming the static, fixed control method of the metasurface structure into a dynamically controllable, switchable, and tunable display. Compared to the control method of traditional spatial light modulators, the technical solution provided by this invention utilizes the advantages of small size, high spatial resolution, and large information capacity of metasurface microstructure units, improving the integration of optical field control and the capacity of optical information channels, and avoiding the problems of large pixel size, limited field of view, and multi-level diffraction in traditional spatial light modulators. Compared to traditional static metasurface optical field control methods, the technical solution provided by this invention introduces an electrically controlled switch layer above the metasurface to realize the opening and closing of different control areas, thereby achieving dynamic holographic display. It does not require changing the micro / nano structure of the metasurface structure layer itself during use; instead, the electrically controlled switch layer adjusts whether light enters or passes through the corresponding control area, thus simplifying the control method and making the structure implementation more direct. Furthermore, this invention does not simply superimpose an electrically controlled switch layer onto a metasurface structure layer. Instead, it achieves dynamic display through the combined use of three working principles: holographic phase encoding, spatial region multiplexing, and electrically controlled optical path gating. Specifically, the nanoscale control structure in the metasurface structure layer is used to solidify the phase distribution corresponding to the target image into a subwavelength micro / nano structure, thereby providing high spatial resolution wavefront modulation capability. Two or more control regions are used to store the holographic information of two or more target images in the same metasurface structure layer, thereby increasing the optical information capacity. The electrically controlled switch layer is used to open or close the incident optical path of different control regions without changing the geometry of the nanoscale control structure and the phase encoding result, thereby realizing the temporal switching of the target image. Through the above combination, this invention can combine the high resolution and high information capacity advantages of static metasurfaces with the region selection capability of the electrically controlled switch layer, avoiding the complex driving and processing problems caused by directly electrically tuning each nanoscale control structure. It also avoids the problems of large pixel size, large system volume, and low integration of traditional spatial light modulators. Therefore, this invention can achieve multi-image dynamic holographic display with a relatively simple device structure and control method. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of a dynamic metasurface optical field modulation element according to an embodiment of the present invention; Figure 2 This is a schematic diagram illustrating the display principle of a dynamic metasurface optical field modulation element in another embodiment of the present invention when the modulation sub-regions of two or more modulation regions are arranged alternately. Figure 3 In another embodiment of the present invention, the dynamic metasurface optical field modulation element includes N in each modulation region. Schematic diagram of the display principle when there are M nanoscale control structures. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] This invention provides a dynamic metasurface optical field modulation element, such as... Figure 1 As shown, it includes: A metasurface structure layer 100 has multiple nano-control structures arranged in an array. The metasurface structure layer 100 is divided into two or more control regions. Each control region has multiple nano-control structures. Each control region corresponds to a target image. The nano-control structures in each control region are phase-encoded according to the corresponding target image. In some embodiments, a metasurface structure layer 100 capable of reconstructing the target image is pre-designed using computational holography and metasurface coding methods. For the k-th target image, the intensity distribution of the target image can be used as a basis for initial design. Calculate the phase distribution required for the corresponding control region Where (x, y) represents the coordinates on the plane containing the metasurface structure layer 100, and (X, Y) represents the coordinates on the target image reconstruction plane. The manipulation of incident light by the metasurface structure layer 100 can be expressed as:

[0020] in, This represents the complex amplitude modulation function corresponding to the k-th modulation region. Indicates the amplitude modulation term. This represents the phase modulation term. When a phase-type metasurface is used... A constant or approximate constant can be used to make the target image primarily phase-encoded through phase distribution.

