Flexible metasurface and dynamic holographic multiplexing method based on flexible metasurface

Abstract

The invention belongs to the technical field of micro-nano optics, and discloses a flexible metasurface and a dynamic holographic multiplexing method based on the flexible metasurface. The flexible metasurface provided by the invention comprises a flexible substrate and a metasurface functional region located on the flexible substrate, the metasurface functional area is integrated with two functional areas which are composed of nano brick arrays and have the same overall size, and marks used for space alignment are arranged on the peripheries of the two functional areas; when the left-hand circularly polarized light enters the flexible substrate and independently passes through the first functional area and the second functional area, a first far-field hologram and a second far-field hologram are respectively generated; the flexible substrate is folded along the central axis of the two functional areas, and after spatial alignment is achieved based on the marks, the two functional areas are oppositely arranged on the two sides of the flexible substrate; and when the left-hand circularly polarized light enters the folded and aligned metasurface, a third far-field hologram is generated. A feasible scheme is provided for application of the dynamic metasurface, and the dynamic wavefront regulation and control requirement can be met.

Description

Technical Field

[0001] The present invention belongs to the field of micro-nano optical technology, and more specifically, relates to a flexible supersurface and a dynamic holographic multiplexing method based on the flexible supersurface. Background Art

[0002] As one of the most revolutionary breakthroughs in micro-nano photonics in the 21st century, metasurfaces have shown breakthrough technological potential in the field of electromagnetic wave control. This artificially designed two-dimensional functional material achieves precise control of light wavefront parameters by periodically arraying sub-wavelength-scale nanostructure units (i.e., metaatoms) on the substrate surface. Compared with traditional bulk optical devices, metasurfaces have core advantages such as ultra-thin geometric configurations (thickness less than the working wavelength), low-profile characteristics, and multi-dimensional light field control capabilities (coordinated control of amplitude, phase, polarization state, and angular momentum). Its unique electromagnetic response characteristics provide key functional devices for the new generation of photonic integrated circuits, large-capacity optical communication systems, and high-density optical storage technologies, and are promoting the leapfrog development of modern optical engineering towards integration and intelligence.

[0003] However, due to the high intrinsic stiffness of the material, traditional rigid substrate metasurfaces can only achieve static light field control after the structure is finalized, which is difficult to meet the technical requirements of dynamic wavefront control. Therefore, exploring the dynamic control scheme of the phase of flexible metasurfaces has become a core topic that needs to be broken through in this research field. Summary of the invention

[0004] The present invention solves the problem that the metasurface in the prior art can only realize static light field control by providing a flexible metasurface and a dynamic holographic multiplexing method based on the flexible metasurface.

[0005] The present invention provides a flexible metasurface, comprising: a flexible substrate, and a metasurface functional region located on the flexible substrate; the metasurface functional region integrates two functional regions both consisting of nanobrick arrays and having the same overall size, and the peripheries of the two functional regions are both provided with marks for spatial alignment;

[0006] When left-handed circularly polarized light is incident on the flexible substrate and passes through the first functional area, a first far-field hologram is generated;

[0007] When left-handed circularly polarized light is incident on the flexible substrate and passes through the second functional area, a second far-field hologram is generated;

[0008] The flexible substrate is folded along the central axis of the two functional areas, and after spatial alignment is achieved based on the marks, the two functional areas are arranged relatively on two sides of the flexible substrate;

[0009] When left-handed circularly polarized light is incident on the folded and aligned metasurface, a third far-field hologram is generated.

[0010] Preferably, the flexible substrate is made of polydimethylsiloxane or polyimide.

[0011] Preferably, at the working wavelength, the nanobricks in both functional regions are used to achieve the function of a half-wave plate.

[0012] Preferably, the nanobrick arrays included in the two functional regions have the same periodic size, and several nanobricks included in the two functional regions have the same geometric size; the periodic size and the geometric size of the nanobricks are determined according to the working wavelength and the target polarization conversion efficiency;

[0013] According to the first far-field hologram, the second far-field hologram, and the third far-field hologram, the angular arrangement of the nanobricks is determined.

[0014] Preferably, the first functional region acts on the incident left-handed circularly polarized light as:

[0015]

[0016] The second functional region acts on the incident left-handed circularly polarized light as:

[0017]

[0018] The metasurface after folding and alignment acts on the incident left-handed circularly polarized light as:

[0019]

[0020] In the formula, θ1 is the rotation angle of the nanobricks in the first functional region, and θ2 is the rotation angle of the nanobricks in the second functional region.

