Arrayed deformable liquid crystal elastomer terahertz modulation metasurface and preparation method thereof

Abstract

The embodiment of the application discloses an arrayed deformation liquid crystal elastomer terahertz modulation super surface and a preparation method thereof. The super surface comprises a liquid crystal elastomer substrate and a super surface structure on one side of the substrate, the super surface structure comprises a plurality of open resonant rings; a plurality of terahertz modulation units, the terahertz modulation unit comprises at least one open resonant ring; and a hollow area arranged on the liquid crystal elastomer substrate and extending in a line shape, the line connecting the two ends of the hollow area extends along a first direction, and the liquid crystal elastomer substrate in the terahertz modulation unit is connected with the whole liquid crystal elastomer substrate at the position of the line. The technical scheme of the embodiment of the application uses the terahertz modulator composed of the liquid crystal elastomer substrate and the super surface structure on the substrate, locally excites the deformation of the substrate by applying the structure light to the liquid crystal elastomer, directly regulates and controls each unit structure of the terahertz super surface, and thus the modulation effect on the transmission / reflection terahertz spectrum is realized.

Description

Technical Field

[0001] This invention relates to the field of terahertz modulator technology, and in particular to an arrayed deformable liquid crystal elastomer terahertz modulation metasurface and its preparation method. Background Technology

[0002] Metasurfaces, as two-dimensional artificial electromagnetic structures, can compactly adjust the amplitude, phase, and polarization state of electromagnetic waves, achieving high-degree-of-freedom manipulation of electromagnetic waves. Metasurfaces composed of subwavelength artificial atoms offer advantages in electromagnetic field modulation that traditional functional devices cannot match. The subwavelength-scale micro-planar structures significantly reduce the size of optical systems, increase design freedom, and facilitate integration. The application range of metasurface devices already covers microwaves, terahertz waves, infrared, and visible light. Compared to metallic metasurfaces in the visible light band, metallic metasurfaces exhibit significantly lower ohmic losses in the terahertz band, resulting in superior performance. Furthermore, they can be fabricated using mature micron-scale photolithography and various metal deposition techniques, meeting the prerequisites for large-scale production. Specifically, in terms of spectral modulation, by utilizing the different response characteristics of metallic metasurfaces to the electric and magnetic components of electromagnetic fields, the frequency spectrum of emitted terahertz waves can be efficiently and compactly controlled in real time, enabling planar, compact terahertz modulators.

[0003] However, because the electrical conductivity of metals is not easily affected by external terahertz waves, most terahertz metallic metasurfaces are passive devices. To address this issue, various functional materials have been introduced as substrates for metasurfaces, including semiconductors (such as n-type gallium arsenide layers), superconductors (such as yttrium barium copper oxide), phase change materials (such as vanadium dioxide), and liquid crystals. By applying external light, heat, or electricity to the substrate, the substrate's electrical conductivity or refractive index and other properties can be altered, thereby controlling the response of the metasurface.

[0004] In recent years, mechanical manipulation has also attracted much attention. Compared with the previously mentioned methods of changing the substrate's structural parameters, mechanical manipulation has the advantages of wide bandwidth and large change range. Liquid crystal elastomers have significant advantages in this direction. Combining the network elasticity of polymers and the anisotropic characteristics of liquid crystals, liquid crystal elastomers are mainly used in soft robotics and artificial muscles. In recent years, the application potential of liquid crystal elastomers in the optical field has been gradually discovered. Their actuable properties have begun to be utilized to deposit conductive materials on surfaces, leading to preliminary research on tunable optical applications. Liquid crystal elastomers based on carbon nanostructures and other nanomaterials have been widely used in microelectromechanical systems (MEMS). The reversible mechanical deformation of liquid crystal elastomers can be excited by light, electricity, magnetism, and heat; this property can be well integrated with metasurfaces.