[0021] When the target image reconstruction distance is z, the reconstructed light field can be expressed as:

[0022] in, {·} represents the optical propagation operator that propagates from the metasurface plane to the plane containing the target image. This propagation operator can employ a Fourier propagation model, a Fresnel propagation model, or an angular spectrum propagation model. The corresponding reconstruction intensity is:

[0023] In the specific design process, the reconfiguration strength can be... With target image intensity The error between them meets preset conditions, such as the following optimization objective:

[0024] In some embodiments, the phase distribution It can be obtained through an iterative phase retrieval algorithm. For example, a Gerchberg-Saxton type algorithm can be used for calculation: first, an initial phase code is set in the k-th control region of the metasurface plane. Then, forward propagation is performed to obtain the light field of the plane containing the target image:

[0025] in, The light field of the plane containing the target image obtained in the nth iteration. This is the phase encoding used by the kth control region of the metasurface during the nth iteration; Preserving the phase of the light field obtained from the forward propagation on the plane containing the target image, and replacing the amplitude of the light field on the plane containing the target image with the target amplitude, we obtain:

[0026] in, For the light field after amplitude replacement, Let i be the target amplitude, and i be the imaginary number. Then, backpropagation is performed, and the phase of the metasurface plane is updated:

[0027] When the number of iterations reaches the preset number, or after obtaining the light field of the plane where the target image is located in each iteration, the reconstruction intensity of the image on the light field of the plane where the target image is located is reconstructed. Target image intensity of the target image The error between them is calculated when When the value is below a preset threshold, the phase distribution corresponding to the k-th target image is obtained. = Specifically, the reconstruction strength can be calculated using the following formula. Calculation:

[0028] Subsequently, the geometric parameters or rotation angles of each nanostructure within the corresponding control region are determined based on the phase distribution, thereby completing the phase encoding of the corresponding target image.

[0029] The nanoscale control structure in the metasurface structure layer 100 can be a geometric phase transmission type metasurface structure, a transmission phase transmission type metasurface structure, or other metasurface structures capable of phase, amplitude, or polarization control. The metasurface substrate can be glass, quartz, or other transparent substrate materials. The nanoscale control structure can be cubic, cuboid, cylindrical, or other subwavelength nanostructures, with microstructure unit sizes ranging from 100 to 800 nm and unit spacing from 300 to 500 nm. The nanoscale control structure material can be crystalline silicon or amorphous silicon. The overall size of the metasurface can be 300 to 1000 μm and can be fabricated using micro / nano fabrication methods such as photolithography and etching. In specific designs, the metasurface can be divided into multiple spatial regions according to display requirements, with each region loading a different target image. The region division can be done using continuous block regions, column-by-column multiplexing, alternate-column multiplexing, or other methods, encoding different target images within the same display area.

[0030] In some embodiments, a region mask function can be used to describe the spatial distribution of different control regions in the metasurface structure layer 100. For the k-th control region, its region mask function... It can be represented as:

[0031] in, This represents the spatial extent of the k-th control region within the metasurface structure layer 100, where 1 represents... Position-controlled nanostructures are applied, where 0 represents The location-controlled nanostructure has not been applied. Two or more controllable regions can be distributed in a continuous blocky pattern, alternating rows and columns, a checkerboard pattern, a random sparse distribution, or a multi-scale nested distribution. For any nanostructure location... The corresponding phase encoding function can be determined based on the control region to which it belongs.

[0032] In this way, the metasurface itself provides high-density holographic information storage and light field reconstruction capabilities, laying the foundation for subsequent dynamic switching.

[0033] The electronically controlled switch layer 200 has multiple electronically controlled switches arranged in an array. The electronically controlled switch layer 200 is divided into two or more switch regions, and each switch region has multiple electronically controlled switches. The multiple switch regions correspond one-to-one with multiple control regions.