[0021] Preferably, the GS algorithm is used to optimize the phase distribution of the two functional regions to determine the angular arrangement of the nanobricks.

[0022] Preferably, according to the working wavelength and the target polarization conversion efficiency, the materials for preparing the nanobricks in the two functional regions are selected.

[0023] Preferably, the same one material or two different materials are selected for the two functional regions to prepare the nanobricks, and the materials for preparing the nanobricks are selected from single-crystalline silicon, polycrystalline silicon, or titanium dioxide.

[0024] Preferably, the flexible substrate is divided into a plurality of unit structures with the same size. The working surface of the unit structure is square, and the nano-brick array includes a plurality of nano-bricks. One unit structure in the metasurface functional region and one nano-brick located on the working surface of the unit structure constitute a nano-unit structure, and the size of the nano-unit structure is sub-wavelength scale.

[0025] On the other hand, the present invention provides a dynamic holographic multiplexing method based on the above flexible metasurface, including:

[0026] Incident left-handed circularly polarized light on the flexible substrate of the flexible metasurface and pass through the first functional region to generate a first far-field hologram; incident left-handed circularly polarized light on the flexible substrate and pass through the second functional region to generate a second far-field hologram.

[0027] Fold the flexible substrate along the central axis of the two functional regions, and after achieving spatial alignment based on the marks, arrange the two functional regions on both sides of the flexible substrate relatively; incident left-handed circularly polarized light on the folded and aligned metasurface to generate a third far-field hologram.

[0028] One or more technical solutions provided in the present invention have at least the following technical effects or advantages:

[0029] The flexible metasurface provided by the present invention includes a flexible substrate and a metasurface functional region located on the flexible substrate. The metasurface functional region integrates two functional regions both composed of nano-brick arrays and having the same overall size. Marks for spatial alignment are provided on the peripheries of the two functional regions. When left-handed circularly polarized light is incident on the flexible substrate and passes through the first functional region, a first far-field hologram is generated; when left-handed circularly polarized light is incident on the flexible substrate and passes through the second functional region, a second far-field hologram is generated. After folding the flexible substrate along the central axis of the two functional regions and achieving spatial alignment based on the marks, the two functional regions are arranged on both sides of the flexible substrate relatively. When left-handed circularly polarized light is incident on the folded and aligned metasurface, a third far-field hologram is generated. Based on the above flexible metasurface, the present invention also provides a corresponding dynamic holographic multiplexing method, including: incident left-handed circularly polarized light on the flexible substrate of the flexible metasurface and pass through the first functional region to generate a first far-field hologram; incident left-handed circularly polarized light on the flexible substrate and pass through the second functional region to generate a second far-field hologram; fold the flexible substrate along the central axis of the two functional regions, and after achieving spatial alignment based on the marks, arrange the two functional regions on both sides of the flexible substrate relatively; incident left-handed circularly polarized light on the folded and aligned metasurface to generate a third far-field hologram. That is, the present invention can realize three-channel hologram display by combining the folding characteristics of the flexible substrate, providing a feasible solution for the application of dynamic metasurfaces and meeting the technical requirements of dynamic wavefront control. Brief Description of the Drawings

[0030] Figure 1 Schematic diagram of a flexible metasurface provided in Embodiment 1 of the present invention;

[0031] Figure 2 Schematic diagram of the polarization conversion efficiency of Region 1 of a flexible metasurface provided in Embodiment 1 of the present invention versus wavelength;

[0032] Figure 3 Target image of Region 1 of a flexible metasurface provided in Embodiment 1 of the present invention;

[0033] Figure 4 Simulation result of the Fourier hologram generated by Region 1 of a flexible metasurface provided in Embodiment 1 of the present invention;

[0034] Figure 5 Schematic diagram of the polarization conversion efficiency of Region 2 of a flexible metasurface provided in Embodiment 1 of the present invention versus wavelength;

[0035] Figure 6 Target image of Region 2 of a flexible metasurface provided in Embodiment 1 of the present invention;

[0036] Figure 7 Simulation result of the Fourier hologram generated by Region 2 of a flexible metasurface provided in Embodiment 1 of the present invention;

[0037] Figure 8 Target image of a flexible metasurface provided in Embodiment 1 of the present invention after folding and alignment;

[0038] Figure 9 Simulation result of the Fourier hologram generated by a flexible metasurface provided in Embodiment 1 of the present invention after folding and alignment. Detailed Embodiments

[0039] In order to better understand the above technical solutions, the above technical solutions will be described in detail below in conjunction with the accompanying drawings of the specification and specific embodiments.