[0005] The thermal deformation capability of liquid crystal elastomers, combined with micro-nano fabrication technology, allows for the fabrication of metasurface structures using liquid crystal elastomers as substrates, giving the metasurfaces mechanical tunability. However, the control methods for liquid crystal elastomers have not yet achieved localization and precision. Currently, only active control of light beam transmittance has been achieved, and precise control of the metal structure in the unit to achieve spectrum modulation has not yet been realized. Summary of the Invention

[0006] This invention provides an arrayed deformable liquid crystal elastomer terahertz modulation metasurface and its fabrication method. The structure uses a terahertz modulator composed of a liquid crystal elastomer substrate and a metasurface structure located on the substrate. By applying structured light to the liquid crystal elastomer to locally excite the deformation of the substrate, the direct control of each unit structure of the terahertz metasurface is achieved, thereby realizing the modulation effect of the transmission / reflection terahertz spectrum.

[0007] According to one aspect of the present invention, an arrayed deformable liquid crystal elastomer terahertz modulation metasurface is provided, comprising a liquid crystal elastomer substrate and a metasurface structure located on one side of the liquid crystal elastomer substrate, the metasurface structure comprising a plurality of open resonant rings arranged in an array;

[0008] Multiple terahertz modulation units arranged in an array, each terahertz modulation unit including at least one of the aforementioned open-loop resonant rings;

[0009] The terahertz modulation unit further includes a cutout area disposed on the liquid crystal elastomer substrate and extending in a linear shape. The cutout area at least partially surrounds the open resonant ring in the terahertz modulation unit. The connecting line between the two ends of the cutout area extends along a first direction. The liquid crystal elastomer substrate in the terahertz modulation unit is integrally connected to the liquid crystal elastomer substrate at the position of the connecting line.

[0010] The first direction is parallel to the plane containing the liquid crystal elastomer substrate.

[0011] Optionally, the terahertz modulation unit includes a frequency hopping modulation unit, which includes four open resonant rings arranged in a 2×2 array. Along the second direction, the openings of two open resonant rings in the same frequency hopping modulation unit are arranged opposite to each other.

[0012] The first direction and the second direction intersect.

[0013] Optionally, the position where the terahertz modulation unit is connected to the liquid crystal elastomer substrate is excited by driving light, so as to raise the local temperature of the liquid crystal elastomer substrate and control the bending of the liquid crystal elastomer to achieve terahertz modulation.

[0014] Optionally, the driving light includes lattice structured light emitted from a lens optical system or a digital micromirror device.

[0015] Optionally, the aperture resonant ring includes a square aperture resonant ring, the projection of the frequency hopping modulation unit onto the plane of the liquid crystal elastomer substrate is rectangular, and the edge of the cutout area coincides with three sides of the rectangle.

[0016] Optionally, the resonant frequency of the split-ring resonator is determined by the following formula:

[0017]

[0018] Where L represents the equivalent inductance of the open resonant ring, and C represents the equivalent capacitance at the opening.

[0019] Optionally, the open-circuit resonant ring includes at least one of a square open-circuit resonant ring, a circular open-circuit resonant ring, a rhomboid open-circuit resonant ring, or a hexagonal open-circuit resonant ring;

[0020] The open resonant ring includes at least one opening.

[0021] Optionally, the liquid crystal elastomer substrate is formed by doping MXene with a liquid crystal polymer composed of two liquid crystal monomers, RM257 and RM006, and Irgacure651 photoinitiator.

[0022] Optionally, the open resonant ring is formed of an aluminum thin film.

[0023] According to another aspect of the present invention, a method for preparing an arrayed deformable liquid crystal elastomer terahertz modulation metasurface is provided, for preparing the above-mentioned arrayed deformable liquid crystal elastomer terahertz modulation metasurface, the method comprising:

[0024] Forming a liquid crystal elastomer substrate;

[0025] A metal thin film is deposited on one side of the liquid crystal elastomer substrate;

[0026] The metal thin film is processed into a metasurface structure using photolithography, the metasurface structure comprising multiple open resonant rings arranged in an array;

[0027] Laser processing is used to create a hollow area around each terahertz modulation unit.