[0034] In some embodiments, for example, a polymer-dispersed liquid crystal layer can be prepared on the metasurface structure layer 100 by a polymerization-initiated phase separation method to form an electrically controlled switch layer 200. Specifically, a pre-fabricated liquid crystal cell is fixed to the metasurface substrate with a transparent curing adhesive. A single-phase homogeneous mixture of prepolymer solution and liquid crystal is formed and filled into the pre-fabricated liquid crystal cell. Then, liquid crystal microdroplets are dispersed in the polymer network by heating, ultraviolet light irradiation, or free radical-induced polymerization to form a polymer-dispersed liquid crystal layer. The prepolymer can be NOA65 ultraviolet curing adhesive, and the liquid crystal can be E7 or E63. The ratio of prepolymer to liquid crystal can be 7:3 to 9:1. A microcircuit system is provided on the pre-fabricated liquid crystal cell. This microcircuit system can be patterned according to the structure of different regions or channels of the metasurface. For example, when the metasurface uses 3×3 partition coding, the microcircuit system can also be set with 3×3 independently controllable circuit regions; when the metasurface uses alternating column coding, the microcircuit system can be grouped and controlled according to odd and even columns. When unpowered, the polymer-dispersed liquid crystal is in a highly scattering state, making it difficult for incident light to effectively penetrate the liquid crystal layer and enter the corresponding control region, resulting in the target image being either off or weakly displayed. When a driving voltage is applied, the orientation of the liquid crystal molecules changes, the device becomes transparent, and the incident light can pass through the liquid crystal layer and modulate the nanostructure of the corresponding control region, thereby reconstructing the target image. In a preferred embodiment, the polymer-dispersed liquid crystal layer is located on the optical path before the incident light enters the metasurface structure layer 100, allowing the incident light to pass through the polymer-dispersed liquid crystal layer before reaching the corresponding control region. When the liquid crystal layer is transparent, the incident light can reach the metasurface and be modulated to form the target image; when the liquid crystal layer is in a scattering state, the incident light cannot effectively reach the corresponding control region, resulting in the target image being either off or weakly displayed.

[0035] When the electronically controlled switch layer 200 controls the k-th switch region, a switch passthrough function can be used. This represents its transparent state at time t, where It can be a binary function or a continuous grayscale function. When When it is close to 1, it indicates that the k-th switching region is in an on or high-transmittance state; when When the value is close to 0, it indicates that the k-th switching region is in a closed or low-transmission state.

[0036] Therefore, at time t, the emitted complex amplitude after the metasurface structure layer 100 and the electrically controlled switch layer 200 are... It can be represented as:

[0037] in, Let K represent the incident light field, and K represent the number of target images or control regions. When only the k-th switch region is turned on, the incident light mainly passes through the control region corresponding to that switch region and is encoded by the phase of that control region. The k-th target image is reconstructed; when two or more switch areas are opened simultaneously, the synchronous display or overlay display of two or more target images can be realized; when two or more switch areas are opened sequentially according to a preset time sequence, the dynamic switching or animation display of the target images can be realized.

[0038] Specifically, when no driving voltage is applied, the liquid crystal droplets in the polymer-dispersed liquid crystal layer are randomly oriented, and there is a refractive index mismatch between the liquid crystal droplets and the polymer network. When the incident light passes through the polymer-dispersed liquid crystal layer, it is scattered, which reduces the effective coherent light intensity reaching the corresponding control region, thereby putting the target image corresponding to the control region in a closed, weakly displayed, or background suppressed state.

[0039] When a driving voltage is applied to the corresponding switching region, the liquid crystal molecules in the liquid crystal droplets undergo an orientation change under the influence of the electric field, causing the equivalent refractive index of the liquid crystal droplets to match the refractive index of the polymer network. The polymer-dispersed liquid crystal layer then switches from a scattering state to a transparent state. At this point, incident light can reach the corresponding control region with high transmittance and be modulated by the nanostructures within that region, thereby reconstructing the corresponding target image on the plane containing the target image.

[0040] Since the polymer-dispersed liquid crystal layer mainly changes whether the incident light can effectively enter the corresponding control region, without changing the shape, size, arrangement or phase encoding result of the nano-control structure in the metasurface structure layer 100, the dependence of dynamic control on the tunability of the micro / nano structure itself can be reduced, thereby improving the stability and manufacturability of the device structure.

