Metasurface optical modulator and display device

Abstract

The application relates to a metasurface optical modulator and a display device, which comprises a substrate, a first electrode, a hydrophobic layer, a metasurface array layer, a medium layer, a second electrode and a cover plate, the first electrode is located on one side of the substrate; the hydrophobic layer is located on the side of the first electrode away from the substrate; the metasurface array layer is located on the side of the hydrophobic layer away from the first electrode; the medium layer is located on the side of the metasurface array layer away from the hydrophobic layer, the medium layer comprises at least two kinds of media, the at least two kinds of media have different refractive indexes, and under the action of different voltages, the at least two kinds of media can switch the positions of the two kinds of media relative to the metasurface array layer to adjust the coverage of the two kinds of media on the metasurface array layer; the second electrode is located on the side of the medium layer away from the metasurface array layer; and the cover plate is located on the side of the second electrode away from the medium layer. In this way, the refractive index of light is adjusted by changing the coverage of the two kinds of media on the metasurface array layer, and then the dynamic regulation and control of the focal length of incident light is realized.

Description

Technical Field

[0001] This application relates to the field of optical lens technology, and in particular to a metasurface optical modulator and display device. Background Technology

[0002] Metasurfaces are planar optical elements composed of subwavelength-scale nanoantenna arrays. They can precisely control the physical properties of incident light, such as amplitude, phase, and polarization. They offer advantages such as being thin, easy to integrate, and able to eliminate phase differences.

[0003] However, current metasurface structures have a fundamental flaw: once the design is completed through semiconductor processes, the morphology and size of the nanostructure of the metasurface structure are fixed, and its optical functions (such as focal length, deflection angle, and spectral response) are also solidified, making dynamic tuning impossible.

[0004] Therefore, to solve the above problems, traditional metasurface structure focusing is achieved by installing a mechanical device (MEMS, microelectromechanical system) under the structure to change the tilt angle of the metasurface structure. However, the equipment used in traditional focusing methods is large, heavy, and slow in response. Summary of the Invention

[0005] Therefore, it is necessary to provide a metasurface optical modulator and display device to address the problem that traditional mechanical focusing has a slow response speed and cannot quickly achieve dynamic tuning.

[0006] The first aspect of this application provides a metasurface optical modulator, comprising:

[0007] Base;

[0008] The first electrode is located on one side of the substrate;

[0009] A hydrophobic layer is located on the side of the first electrode opposite to the substrate;

[0010] A metasurface array layer is located on the side of the hydrophobic layer opposite to the first electrode;

[0011] A dielectric layer is located on the side of the metasurface array layer away from the hydrophobic layer. The dielectric layer includes at least two media with different refractive indices. Under different voltages, the at least two media can switch their positions relative to the metasurface array layer to adjust the coverage of the at least two media on the metasurface array layer.

[0012] The second electrode is located on the side of the dielectric layer opposite to the metasurface array layer;

[0013] A cover plate is located on the side of the second electrode opposite to the dielectric layer.

[0014] In one embodiment, the at least two media include a first medium and a second medium, the first medium and the second medium are immiscible, and the first medium and the second medium form a layer and are distributed between the second electrode and the metasurface array layer;

[0015] The first medium is a conductive medium, and the second medium is an insulating medium.

[0016] In one embodiment, the first medium has a first refractive index, the second medium has a second refractive index, and the first refractive index is greater than the second refractive index.

[0017] In one embodiment, the difference between the first refractive index and the second refractive index is greater than or equal to 0.4.

[0018] In one embodiment, the first refractive index is 1.7 to 1.9.

[0019] In one embodiment, the second refractive index is 1.28 to 1.3.

[0020] In one embodiment, the first medium is located on the side closer to the second electrode, and the second medium is located on the side closer to the metasurface array layer.

[0021] In one embodiment, the first medium includes a deionized solution, sodium chloride, ethylene glycol, and titanium dioxide nanoparticles.

[0022] The second medium includes a perfluorinated carbon solution.

[0023] In one embodiment, the metasurface array layer includes multiple array units with different heights, the multiple array units are arranged in an array, and adjacent array units are spaced apart.

[0024] A second aspect of this application provides a display device including the metasurface optical modulator described in the first aspect of this application.