[0028] The arrayed deformable liquid crystal elastomer terahertz modulation metasurface provided in this invention includes a liquid crystal elastomer substrate and a metasurface structure located on one side of the liquid crystal elastomer substrate. The metasurface structure includes multiple arrayed open resonant rings; multiple arrayed terahertz modulation units, each terahertz modulation unit including at least one open resonant ring; each terahertz modulation unit further includes a hollow region disposed on the liquid crystal elastomer substrate and extending linearly, the hollow region at least partially surrounding the open resonant ring within the terahertz modulation unit, the connecting line at both ends of the hollow region extending along a first direction, and the liquid crystal elastomer substrate within the terahertz modulation unit being integrally connected to the liquid crystal elastomer substrate at the position of the connecting line; the first direction is parallel to the plane of the liquid crystal elastomer substrate. By using a terahertz modulator composed of a liquid crystal elastomer substrate and a metasurface structure located on the substrate, and setting a hollow region on the liquid crystal elastomer substrate corresponding to the terahertz modulation unit, deformation occurs when structured light is applied to the liquid crystal elastomer to locally excite the substrate, achieving a modulation effect on the transmitted / reflected terahertz spectrum. Furthermore, each terahertz modulation unit can be controlled by structured light arrays, paving the way for subsequent programmable terahertz spectrum modulation metasurfaces based on liquid crystal elastomers.

[0029] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of the present invention, nor is it intended to limit the scope of the invention. Other features of the invention will become readily apparent from the following description. Attached Figure Description

[0030] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0031] Figure 1 This is a schematic diagram of the structure of an arrayed deformable liquid crystal elastomer terahertz modulation metasurface provided in an embodiment of the present invention;

[0032] Figure 2 This is a schematic diagram of the structure of a terahertz modulation unit provided in an embodiment of the present invention;

[0033] Figure 3 This is a schematic diagram of the shape of an optional open-ended resonant ring according to an embodiment of the present invention;

[0034] Figure 4 This is a schematic diagram illustrating the working principle of a terahertz frequency hopper provided in an embodiment of the present invention.

[0035] Figure 5 This is a schematic diagram of the structural parameters of a square open-loop resonator provided in an embodiment of the present invention;

[0036] Figure 6 A schematic diagram illustrating the frequency hopping effect of a terahertz frequency hopper on an x-polarized terahertz transmitted beam, provided as an embodiment of the present invention;

[0037] Figure 7 This is a schematic flowchart illustrating a method for preparing an arrayed deformable liquid crystal elastomer terahertz modulation metasurface according to an embodiment of the present invention. Detailed Implementation

[0038] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. 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 should fall within the scope of protection of the present invention.

[0039] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0040] For applications of liquid crystal elastomers, Yanlei Yu et al. synthesized a liquid crystal elastomer film using azobenzene chains, achieving bending in the direction of 366nm linearly polarized light irradiation, with the bending direction always parallel to the polarization direction of the light. To restore it to its initial state, it only needs to be irradiated with 540nm visible light, and this process can be repeated multiple times. Liu Li et al. synthesized a series of single-layer biphase liquid crystal elastomer films, which can perform three-dimensional movements such as bending, accordion-like folding, wrinkling, and curling under ultraviolet irradiation and thermal stimulation. Wei-Fan Chiang et al. used conductive metal microstructures deposited on liquid crystal elastomers to achieve continuous control of the transmission intensity of terahertz beams, equivalent to a controllable attenuator in the terahertz band. To avoid overheating and deformation of the liquid crystal elastomer during metal deposition, they designed an electronic switch and cooling system. 450nm pump blue light is used for driving at a 45° angle, and the transmittance of the normally incident terahertz beam increases with the increase of the pump light power. Simultaneously, it can also modulate the resonant frequency of the broadband terahertz beam.

[0041] Most terahertz metallic metasurfaces have fixed properties after forming and cannot be controlled in real time according to changes in external conditions. Reported controllable terahertz metallic metasurfaces mainly rely on changing substrate structural parameters, which have a small controllability range, limited applicability, and strong side effects. Therefore, this invention utilizes the recoverable mechanical deformation capability of liquid crystal elastomers, combined with terahertz metasurfaces and precisely localized external excitation, to provide a new design approach for reconfigurable continuously variable array terahertz spectrum modulators.