[0041] The technical solution provided by this invention addresses the problems of existing metasurface control devices, such as difficulty in achieving dynamic control, fixed display content, and unadjustable response speed. It combines the high-density optical field control capabilities of the electrically controlled switch layer 200 and the metasurface structure layer 100, transforming the static, fixed control method of the metasurface structure into a dynamically controllable, switchable, and tunable display. Compared to the control method of traditional spatial light modulators, the technical solution provided by this invention utilizes the advantages of small size, high spatial resolution, and large information capacity of metasurface microstructure units, improving the integration of optical field control and the capacity of optical information channels, and avoiding the problems of large pixel size, limited field of view, and multi-level diffraction in traditional spatial light modulators. Compared to traditional static metasurface optical field control methods, the technical solution provided by this invention introduces an electrically controlled switch layer 200 above the metasurface to enable and disable different control areas, thereby achieving dynamic holographic display. It does not require altering the micro / nano structure of the metasurface structure layer 100 during use; instead, the electrically controlled switch layer 200 adjusts whether light enters or passes through the corresponding control area, thus simplifying the control method and making the structure implementation more direct.

[0042] As an optional implementation method, such as Figure 2 As shown, each of the control regions includes multiple control sub-regions, and each control sub-region includes one or more rows / columns of the nano-control structure. The control sub-regions of two or more control regions are arranged alternately.

[0043] As an optional implementation method, such as Figure 2 As shown, the metasurface structure layer 100 is divided into sub-control regions by alternating columns. For example, multiple control sub-regions of one control region are encoded as an image of a butterfly with its wings fully extended, while multiple control sub-regions of another control region are encoded as an image of a butterfly with its wings closed. By alternately driving the corresponding switching regions, different columns of switching regions are made to transmit light sequentially and participate in the reconstruction of the corresponding images, thus achieving the dynamic animation effect of the butterfly wings opening and closing. In this embodiment, when encoding two images, each sub-control region can use a single column or a single row, or it can use two or more columns or two or more rows. Figure 2 The example uses two columns as a sub-control area.

[0044] As an optional implementation, each of the control regions includes multiple control sub-regions, and each control sub-region includes N M nanostructures, wherein the sub-regions of two or more control regions are arranged alternately in both row and column directions, wherein N and M are both not less than 1.

[0045] In some embodiments, each sub-control region forms a rectangular region, and multiple sub-control regions form a control region. These multiple sub-control regions are arranged alternately in both row and column directions. For example, in the row direction, a cyclical arrangement of sub-control regions from the first control region to the nth control region is formed, and similarly, a cyclical arrangement of sub-control regions from the first control region to the nth control region is formed in the column direction. As a preferred embodiment, when the number of control regions is two, the two or more control regions will form a checkerboard arrangement.

[0046] As an optional implementation method, such as Figure 3 As shown, each control region includes N M of the nanostructures, wherein both N and M are not less than 1.

[0047] As an optional implementation method, such as Figure 3 As shown, the metasurface structure layer 100 can be divided into 3×3 control regions, each loaded with a different English letter. Correspondingly, the electronically controlled switch layer 200 is also set as 3×3 switch regions. By applying driving signals to the switch regions respectively, the display of one or more specific letters can be controlled, thereby realizing dynamic holographic display at different spatial positions.

[0048] As an optional implementation, each of the control regions includes multiple nanostructures, and the nanostructures in two or more control regions are randomly and sparsely distributed.

[0049] In some embodiments, by distributing the nanostructures included in different control regions in a random and sparse manner, the impact of specific location limitations on the display of the target image can be reduced, resulting in a clearer display of the target image.

[0050] As an optional implementation, two or more control regions correspond to the target image at two or more scales, wherein the nanoscale control structures of the two or more control regions are distributed in a multi-scale nested manner.

[0051] In some embodiments, for a multi-scale nested distribution, the unapplied area within the target image range at a larger scale can be used as the display area of ​​the target image at a smaller scale.