[0025] This application provides a metasurface optical modulator and display device. By setting a dielectric layer comprising a first medium and a second medium with different refractive indices, and applying a voltage to an electrode layer to drive the two media to undergo an electrowetting effect, the coverage of the two media on the metasurface array layer is changed. This process dynamically alters the effective dielectric environment around the metasurface array units, causing the refractive index for light to change synchronously, thereby achieving dynamic control of the incident light focal length. Simultaneously, it eliminates the traditional bulky mechanical focusing structure, enabling device thinning and improved response speed. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of dynamic focusing of a metasurface optical modulator according to an embodiment of this application.

[0027] Figure 2 This is a schematic diagram showing the positions of the first focal point, the first medium, and the second medium of a metasurface optical modulator according to an embodiment of this application when the voltage is 0V.

[0028] Figure 3 This is a schematic diagram showing the positions of the second focal point, the first medium, and the second medium of a metasurface optical modulator according to an embodiment of this application when the voltage is 15V.

[0029] Figure 4 This is a schematic diagram showing the positions of the first and second media when the voltage of a metasurface optical modulator according to an embodiment of this application is 30V.

[0030] Figure 5 This is a schematic diagram illustrating an application scenario of a metasurface optical modulator according to an embodiment of this application.

[0031] Explanation of reference numerals in the attached figures

[0032] 100, Substrate; 110, First Surface;

[0033] 200. First electrode;

[0034] 300. Hydrophobic layer;

[0035] 400. Metasurface array layer; 410. Array unit;

[0036] 500, dielectric layer; 510, first dielectric; 520, second dielectric;

[0037] 600, Second electrode;

[0038] 700, cover plate; 710, second surface;

[0039] 800. Display device; 900. Projected image;

[0040] a) First focus; b) Second focus. Detailed Implementation

[0041] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application will be described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0042] Furthermore, where the terms "first" and "second" appear, these terms are for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined with "first" or "second" may explicitly or implicitly include at least one feature. In the description of this application, where the term "multiple" appears, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0043] like Figures 1 to 4 As shown in the embodiment of this application, a metasurface optical modulator is provided. The metasurface optical modulator includes a substrate 100, a first electrode 200, a hydrophobic layer 300, a metasurface array layer 400, a dielectric layer 500, a second electrode 600, and a cover plate 700 arranged sequentially from bottom to top.

[0044] The substrate 100 has a first surface 110, and the cover plate 700 has a second surface 710, with the first surface 110 and the second surface 710 disposed opposite to each other. A first electrode 200 is located on one side of the first surface 110 of the substrate 100, and a hydrophobic layer 300 is located on the side of the first electrode 200 away from the substrate 100. The hydrophobic layer 300 is a thin film with hydrophobic properties covering the surface of the first electrode 200, which can promote dielectric movement under electrowetting effect. A metasurface array layer 400 is located on the side of the hydrophobic layer 300 away from the first electrode 200. A dielectric layer 500 is located on the side of the metasurface array layer 400 away from the hydrophobic layer 300, and a second electrode 600 is located on the side of the dielectric layer 500 away from the metasurface array layer 400. The second electrode 600 is connected to the second surface 710 of the cover plate 700, and the first electrode 200 and the second electrode 600 cooperate to apply a driving voltage.

[0045] Furthermore, the dielectric layer 500 includes at least two dielectrics with different refractive indices. Under different voltages, the positions of the two dielectrics relative to the metasurface array layer 400 can be switched to adjust their coverage of the metasurface array layer 400. Thus, by changing the relative coverage areas of the two dielectrics on the metasurface array layer 400, the refractive index environment of the metasurface array layer 400 can be dynamically and continuously changed.

[0046] Specifically, when a voltage is applied between the first electrode 200 and the second electrode 600, the voltage acts on the dielectric in the dielectric layer 500. Since at least two dielectrics within the dielectric layer 500 have different electrical properties (such as conductivity and insulation), driven by the electrowetting effect, at least one of the dielectrics moves relative to the metasurface array layer 400 under the influence of the voltage. This movement of the dielectric changes the coverage area (i.e., coverage rate) of the metasurface array layer 400 by the dielectrics with different refractive indices. Therefore, when light propagates in the metasurface array layer 400, the coverage rate of at least two dielectrics on the metasurface array layer 400 can be controlled by adjusting the voltage. This allows for dynamic and continuous modulation of the phase distribution of the incident light by the metasurface array layer 400, thereby achieving optical modulation functions such as focal length adjustment. Furthermore, the entire optical modulation process does not require the use of mechanical moving parts, achieving high-speed and non-mechanical dynamic optical modulation. It also solves the problems of large device size, heavy weight, and slow response speed caused by the functional solidification of traditional metasurfaces and reliance on mechanical focusing.