[0042] Figure 1 This is a schematic diagram of the structure of an arrayed deformable liquid crystal elastomer terahertz modulation metasurface provided in an embodiment of the present invention. Figure 2 This is a schematic diagram of a terahertz modulation unit provided in an embodiment of the present invention, with reference to... Figure 1 and Figure 2 The arrayed deformable liquid crystal elastomer terahertz modulation metasurface provided in this embodiment includes a liquid crystal elastomer substrate 10 and a metasurface structure 20 located on one side of the liquid crystal elastomer substrate. The metasurface structure 20 includes a plurality of open-ended resonant rings 21 arranged in an array; and a plurality of terahertz modulation units 30 arranged in an array, wherein at least one open-ended resonant ring 21 is located in each terahertz modulation unit 30. Figure 1 and Figure 2(The illustration of four open resonant rings 21 is merely schematic and not a limitation of the embodiments of the present invention); the terahertz modulation unit 30 also includes a hollow region 31 disposed on the liquid crystal elastomer substrate 10 and extending in a linear shape. The hollow region 31 at least partially surrounds the open resonant rings 21 within the terahertz modulation unit 30. The line AB connecting the two ends of the hollow region 31 extends along the first direction x. The liquid crystal elastomer substrate 10 within the terahertz modulation unit 30 is integrally connected to the liquid crystal elastomer substrate 10 at the position of the line AB. The first direction is parallel to the plane where the liquid crystal elastomer substrate 10 is located.

[0043] Among them, the open-loop resonant ring 21 is the most common metal microstructure unit in metasurface structures, and its resonant frequency f can be determined by the following formula using the equivalent RCL circuit analysis method:

[0044]

[0045] Where L represents the equivalent inductance of the open-loop resonant ring, and C represents the equivalent capacitance at the opening.

[0046] The shape of the open-ring resonator 21 can be designed according to the actual situation. Figure 1 and Figure 2 The square shape of the open-ended resonant ring 21 shown is merely illustrative. Optionally, the open-ended resonant ring may include at least one of a square open-ended resonant ring, a circular open-ended resonant ring, a rhomboid open-ended resonant ring, or a hexagonal open-ended resonant ring. The open-ended resonant ring includes at least one opening. In specific implementations, the shape and number of openings of the resonant ring can be selected according to actual conditions, and this embodiment of the invention does not limit this. For example, Figure 3 This is a schematic diagram of the shape of an optional open-ended resonant ring in an embodiment of the present invention, wherein (1) to (15) correspond to an open-ended resonant ring respectively.

[0047] In a specific embodiment, the terahertz modulator is a terahertz frequency hopping device. Optionally, the terahertz modulation unit 30 includes a frequency hopping modulation unit, which includes four open resonant rings 21 arranged in a 2×2 array. Along the second direction y, the openings of two open resonant rings in the same frequency hopping modulation unit are arranged opposite to each other; wherein the first direction x and the second direction y intersect.

[0048] In this embodiment of the invention, a square open resonant ring is selected as the metal microstructure unit of the metasurface. The square open resonant ring is formed by microstructures deposited from aluminum thin film or other good conductors. According to formula (1), to generate the frequency hopping effect, two different resonant frequencies need to be determined. That is, according to the required operating frequency, an array of open resonant rings with two resonant modes needs to be designed so that they are excited by the electric and magnetic components of the incident electromagnetic wave, respectively. Finally, they are repeated and arranged to form a metasurface structure.

[0049] Optionally, the liquid crystal elastomer substrate 10 is formed by doping MXene with a liquid crystal polymer composed of two liquid crystal monomers, RM257 and RM006, and Irgacure651 photoinitiator.