[0040] Embodiment 1:

[0041] Embodiment 1 provides a flexible metasurface, including: a flexible substrate, and a metasurface functional region located on the flexible substrate; the metasurface functional region integrates two functional regions both composed of nano-brick arrays and having the same overall size, and marks for spatial alignment are arranged on the peripheries of the two functional regions; when left-handed circularly polarized light is incident on the flexible substrate and passes through the first functional region, a first far-field hologram is generated; when left-handed circularly polarized light is incident on the flexible substrate and passes through the second functional region, a second far-field hologram is generated; the flexible substrate is folded along the central axis of the two functional regions, and after spatial alignment is achieved based on the marks, the two functional regions are arranged oppositely on both sides of the flexible substrate; when left-handed circularly polarized light is incident on the folded and aligned metasurface, a third far-field hologram is generated.

[0042] Wherein, the flexible substrate is divided into a plurality of unit structures with the same size, the working surface of the unit structure is square, and the nano-brick array includes a plurality of nano-bricks; one unit structure in the metasurface functional region and one nano-brick located on the working surface of the unit structure form a nano-unit structure, and the size of the nano-unit structure is sub-wavelength level.

[0043] At the working wavelength, the nano-bricks in the two functional regions are both used to realize the function of a half-wave plate.

[0044] The nano-brick arrays included in the two functional regions have the same periodic size, and the several nano-bricks included in the two functional regions have the same geometric size; according to the working wavelength and the target polarization conversion efficiency, the periodic size and the geometric size of the nano-bricks are determined; according to the first far-field hologram, the second far-field hologram and the third far-field hologram, the angular arrangement of the nano-bricks is determined.

[0045] For example, the GS algorithm can be used to optimize the phase distribution of the two functional regions to determine the angular arrangement of the nano-bricks.

[0046] In addition, according to the working wavelength and the target polarization conversion efficiency, materials for preparing the nano-bricks in the two functional regions are selected. Among them, the same one material or two different materials are selected for the two functional regions to prepare the nano-bricks, and the materials for preparing the nano-bricks are selected from single-crystalline silicon, polycrystalline silicon or titanium dioxide. For example, the first functional region selects single-crystalline silicon material, and the second functional region selects polycrystalline silicon. The material type only affects the difference in the nano-brick structure size in order to obtain the maximum polarization conversion efficiency.

[0047] See Figure 1, in the present invention, two metasurface functional regions with the same unit period and overall size are integrated on the top surface of the flexible substrate. For example, these two functional regions (denoted as Region 1 and Region 2) are arranged collinearly along the row direction through a cross fiducial marking system. Both functional regions are encoded using the geometric phase modulation principle. When incident with left-handed circularly polarized light, they independently generate corresponding transmissive Fourier holographic projections. In particular, by performing a 180° flipping operation on the flexible substrate around the symmetry axis of the two functional regions (which can also be understood as folding the flexible substrate along the central axis of the two functional regions), and achieving precise spatial alignment based on the cross fiducial marking, Region 1 and Region 2 can be respectively located on the front and back sides of the substrate structure. This three-dimensional spatial reconstruction device architecture innovatively realizes a multiple holographic superposition effect, enabling the metasurface to perform real-time regulation on the incident left-handed circularly polarized light wavefront, and ultimately generating a third-order Fourier far-field holographic projection with dynamic modulation capabilities. The design of the present invention effectively improves the functional integration and optical response dimension of the metasurface device.

[0048] The following further illustrates the present invention with examples in combination with parameters.

[0049] The flexible substrate can be prepared from flexible materials such as polydimethylsiloxane (PDMS) and polyimide (PI).