[0047] It is understandable that this optical modulator, by employing the electrowetting effect, can drive a relative positional change of at least two media within the dielectric layer 500 relative to the metasurface array layer 400. The model formula for the electrowetting effect is as follows:

[0048] ,

[0049] in, The contact angle after applying voltage; The initial contact angle is V; V is the applied voltage. The surface tension coefficient of the liquid; It is the vacuum permittivity; It is the relative permittivity; The thickness is the dielectric layer.

[0050] In some embodiments, the dielectric layer 500 includes at least two dielectrics, namely a first dielectric 510 and a second dielectric 520. The first dielectric 510 and the second dielectric 520 are immiscible, and the first dielectric 510 and the second dielectric 520 are layered and distributed between the second electrode 600 and the hydrophobic layer 300. Thus, the immiscibility of the first dielectric 510 and the second dielectric 520 ensures that a clear and stable physical boundary can be maintained between the first dielectric 510 and the second dielectric 520.

[0051] Specifically, the first medium 510 is a conductive medium, and the second medium 520 is an insulating medium. By distinguishing between conductive and insulating media, when a voltage is applied to the dielectric layer 500 through the first electrode 200 and the second electrode 600, the voltage can effectively act on the first medium 510 (conductive medium), thereby inducing a change in interfacial tension (i.e., electrowetting effect) and driving the first medium 510 to displace relative to the second medium 520 (insulating medium). Since the second medium 520 is insulating, its electrical state is largely unaffected by the voltage, and it primarily acts as the object of displacement. Therefore, through the cooperation of the first medium 510 and the second medium 520, it is possible to ensure that the coverage of the metasurface array layer 400 by the first medium 510 and the second medium 520 dynamically changes under the electrowetting driving mechanism.

[0052] In some embodiments, the first medium 510 has a first refractive index, the second medium 520 has a second refractive index, and the first refractive index is greater than the second refractive index. Additionally, the refractive index of the metasurface array layer 400 is approximately 2.4, and the refractive index difference in the switching state is greater than or equal to 0.4. The switching state includes an on state and a off state. When in the on state, the input voltage is 0V; when in the off state, the input voltage is greater than 0V. Regardless of whether in the on or off state, the difference between the first refractive index of the first medium 510 and the second refractive index of the second medium 520 is greater than or equal to 0.4.

[0053] Therefore, by setting the aforementioned refractive index difference, it can be ensured that when the coverage of the two media on the metasurface array layer 400 changes, the effective refractive index of the environment surrounding the array unit 410 can change significantly enough, thereby enabling the optical modulator to achieve a noticeable change in focal length. If the refractive index difference between the two media is too small, the modulation effect will be weak and the change will be insignificant.

[0054] In some embodiments, the first refractive index of the first medium 510 is 1.7 to 1.9, and the second refractive index of the second medium 520 is 1.28 to 1.3.

[0055] Specifically, regarding the specific composition of the first medium 510 and the second medium 520 mentioned above, the first medium 510 is formed by mixing a deionized solution, sodium chloride, ethylene glycol water, and titanium dioxide nanoparticles; the second medium 520 is a perfluorinated carbon solution.

[0056] More specifically, according to the refractive index tuning formula for mixed liquids:

[0057] ,

[0058] in, The equivalent refractive index after mixing; , The volumes of the first medium 510 and the second medium 520 are respectively. , represents the refractive index of the first medium 510 and the second medium 520.

[0059] Therefore, the first medium 510 is suitable for use with deionized water as the base solvent, wherein it contains 5% by mass sodium chloride, 10% by mass ethylene glycol, and 5% by mass titanium dioxide nanoparticles. Sodium chloride is used to provide ionic conductivity, ethylene glycol is used to adjust viscosity and prevent particle agglomeration and sedimentation, and the titanium dioxide nanoparticles are dispersed and mixed therein to modulate the refractive index of the formed first medium 510 to approximately 1.8. Furthermore, cesium chloride (CsCl) can be added to the above mixed solution to fine-tune the density of the first medium 510 to 1.85 g / cm³.