[0052] As an optional implementation, the electronically controlled switch layer 200 includes an array of polymer-dispersed liquid crystals, which are fixed by prepolymer polymerization.

[0053] As an optional implementation, the electronically controlled switch layer 200 further includes a driving electrode. The driving electrode adopts a matrix addressing structure and has two or more driving regions. The two or more driving regions correspond one-to-one with two or more switching regions, so as to drive the polymer-dispersed liquid crystal in the corresponding switching region to undergo a state change through the voltage change of the driving region.

[0054] In some embodiments, the liquid crystal driving electrodes adopt a matrix addressing structure to achieve independent control at the region level, column level, row level or pixel level, thereby realizing real-time switching, dynamic display and video display functions of multiple control regions on the target image.

[0055] As an optional implementation, it also includes: The control module is electrically connected to the electronically controlled switch layer 200. The control module controls two or more switch areas according to a preset timing sequence so that the two or more switch areas are opened and closed according to the preset timing sequence.

[0056] In some embodiments, the control system includes a signal generator, a power amplifier, and a microcircuit system connected to the polymer-dispersed liquid crystal. The control module can be formed using existing control module methods, requiring only independent control of each switching region. During control, a square wave or sine wave AC signal is first generated using the signal generator, with a frequency of 1~1000Hz; then, the signal amplitude is expanded to 10~50V by the power amplifier; finally, the amplified AC signal is applied to the microcircuit system of the polymer-dispersed liquid crystal, causing the liquid crystal layer of the corresponding region or channel to switch between a transparent state and a scattering state. By changing the loading area, loading timing, frequency, and voltage amplitude of the driving signal, it is possible to control whether different control regions participate in the reconstruction of the target image, and also to control the switching speed between different target images. Therefore, it is possible not only to open and close static holographic images, but also to achieve dynamic switching of multiple images and simple animation display.

[0057] This invention also provides a method for controlling the optical field of a dynamic metasurface, which is achieved by controlling any of the aforementioned dynamic metasurface optical field control elements. The method includes: According to a preset timing sequence, two or more switching areas in the electronically controlled switch layer 200 are controlled to open according to the preset timing sequence. When the light source passes through the corresponding switching area and the corresponding control area, it is controlled by the control area to form a target image, thus forming a dynamic display of multiple target images by multiple control areas.

[0058] In various embodiments of the present invention, during dynamic display, a laser is used to irradiate the integrated device of the electrically controlled switching layer 200 (i.e., polymer-dispersed liquid crystal) and the metasurface structure layer 100. An electrical signal is applied to the polymer-dispersed liquid crystal by a control system, causing the target switching region to switch from a scattering state to a transparent state. After passing through this region, the incident light is modulated by the control region of the metasurface structure layer 100 to form a corresponding holographic image. Regions where no electrical signal is applied remain in a scattering state, and the corresponding holographic image is not displayed or its display intensity is significantly reduced. Dynamic metasurface holographic display can be achieved by timing control of multiple regions or multiple channels.

[0059] In the foregoing embodiments of the present invention, the metasurface structure layer 100, the electrically controlled switch layer 200, and the control module have a clear functional division and collaborative relationship. The metasurface structure layer 100 is responsible for providing high-resolution holographic phase encoding of the target image; the electrically controlled switch layer 200 is responsible for selectively opening or closing the incident light path in different control regions; and the control module is responsible for driving different switching regions with electrical signals according to a preset timing sequence. With the cooperation of these three components, the spatial information of the target image is stored in the metasurface structure layer 100, and the temporal switching of the target image is achieved by the electrically controlled switch layer 200 and the control module.