[0050] The metasurface units of the first functional region (i.e., Region 1) adopt a phase-type hologram functional architecture, and a single-crystalline silicon material system is selected to construct the subwavelength structure. The metasurface operates in the mode of perpendicular incidence of left-handed circularly polarized light, and the target wavelength is 550 nm. The structural parameters are set as follows: the height of the nanobrick is 220 nm, and the periodic size of the functional region is 300 nm. Based on the CST Studio Suite electromagnetic simulation platform, parametric modeling and optimization analysis are carried out for the aspect ratio parameter of the nanobrick to obtain the optimal polarization conversion efficiency. After multi-objective optimization, the best geometric parameters are determined as: the length of the nanobrick is 250 nm, and the width is 25 nm. This configuration achieves a polarization conversion efficiency of 78.6%, meeting the requirements of phase modulation performance. Its electromagnetic response characteristics are verified by strict time-domain simulation, conforming to the design specification requirements. The schematic diagram of the polarization conversion efficiency of Region 1 versus wavelength is as Figure 2 shown.

[0051] The GS (Gerchberg-Saxton) algorithm is used to optimize the phase distribution of Region 1. Set the number of pixels of Region 1 to 1000×1000, the size of Region 1 to 300 um×300 um, and the diffraction distance of the Fourier hologram to 5 cm, meeting the far-field condition, and generate a grayscale image of the letter 'A' (i.e., the first far-field hologram). Assume a random phase as the initial phase distribution of Region 1, combined with a unit amplitude, the initial wavefront function can be obtained The wavefront function on the image plane can be obtained by using the forward Fresnel diffraction integral Preserve the phase Replace the amplitude with the light wave amplitude distribution f on the diffraction image plane. At this time, the new image plane wave function becomes After obtaining the new image plane wave function U2, use the backward Fresnel diffraction formula to obtain the wavefront function of Region 1 Preserve the phase Remain unchanged, replace the amplitude with the unit amplitude 1, that is, the complex amplitude becomes As the initial object wave function for the next iteration loop, through repeated iterative calculation operations until the maximum number of iterations is reached or the set root mean square error reaches the predetermined accuracy. At this time, the final phase Is the phase of Region 1, where 100 is the number of iterations

[0052] The nanobricks in the first functional region can realize the function of a half-wave plate. The first functional region acts on the incident left-handed circularly polarized light The action is expressed as:

[0053]

[0054] In the formula, θ1 is the rotation angle of the nanobricks in the first functional region. After passing through Region 1, the left-handed circularly polarized light undergoes phase modulation by the metasurface and becomes right-handed circularly polarized light, and the phase modulation amount is twice the rotation angle of the nanobricks in Region 1

[0055] Using the relationship between the geometric phase of the metasurface and the rotation angle of the nanobricks: It is obtained that the rotation angle of each unit pixel nanobrick is half of the phase of the pixel. Using the previously selected nanobrick structure for arrangement, the metasurface nanobrick array pattern of Region 1 is obtained. Among them, the target image of Region 1 is as Figure 3 Shown, the simulation result of the Fourier hologram generated by Region 1 is as Figure 4 Shown

[0056] The metasurface part of the second functional region (i.e., Region 2) also realizes the phase-type Fourier holographic phase function. Consistent with the nanounit structure of Region 1 mentioned above, it is selected that the incident left-handed circularly polarized light is incident perpendicular to the flexible substrate, the working wavelength is 550 nm, the period size is 300 nm, the length and width of the rectangular nanobricks are 250 nm and 25 nm respectively, so as to obtain the highest polarization conversion efficiency, and single crystal silicon is selected as the nanobrick material. The schematic diagram of the polarization conversion efficiency of Region 2 versus wavelength is as Figure 5 Shown

[0057] Similarly, the GS (Gerchberg-Saxton) algorithm is used to iteratively optimize the phase of Region 2. When the number of iterations reaches 100 or the preset accuracy of the root mean square error is satisfied, the phase distribution of Region 2 is finally determined.

[0058] The nanobricks in the second functional region can achieve the function of a half-wave plate. The action of the second functional region on the incident left-handed circularly polarized light is expressed as:

[0059]

[0060] In the formula, θ2 is the rotation angle of the nanobricks in the second functional region. After passing through Region 2, the left-handed circularly polarized light undergoes phase modulation by the metasurface and becomes right-handed circularly polarized light, and the phase modulation amount is twice the rotation angle of the nanobricks in Region 2.

[0061] Using the relationship between the geometric phase of the metasurface and the rotation angle of the nanobricks: It is obtained that the rotation angle of the nanobricks of each unit pixel is half of the phase of that pixel. Using the previously selected nanobrick structure for arrangement, the metasurface nanobrick array pattern of Region 2 is obtained. Among them, the target image of Region 2 is as Figure 6 shown, and the simulation result of the Fourier hologram generated by Region 2 is as Figure 7 shown.