[0060] Furthermore, the second medium 520 is suitable as a solution of perfluorinated carbon, with a refractive index of approximately 1.29 and a density of approximately 1.85 g / cm³. The second medium 520 formed from the perfluorinated carbon solution is chemically stable and immiscible with the first medium 510. Thus, by making the densities of the first medium 510 and the second medium 520 similar and ensuring their immiscibility, the potential problem of stratification instability due to gravity after mixing the first medium 510 and the second medium 520 is eliminated.

[0061] In some embodiments, regarding the initial relative positions of the first medium 510 and the second medium 520 mentioned above, the first medium 510 is located on the side closer to the second electrode 600 and is in contact with the second electrode 600, while the second medium 520 is located on the side closer to the hydrophobic layer 300 and can cover the metasurface array layer 400. After voltage is applied, the first medium 510 moves relative to the second medium 520 under the action of voltage to compress the second medium 520 towards the second electrode 600. At this time, a gap is generated between the second medium 520 and the hydrophobic layer 300, and the first medium 510 can quickly fill the gap between the second medium 520 and the hydrophobic layer 300.

[0062] In the initial state (without applying voltage to the first medium 510 and the second medium 520), the insulating second medium 520 stably covers the array units 410 of the metasurface array layer 400 due to its affinity with the hydrophobic layer 300. When a voltage is applied, due to the electrowetting effect, the interfacial tension of the first medium 510 in contact with the second electrode 600 changes, causing it to tend to move towards the hydrophobic layer 300. As the first medium 510 moves, it squeezes the second medium 520 that originally occupied the space, thereby causing the second medium 520 to separate from the surface of the hydrophobic layer 300 and partially detach from the array unit 410 until the second medium 520 is completely detached from the array unit 410 and moves towards the second electrode 600. Therefore, the first medium 510 penetrates and fills the gap between the second medium 520 and the hydrophobic layer 300 in the early stage of separation of the second medium 520 and the hydrophobic layer 300, until the positions of the second medium 520 and the first medium 510 are completely interchanged, thereby realizing the dynamic adjustment of the coverage of the metasurface array layer 400 by the first medium 510 and the second medium 520.

[0063] In some embodiments, the metasurface array layer 400 includes a plurality of array units 410 with different heights, arranged in an array with adjacent array units 410 spaced apart. The array units 410 with different heights can produce different inherent phase delays for light. It is understood that the metasurface array layer 400 is a planar optical structure formed by arranging the array units 410 on a two-dimensional plane. The array units 410 with different heights are arranged in a specific sequence on the plane to control the incident light. The spacing between the array units 410 provides space for the dielectric in the subsequent dielectric layer 500 to wet and cover the array units 410.

[0064] For example, the array units 410 of different heights are nanopillars, wherein the height of the low nanopillars can be set to 1 micrometer and the height of the high nanopillars can be set to 2 micrometers. It can be understood that when the liquid level of the second medium 520 is 0.5 micrometers, the coverage of the second medium 520 for the low nanopillars is 50% and the coverage of the high nanopillars is 75%.

[0065] Specifically, the model formula for the optical characteristics of array unit 410 is as follows, which describes the effect of the liquid level height of the second medium 520 on the focal length:

[0066] ,

[0067] in, is a function of liquid height; r is the radial coordinate; The refractive index of the material of array unit 410; The refractive index of the second medium 520; H(r) is the refractive index of the first medium 510; H(r) is the height distribution function of the array element 410. The first derivative of the height distribution function of array cell 410; To obtain the minimum value between the liquid level height and the column height; Let r be the partial derivative of r; r=0 is the value at the center position.

[0068] like Figure 2 As shown, in the initial state (e.g., the voltage is 0V), the second medium 520 with low refractive index completely covers the array unit 410, that is, the coverage of the second medium 520 for the array unit 410 at different heights is 100%. At this time, the light passes through each medium and the metasurface array layer 400 in the optical modulator to form the first focal point a. In this state, it is suitable for users with low myopia to view clear images.