[0060] Compared to schemes that directly use spatial light modulators to display holographic images, the embodiments of the present invention do not require real-time refreshing of the complete phase map during the display process. Instead, they utilize the phase encoding already embedded in the metasurface structure layer 100 for image reconstruction, thus improving device integration and reducing system size. Compared to traditional static metasurface holographic devices, the present invention selectively selects different control regions through the electrically controlled switching layer 200, enabling the same metasurface structure layer 100 to display more than two target images, thereby overcoming the problem of fixed content displayed by static metasurfaces. Compared to dynamic metasurface schemes that directly tune the nanoscale control structures themselves, the dynamic process of the present invention mainly occurs in the electrically controlled switching layer 200, eliminating the need to apply independent control signals to each nanoscale control structure individually, thus reducing driving complexity and fabrication difficulty.

[0061] Therefore, the present invention can address the problem that it is difficult to simultaneously achieve high resolution, high information capacity and dynamic control in existing solutions, and provides a technical solution that is simple in structure, easy to integrate, regionally addressable, and suitable for multi-image dynamic holographic display.

[0062] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A dynamic metasurface optical field modulation element, characterized in that, include: A metasurface structure layer having multiple nanoscale control structures arranged in an array, the metasurface structure layer being divided into two or more control regions, each control region having multiple nanoscale control structures, each control region corresponding to a target image, and the nanoscale control structures within each control region performing phase encoding based on the corresponding target image; The electronically controlled switch layer has multiple electronically controlled switches arranged in an array. The electronically controlled switch layer is divided into two or more switch regions, and each switch region has multiple electronically controlled switches. The multiple switch regions correspond one-to-one with multiple control regions.

2. The dynamic metasurface optical field modulation element according to claim 1, characterized in that, Each of the said regulatory regions includes multiple regulatory sub-regions, and each regulatory sub-region includes one or more rows / columns of the said nano-regulatory structures, with the regulatory sub-regions of two or more said regulatory regions arranged alternately.

3. The dynamic metasurface optical field modulation element according to claim 1, characterized in that, Each of the aforementioned control regions includes multiple control sub-regions, and each control sub-region includes N. M nanostructures, wherein the sub-regions of two or more control regions are arranged alternately in both row and column directions, wherein N and M are both not less than 1.

4. The dynamic metasurface optical field modulation element according to claim 1, characterized in that, Each control zone includes N M of the nanostructures, wherein both N and M are not less than 1.

5. The dynamic metasurface optical field modulation element according to claim 1, characterized in that, Each of the said regulatory regions includes multiple said nano-regulatory structures, and the nano-regulatory structures in two or more said regulatory regions exhibit a random and sparse distribution.

6. The dynamic metasurface optical field modulation element according to claim 1, characterized in that, Two or more control regions correspond to the target image at two or more scales, wherein the nanoscale control structures of the two or more control regions are distributed in a multi-scale nested manner.

7. The dynamic metasurface optical field modulation element according to claim 1, characterized in that, The electronically controlled switch layer includes an array of polymer-dispersed liquid crystals, which are fixed by prepolymer polymerization.

8. The dynamic metasurface optical field modulation element according to claim 7, characterized in that, The electronically controlled switch layer also includes a driving electrode. The driving electrode adopts a matrix addressing structure and has two or more driving regions. The two or more driving regions correspond one-to-one with two or more switching regions, so as to drive the polymer-dispersed liquid crystal in the corresponding switching region to change state through the voltage change of the driving region.

9. The dynamic metasurface optical field modulation element according to claim 1, characterized in that, Also includes: A control module is electrically connected to the electronically controlled switch layer. The control module controls two or more switch areas according to a preset timing sequence, so that the two or more switch areas are opened and closed according to the preset timing sequence.

10. A method for dynamically controlling the optical field of a metasurface, characterized in that, The method is achieved by controlling the dynamic metasurface optical field modulation element according to any one of claims 1-9, and includes: According to a preset timing sequence, two or more switching areas in the electronically controlled switch layer are controlled to open according to the preset timing sequence. When the light source passes through the corresponding switching area and the corresponding control area, it is controlled by the control area to form a target image, thus forming a dynamic display of multiple target images by multiple control areas.

Images