[0062] After folding along the central axes of Region 1 and Region 2 and aligning through the cross marks near the two metasurfaces, Region 1 and Region 2 are arranged opposite to each other on both sides of the substrate and merged into a whole.

[0063] The action of the folded and aligned metasurface on the incident left-handed circularly polarized light is expressed as:

[0064]

[0065] In the formula, θ1 is the rotation angle of the nanobricks in the first functional region, and θ2 is the rotation angle of the nanobricks in the second functional region. After the left-handed circularly polarized light undergoes double modulation by the metasurfaces of Region 2 and Region 1, the outgoing light is left-handed circularly polarized light, and the phase modulation amount is twice the sum of the rotation angles of the nanobricks in Region 1 and Region 2. Among them, the target image of the folded and aligned flexible metasurface is as Figure 8 shown, and the simulation result of the Fourier hologram generated after the flexible metasurface is folded and aligned is as Figure 9 shown.

[0066] When designing the flexible metasurface, an xoy coordinate system is established with the two right-angled sides of the nano-unit structure as the x-axis and y-axis. The working wavelength of the incident circularly polarized light is selected, and the material of the nano-bricks is selected. Based on the working wavelength and the material of the nano-bricks, electromagnetic simulation software is used for modeling and simulation. When the rotation angles of the nano-bricks in Region 1 and Region 2 are both 0, linearly polarized light with polarization directions along the x-axis and y-axis respectively is incident perpendicularly. Taking the transmittance of the two kinds of linearly polarized light emitted being greater than the preset value and the phase difference being 180° as the optimization object (to achieve the function of a half-wave plate, that is, the polarization conversion efficiency reaches the maximum), at the working wavelength, the size parameters of the nano-unit structure are optimized so that the nano-bricks in Region 1 and Region 2 are both equivalent to half-wave plates (the preset transmittance value is 0.5).

[0067] When using electromagnetic simulation software for modeling and simulation, the information obtained includes: the transmission coefficients of the nano-bricks in Region 1 for linearly polarized light with polarization directions along the x-axis and y-axis, the phase modulation values of the nano-bricks in Region 1 for linearly polarized light with polarization directions along the x-axis and y-axis, the transmission coefficients of the nano-bricks in Region 2 for linearly polarized light with polarization directions along the x-axis and y-axis, and the phase modulation values of the nano-bricks in Region 2 for linearly polarized light with polarization directions along the x-axis and y-axis.

[0068] The nano-bricks in the two functional regions of the flexible metasurface provided in Example 1 can both achieve the function of a half-wave plate. Circularly polarized light is incident on the flexible substrate layer and passes through the nano-brick array layer in Region 1 to generate a first far-field hologram such as the letter A. The circularly polarized light with the opposite sense of rotation to the incident circularly polarized light in the emitted light is phase-modulated; circularly polarized light is incident on the flexible substrate layer and passes through the nano-brick array layer in Region 2 to generate a second far-field hologram such as the letter B. The circularly polarized light with the opposite sense of rotation to the incident circularly polarized light in the emitted light is phase-modulated; circularly polarized light is incident on the overall metasurface structure of Region 2 and Region 1 to generate a third far-field hologram such as the letter C. The circularly polarized light with the same sense of rotation as the incident circularly polarized light in the emitted light is phase-modulated. In Example 1, without changing the nano-structure size and without increasing the unit structure size, continuous and precise phase modulation can be achieved only by changing the rotation angle of the nano-structure, and it is convenient for processing. The nano-unit structure sizes in Example 1 are all sub-wavelength levels, so the metasurface is small in volume, light in weight, and can be highly integrated, adapting to the future development of miniaturization and micro-miniaturization. The foldable flexible metasurface proposed in Example 1 can achieve dynamic holographic switching, greatly improving the metasurface multiplexing ability, providing a new idea for multi-dimensional information storage of the metasurface, and providing a feasible solution for the application of dynamic metasurfaces.

[0069] Example 2:

[0070] Embodiment 2 provides a dynamic holographic multiplexing method based on the flexible metasurface described in Embodiment 1, including:

[0071] Using left - hand circularly polarized light to be incident on the flexible substrate of the flexible metasurface and pass through the first functional region to generate a first far - field hologram; using left - hand circularly polarized light to be incident on the flexible substrate and pass through the second functional region to generate a second far - field hologram.