[0069] like Figure 3 As shown, when a change in user refractive power is detected (e.g., switching users), a specific loading voltage (e.g., 15V) is applied to the first electrode 200 and the second electrode 600. Under this voltage, the conductive first dielectric 510 moves towards the hydrophobic layer 300 driven by the electrowetting effect, and squeezes the second dielectric 520 close to the hydrophobic layer 300, thereby partially replacing the second dielectric 520 originally covering the array units 410 of the metasurface array layer 400. This causes the coverage of the second dielectric 520 on the array units 410 to decrease from 100% (e.g., the coverage of the second dielectric 520 on low nanopillars is 50%, and the coverage of high nanopillars is 75%). With the dynamic change in coverage, after light enters the dielectric layer 500, the path changes from the original path of entering the first dielectric 510-second dielectric 520-array unit 410 to entering the first dielectric 510-second dielectric 520-first dielectric 510-array unit 410. Furthermore, by changing the effective refractive index of light around the array unit 410, the phase modulation amount of light produced by the metasurface array layer 400 changes, forming a second focal point b. Thus, by continuously adjusting the focal length of the optical modulator to match the user's diopter, adaptive focal length adjustment of the optical modulator is achieved.

[0070] like Figure 4 As shown, a specific loading voltage (e.g., 30V) is applied to the first electrode 200 and the second electrode 600, at which point the first dielectric 510 achieves 100% coverage of the array elements 410 at different heights. Under this voltage, the optical modulator is suitable for scenarios requiring a long focal length.

[0071] In some embodiments, the first electrode 200 and the second electrode 600 are used to apply voltage to the first dielectric 510 and the second dielectric 520, and the second dielectric 520 is adapted to separate from the hydrophobic layer 300 during the voltage application process and move toward the second electrode 600. Simultaneously, the first dielectric 510 fills the gap created after the separation of the second dielectric 520 and the hydrophobic layer 300. At this time, the coverage of the second dielectric 520 over the plurality of array units 410 gradually decreases.

[0072] Specifically, when a voltage is applied between the first electrode 200 and the second electrode 600, the first dielectric 510 expands towards the hydrophobic layer 300 under the influence of the voltage. However, since the total volume of the first dielectric 510 and the second dielectric 520 is constant and immiscible, the expansion of the first dielectric 510 inevitably compresses the second dielectric 520, forcing it to separate from the area in contact with the hydrophobic layer 300 and the sidewall of the array unit 410. Subsequently, the second dielectric 520 moves towards the second electrode 600 under the compression of the first dielectric 510. During this movement, the coverage area of ​​the second dielectric 520 over the array unit 410 gradually decreases, meaning the coverage rate of the second dielectric 520 over the array unit 410 gradually decreases. Correspondingly, the coverage rate of the first dielectric 510 over the array unit 410 gradually increases. Therefore, after light enters the first dielectric 510 and the second dielectric 520, the change in the coverage rate of the different media over the array unit 410 causes a synchronous change in the refractive index, ultimately resulting in a dynamic change in the focal length following the change in refractive index.

[0073] It should be noted that the substrate 100 and the cover plate 700 can be made of transparent materials such as glass or polymers. The first electrode 200 and the second electrode 600 can be made of transparent conductive oxides such as indium tin oxide (ITO). The hydrophobic layer 300 can be made of fluorinated polymers. The array units 410 of the metasurface array layer 400 can be fabricated from high refractive index dielectric materials such as gallium nitride (GaN), titanium dioxide (TiO2), or amorphous silicon (a-Si) using semiconductor micro-nano fabrication processes (such as electron beam lithography and reactive ion etching), and their height can be designed to be between several hundred nanometers and several micrometers.

[0074] Specifically, the dielectric layer 500 is sealed within the cavity formed by the first electrode 200, the hydrophobic layer 300, the second electrode 600, and the sidewalls. The overall thickness of the optical modulator can be less than 10 micrometers. Furthermore, the response time of the optical modulator can reach the millisecond level (e.g., about 1 ms), which is much smaller than the conventional 50 ms response speed.

[0075] More specifically, under 532nm wavelength light irradiation, by varying the voltage (e.g., from 0V to 30V) driving the first electrode 200 and the second electrode 600, the refractive index of the optical modulator can be varied from approximately 35% to approximately 93%, achieving a modulation depth of 58%. Furthermore, the densities of the first dielectric 510 and the second dielectric 520 can be tuned to be approximately equal (e.g., both approximately 1.85 g / cm³). 3 This enhances the operational stability of the optical modulator and prevents the liquid interface from tilting due to gravity.