[0050] The active control in this embodiment is achieved through the photothermal driving properties of the liquid crystal elastomer. During the fabrication of the liquid crystal elastomer, 10% by mass of MXene is incorporated to enhance its absorption of 1030nm driving light, thereby improving photothermal conversion efficiency and the response speed of the liquid crystal elastomer to deformation. MXene is a class of two-dimensional inorganic compounds in materials science. These materials consist of transition metal carbides, nitrides, or carbonitrides with a thickness of several atomic layers. First reported in 2011, MXene materials exhibit metallic conductivity due to the presence of hydroxyl groups or terminal oxygen atoms on their surface. Figure 4 This is a schematic diagram illustrating the working principle of a terahertz frequency hopping device according to an embodiment of the present invention. (Refer to...) Figure 4 Optionally, the driving light can be used to excite the connection point between the terahertz modulation unit 30 and the liquid crystal elastomer substrate 10, causing a local temperature increase in the liquid crystal elastomer substrate and controlling the bending of the liquid crystal elastomer to achieve terahertz modulation (frequency hopping). Optionally, the driving light includes a lattice structured light emitted from a lens optical system or a digital micromirror device (DMD). Each light spot will be focused on the area where the terahertz modulation unit 30 is connected to the substrate. The liquid crystal elastomer in the irradiated area absorbs heat and bends, causing the terahertz modulation unit 30 to bend from the plane of the liquid crystal elastomer substrate 10, extending into a third dimension and becoming a three-dimensional metamaterial. Since the degree of deformation of the liquid crystal elastomer substrate 10 can be adjusted by the power density of the driving light, the amplitude of the frequency hopping can achieve a continuously changing process.

[0051] The technical solution of this invention utilizes a terahertz modulator composed of a liquid crystal elastomer substrate and a metasurface structure located on the substrate. A cutout area is formed on the liquid crystal elastomer substrate corresponding to the terahertz modulation unit. When the device is a frequency hopping device, deformation occurs when structured light is applied to the liquid crystal elastomer to locally excite the substrate. The electric and magnetic fields of the electromagnetic wave respectively excite two resonant modes of the metasurface structure, thereby achieving a terahertz spectrum jump. Furthermore, each frequency hopping modulation unit can be controlled using a structured light array, paving the way for subsequent programmable terahertz spectrum modulation metasurfaces based on liquid crystal elastomers. By controlling the power density of the structured light, a single frequency hopping modulation unit of the terahertz frequency hopping device can achieve continuously controllable bending deformation. Since the liquid crystal elastomer can achieve a bending angle of up to 90°, the terahertz frequency hopping device in this invention can achieve a continuous change in electric field amplitude from 0.5V / m to 0.9V / m. Bending of liquid crystal elastomers does not significantly alter their structural parameters in the terahertz band. Therefore, the frequency hopping effect caused by bending is entirely derived from the response of the metasurface structure to electromagnetic waves, and the modulation effect exhibits good frequency stability.

[0052] Continue to refer to Figure 1 or Figure 2 Optionally, the aperture resonant ring 21 includes a square aperture resonant ring, and the projection of the terahertz modulation unit 30 onto the plane of the liquid crystal elastomer substrate 10 is rectangular, with the edge of the cutout area coinciding with three sides of the rectangle. That is, each terahertz modulation unit 30 is connected to the entire liquid crystal elastomer substrate 10 in only one direction. In other embodiments, the aperture resonant ring can be a circular aperture resonant ring, and the cutout area can also be set in an arc shape, which can be designed according to the actual situation in specific implementation.

[0053] In one specific embodiment, the terahertz frequency hopping device sample size is 1.35 × 1.35 cm. 2 Frequency jumps are achieved in the transmitted beam near the target frequencies of 0.35THz and 0.42THz.

[0054] Figure 5 This is a schematic diagram of the structural parameters of a square-aperture resonant ring provided in an embodiment of the present invention. (Reference) Figure 5 In this context, l and g represent the outer side length and opening size of the square open-circuit resonator, respectively, while w and k represent the linewidth of the ring and the spacing between the rings, respectively. The aluminum thin film is deposited with the same thickness of 200 nm, an outer side length l of 75 μm, an opening size g and a ring spacing k of 20 μm, and a linewidth w of 10 μm.

[0055] In this embodiment, the cutting length in the x-direction is 350 μm, the cutting length in the y-direction is 280 μm, and the cutting line width in both directions is 15 μm. Since the metal structure is deposited before laser cutting during sample preparation, target alignment becomes crucial. Using the cross-shaped alignment marks left during metal deposition as a reference for laser cutting allows for accurate positioning and cutting at preset locations. Furthermore, because the design includes a pre-defined distance between the cutting lines and the aluminum structure, the liquid crystal elastomer unit structure can withstand bending deformation without damaging the aluminum structure.