[0072] Fold the flexible substrate along the central axis of the two functional regions, and after achieving spatial alignment based on the marks, arrange the two functional regions relatively on both sides of the flexible substrate; use left - hand circularly polarized light to be incident on the folded and aligned metasurface to generate a third far - field hologram.

[0073] That is, Embodiment 2 uses the flexible metasurface provided in Embodiment 1 to achieve dynamic holographic multiplexing.

[0074] Since the dynamic holographic multiplexing method provided in Embodiment 2 corresponds to the structural functions of the flexible metasurface provided in Embodiment 1, Embodiment 2 can be understood by referring to the description of Embodiment 1, and will not be elaborated here.

[0075] Finally, it should be noted that the above - mentioned specific embodiments are only used to illustrate the technical solutions of the present invention rather than to limit them. Although the present invention has been described in detail with reference to the examples, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the spirit and scope of the technical solutions of the present invention, and they should all be covered within the scope of the claims of the present invention.

Claims

1. A flexible metasurface, characterized in that, Comprising: A flexible substrate, and a metasurface functional region located on the flexible substrate; the metasurface functional region integrates two functional regions both composed of nanobrick arrays and having the same overall size, and marks for spatial alignment are provided on the peripheries of the two functional regions; When left-handed circularly polarized light is incident on the flexible substrate and passes through the first functional region, a first far-field hologram is generated; When left-handed circularly polarized light is incident on the flexible substrate and passes through the second functional region, a second far-field hologram is generated; The flexible substrate is folded along the central axis of the two functional regions, and after achieving spatial alignment based on the marks, the two functional regions are arranged oppositely on both sides of the flexible substrate; When left-handed circularly polarized light is incident on the folded and aligned metasurface, a third far-field hologram is generated.

2. The flexible metasurface according to claim 1, wherein The flexible substrate is prepared from polydimethylsiloxane or polyimide.

3. The flexible metasurface according to claim 1, wherein, At the working wavelength, the nanobricks in the two functional regions are both used to realize the function of a half-wave plate.

4. The flexible metasurface according to claim 1, wherein The nanobrick arrays included in the two functional regions have the same periodic size, and several nanobricks included in the two functional regions have the same geometric size; the periodic size and the geometric size of the nanobricks are determined according to the working wavelength and the target polarization conversion efficiency; According to the first far-field hologram, the second far-field hologram, and the third far-field hologram, the angular arrangement of the nanobricks is determined.

5. The flexible metasurface according to claim 4, characterized in that, The action of the first functional region on the incident left-handed circularly polarized light is expressed as: The action of the second functional region on the incident left-handed circularly polarized light is expressed as: The folded and aligned metasurface's effect on incident left-handed circularly polarized light is expressed as: In the formula, θ1 is the rotation angle of the nanobricks in the first functional region, and θ2 is the rotation angle of the nanobricks in the second functional region.

6. The flexible metasurface according to claim 5, wherein, The GS algorithm is used to optimize the phase distribution of the two functional regions to determine the angular arrangement of the nanobricks.

7. The flexible metasurface according to claim 4, wherein According to the working wavelength and the target polarization conversion efficiency, the materials for preparing the nanobricks in the two functional regions are selected.

8. The flexible metasurface according to claim 7, wherein, The same one material or two different materials are selected for the two functional regions to prepare the nanobricks, and the materials for preparing the nanobricks are selected from single-crystalline silicon, polycrystalline silicon, or titanium dioxide.

9. The flexible metasurface according to claim 1, wherein The flexible substrate is divided into multiple unit structures with the same size. The working surface of the unit structure is square, and the nanobrick array includes several nanobricks; one unit structure in the metasurface functional region and one nanobrick located on the working surface of the unit structure form a nano-unit structure, and the size of the nano-unit structure is sub-wavelength level.

10. A dynamic holographic multiplexing method based on the flexible metasurface according to any one of claims 1-9, characterized in that, Comprising: Using left-handed circularly polarized light to be incident on the flexible substrate of the flexible metasurface and passing through the first functional region to generate a first far-field hologram; Using left-handed circularly polarized light to be incident on the flexible substrate and passing through the second functional region to generate a second far-field hologram; Folding the flexible substrate along the central axis of the two functional regions, and after achieving spatial alignment based on the marks, arranging the two functional regions oppositely on both sides of the flexible substrate; Using left-handed circularly polarized light to be incident on the folded and aligned metasurface to generate a third far-field hologram.

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