[0076] like Figure 5 As shown in the embodiments of this application, a display device 800 is also provided, which includes a metasurface optical modulator as described in any of the above embodiments. This display device 800 (such as AR glasses or VR headsets) integrates a metasurface optical modulator to dynamically and rapidly adjust the optical focal length of the modulator by controlling the voltage and according to the user's visual parameters (such as diopter) or the needs of the displayed content. This achieves adaptive clear imaging at different distances or for users with different visual acuity, thereby improving the visual comfort and user experience of the display device 800.

[0077] It is understood that when integrating optical modulators into augmented reality (AR) glasses, the focal length control equation of electrically adjustable lenses must be followed:

[0078] ,

[0079] in, Real-time focal length; Reference voltage; Reference voltage The focal length below; The voltage-refractive sensitivity coefficient can be obtained through device calibration. This is the real-time input voltage.

[0080] Therefore, for a refractive power of D eye Users can calculate the required voltage V according to the above formula, causing the metasurface to generate the corresponding optical refractive power, thereby projecting the image 90° onto the user's retina to achieve adaptive visual correction. For traditional metasurface structure focusing, focusing is achieved by installing mechanical devices (MEMS, microelectromechanical systems, etc.) below the structure to change the tilt angle of the metasurface structure. Traditional focusing methods involve large, heavy, and slow-responding devices. However, using the optical modulator described in any of the above embodiments of this application for focusing results in a lighter overall structure, faster response, and lower power consumption.

[0081] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0082] It should be noted that if a component is described as "fixed to" or "set on" another component, it can be directly on the other component or there may be an intervening component. If a component is described as "connected to" another component, it can be directly connected to the other component or there may be an intervening component.

[0083] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A metasurface optical modulator, characterized in that, include: Substrate (100); The first electrode (200) is located on one side of the substrate (100); A hydrophobic layer (300) is located on the side of the first electrode (200) away from the substrate (100); A metasurface array layer (400) is located on the side of the hydrophobic layer (300) opposite to the first electrode (200); A dielectric layer (500) is located on the side of the metasurface array layer (400) away from the hydrophobic layer (300). The dielectric layer (500) includes at least two media with different refractive indices. Under different voltages, the at least two media can switch their positions relative to the metasurface array layer (400) to adjust the coverage of the at least two media on the metasurface array layer (400). The second electrode (600) is located on the side of the dielectric layer (500) opposite to the metasurface array layer (400); A cover plate (700) is located on the side of the second electrode (600) away from the dielectric layer (500).

2. The metasurface optical modulator according to claim 1, characterized in that, The at least two media include a first medium (510) and a second medium (520), the first medium (510) and the second medium (520) are immiscible, and the first medium (510) and the second medium (520) form a layer and are distributed between the second electrode (600) and the metasurface array layer (400); The first medium (510) is a conductive medium, and the second medium (520) is an insulating medium.

3. The metasurface optical modulator according to claim 2, characterized in that, The first medium (510) has a first refractive index, and the second medium (520) has a second refractive index, wherein the first refractive index is greater than the second refractive index.

4. The metasurface optical modulator according to claim 3, characterized in that, The difference between the first refractive index and the second refractive index is greater than or equal to 0.

4.

5. The metasurface optical modulator according to claim 4, characterized in that, The first refractive index is 1.7 to 1.

9.

6. The metasurface optical modulator according to claim 4, characterized in that, The second refractive index is 1.28 to 1.

3.

7. The metasurface optical modulator according to claim 2, characterized in that, The first medium (510) is located on the side closer to the second electrode (600), and the second medium (520) is located on the side closer to the metasurface array layer (400).

8. The metasurface optical modulator according to claim 2, characterized in that, The first medium (510) includes a deionized solution, sodium chloride, ethylene glycol, and titanium dioxide nanoparticles; The second medium (520) comprises a perfluorinated carbon solution.

9. The metasurface optical modulator according to claim 1, characterized in that, The metasurface array layer (400) includes multiple array units (410) with different heights, the multiple array units (410) are arranged in an array, and adjacent array units (410) are spaced apart.

10. A display device, characterized in that, Includes the metasurface optical modulator as described in any one of claims 1 to 9.

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