[0056] Furthermore, each unit structure is periodically arranged in the x and y directions, with periods of 450 μm (x-direction) and 380 μm (y-direction), respectively. The thickness of the liquid crystal elastomer material used is 45 μm.

[0057] Figure 6 This is a schematic diagram illustrating the frequency hopping effect of a terahertz frequency hopper on an x-polarized terahertz transmitted beam, provided as an embodiment of the present invention. From... Figure 6 As can be seen, with the gradual increase of the bending angle, a resonance valley gradually appears near 0.35 THz and the transmittance gradually decreases, while the transmittance of the resonance valley near 0.42 THz gradually increases, and the electric field amplitude can achieve a continuous change from 0.5 V / m to 0.9 V / m. The bending angle of the liquid crystal elastomer is proportional to the optical power density of the driving light; therefore, the bending angle of the metasurface can be precisely controlled by adjusting the driving light. That is, when terahertz waves pass through a terahertz frequency hopper, the metasurface is excited at a preset frequency, generating a resonance valley in the transmission spectrum; by applying external driving light, the liquid crystal elastomer deforms, and the resonance mode of the metasurface at another frequency is excited, while the mode at the original frequency is suppressed, thereby achieving real-time control of terahertz frequency transitions.

[0058] The electromagnetic field mode distribution of an x-direction linearly polarized terahertz beam incident perpendicularly to the plane of the substrate at bending angles of 90° and 0° was simulated using the electromagnetic field numerical simulation software CST Microwave Studio. The incident terahertz wave configuration shows that its electric field component is along the x-direction and its magnetic field component is along the y-direction. Electromagnetic resonance is only excited when either the electric or magnetic field direction is perpendicular to the surface of the square open resonant ring. At a bending angle of 90°, the magnetic field component of the terahertz beam passes through the square open resonant ring, exciting an electromagnetic resonance mode at a frequency of 0.3528 THz; while at a bending angle of 0°, the square open resonant ring exhibits another electromagnetic resonance mode excited by the electric field component at 0.4208 THz. At other bending angles within the range of 0° to 90°, the two electromagnetic resonance modes coexist and mutually suppress each other. The liquid crystal elastomer, driven by an external driving light, exhibits a bending angle variation from 0° to 90°, causing the metasurface to produce a frequency-hopping effect on the transmitted terahertz beam.

[0059] Figure 7 This is a schematic flowchart illustrating a method for fabricating an arrayed deformable liquid crystal elastomer terahertz modulation metasurface according to an embodiment of the present invention. The fabrication method provided in this embodiment is used to fabricate the arrayed deformable liquid crystal elastomer terahertz modulation metasurface provided in the above embodiment. (Refer to...) Figure 7 The preparation method provided in this embodiment includes:

[0060] S110, forming a liquid crystal elastomer substrate.

[0061] The process sequence here is as follows: a liquid crystal polymer is composed of two liquid crystal monomers, RM257 and RM006, and an Irgacure 651 photoinitiator. Then, 10% MXene is added by mass, and the polymer is cured by photopolymerization under ultraviolet light. Due to the temperature-sensitive nature of liquid crystal elastomers, strict temperature control is required during the processing to prevent the sample surface from becoming uneven or irreversibly bent due to excessive temperature.

[0062] Optionally, the liquid crystal elastomer substrate is formed on one side of the glass substrate and is peeled off from the glass substrate after the terahertz modulator is fabricated.

[0063] Due to the flexible nature of liquid crystal elastomers, during processing, the liquid crystal elastomers need to be placed on the surface of a glass substrate for support, and after processing, the terahertz modulator with metasurface structure is completely peeled off from the glass substrate.

[0064] S120. A metal thin film is deposited on one side of the liquid crystal elastomer substrate.

[0065] The metal thin film can be an aluminum thin film or a microstructure deposited from other good conductors.

[0066] S130. Using photolithography, a metal thin film is processed into a metasurface structure, which includes multiple open resonant rings arranged in an array.

[0067] The specific process steps are as follows: (1) Spin-coating a layer of positive resist;

[0068] (2) Obtain the metasurface pattern through ultraviolet lithography and development process;

[0069] (3) Use aluminum etching solution to wet etch away the aluminum film outside the open resonant ring;

[0070] (4) The surface resist is removed by the desizing step to obtain an aluminum structure.

[0071] S140: Laser processing is used to create a hollow area around each terahertz modulation unit.

[0072] The arrayed deformable liquid crystal elastomer terahertz modulation metasurface provided in this embodiment is fabricated using mature micron-level photolithography, metal deposition, and laser direct writing techniques. For example, in Figure 1 In the structure shown, laser processing is used to precisely cut around each terahertz modulation unit in three directions to complete the fabrication.

[0073] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. An arrayed deformable liquid crystal elastomer terahertz modulation metasurface, characterized in that, The invention includes a liquid crystal elastomer substrate and a metasurface structure located on one side of the liquid crystal elastomer substrate, wherein the metasurface structure includes a plurality of open resonant rings arranged in an array. Multiple terahertz modulation units arranged in an array, wherein each terahertz modulation unit includes at least one of the open-loop resonant rings; The terahertz modulation unit further includes a hollow area disposed on the liquid crystal elastomer substrate and extending in a linear shape. The hollow area at least partially surrounds the open resonant ring within the terahertz modulation unit. The connecting line between the two ends of the hollow area extends along a first direction. The liquid crystal elastomer substrate within the terahertz modulation unit is integrally connected to the liquid crystal elastomer substrate at the position of the connecting line. The position where the terahertz modulation unit is integrally connected to the liquid crystal elastomer substrate is excited by driving light. The liquid crystal elastomer in the irradiated area absorbs heat and bends, thereby realizing a terahertz frequency jump. The first direction is parallel to the plane containing the liquid crystal elastomer substrate.

2. The arrayed deformable liquid crystal elastomer terahertz modulation metasurface according to claim 1, characterized in that, The terahertz modulation unit includes a frequency hopping modulation unit, which includes four open resonant rings arranged in a 2×2 array. Along the second direction, the openings of two open resonant rings in the same frequency hopping modulation unit are arranged opposite to each other. The first direction and the second direction intersect.

3. The arrayed deformable liquid crystal elastomer terahertz modulation metasurface according to claim 1, characterized in that, The driving light includes lattice structured light emitted from a lens optical system or a digital micromirror device.

4. The arrayed deformable liquid crystal elastomer terahertz modulation metasurface according to claim 2, characterized in that, The aperture resonant ring includes a square aperture resonant ring, and the projection of the frequency hopping modulation unit onto the plane of the liquid crystal elastomer substrate is rectangular, with the edge of the cutout area coinciding with three sides of the rectangle.

5. The arrayed deformable liquid crystal elastomer terahertz modulation metasurface according to claim 1, characterized in that, The resonant frequency of the open-loop resonant ring is determined by the following formula: ； in, L This represents the equivalent inductance of the open-loop resonant ring. C This represents the equivalent capacitance at the opening.

6. The arrayed deformable liquid crystal elastomer terahertz modulation metasurface according to claim 5, characterized in that, The open-loop resonant ring includes at least one of a square open-loop resonant ring, a circular open-loop resonant ring, a rhombic open-loop resonant ring, or a hexagonal open-loop resonant ring; The open resonant ring includes at least one opening.

7. The arrayed deformable liquid crystal elastomer terahertz modulation metasurface according to claim 1, characterized in that, The liquid crystal elastomer substrate is formed by doping MXene with a liquid crystal polymer composed of two liquid crystal monomers, RM257 and RM006, and Irgacure651 photoinitiator.

8. The arrayed deformable liquid crystal elastomer terahertz modulation metasurface according to claim 1, characterized in that, The open resonant ring is formed from an aluminum thin film.

9. A method for preparing an arrayed deformable liquid crystal elastomer terahertz modulation metasurface, characterized in that, The method for preparing the arrayed deformable liquid crystal elastomer terahertz modulated metasurface according to any one of claims 1 to 8 includes: Forming a liquid crystal elastomer substrate; A metal thin film is deposited on one side of the liquid crystal elastomer substrate; The metal thin film is processed into a metasurface structure using photolithography, the metasurface structure comprising multiple open resonant rings arranged in an array; Laser processing is used to create a hollow area around each terahertz modulation unit.

Images