Metasurface structure with terahertz linear polarization selective permeability

Abstract

The invention provides a metasurface structure with terahertz linear polarization selective permeability, which comprises a plurality of terahertz metasurface units arranged periodically, and is characterized in that each terahertz metasurface unit comprises a top pattern layer, a middle dielectric layer and a substrate material layer which are sequentially arranged from top to bottom; the top pattern layer comprises a circular ring piece with two openings, the two openings are symmetrically arranged relative to the circle center of the circular ring piece, and the substrate material layer comprises a plurality of grid pieces arranged at intervals. According to the metasurface structure with the terahertz linear polarization selective permeability disclosed by the embodiment of the invention, in the transmission channel, by adjusting the position of the top pattern layer and / or the position of the substrate material layer, the incident polarized wave selectively transmitted by the metasurface structure with the terahertz linear polarization selective permeability can be adjusted; and unique broadband terahertz linear polarization selective transmission response is realized. In addition, the metasurface structure with the terahertz linear polarization selective permeability has the advantages of being simple in structure and easy to integrate.

Description

Technical Field

[0001] The embodiments of the present disclosure belong to the technical field of terahertz multifunctional devices, and specifically relate to a metasurface structure with terahertz linear polarization selective transmittance. Background Art

[0002] Electromagnetic metamaterials (metamaterials), also known as artificial electromagnetic media or metamaterials, are a class of artificial composite materials composed of periodic or aperiodic arrangements of subwavelength unit cells. By precisely controlling the geometric parameters and spatial arrangement of their microstructures, these materials can exhibit unique electromagnetic response properties not found in traditional natural materials, such as negative refractive index, double negative properties (negative permittivity and negative permeability), and programmable gradient distributions of electromagnetic parameters. These properties not only expand the boundaries of classical electromagnetic theory but also provide new physical mechanisms and design freedom for electromagnetic wave manipulation. However, traditional three-dimensional electromagnetic metamaterials still face numerous challenges in practical applications, including complex structures, bulky size, high losses, and difficulty in integration, which significantly limit their widespread application in engineering. To address these issues, researchers have proposed artificial electromagnetic metasurfaces (metasurfaces), the two-dimensional equivalent of three-dimensional metamaterials. Metasurfaces are composed of subwavelength-scale artificial units arranged in a specific pattern on a flat or curved surface. Their thickness is much smaller than the operating wavelength, resulting in the advantages of being ultra-thin, lightweight, and having low losses. Compared to three-dimensional metamaterials, metasurfaces offer significant improvements in manufacturing processes, system integration, and design flexibility. They can also achieve similar electromagnetic control functions, such as wavefront shaping, polarization conversion, and anomalous refraction. Thanks to these properties, metasurfaces have become an important technological enabler in cutting-edge fields such as terahertz wave manipulation, optical stealth, and super-resolution imaging, providing new technical paths and application prospects for the development of next-generation electromagnetic devices.

[0003] Terahertz (THz) waves, located in the electromagnetic spectrum between microwaves and infrared, possess unique physical properties such as low photon energy, strong penetration, and wide spectral bandwidth. These properties hold significant potential for applications in high-speed wireless communications, non-destructive biomedical testing, high-precision security imaging, and material spectral analysis. However, practical applications such as THz communication systems, high-resolution imaging equipment, and precision sensing and detection technologies often require precise control of the amplitude, phase, and polarization state of THz waves. Traditional optical materials, constrained by their intrinsic properties and structural size, have limited control capabilities in the THz band, making them inadequate for modern applications. In recent years, THz control devices based on artificial electromagnetic metasurfaces have become a key research area for THz functional devices due to their flexible structural design, compact size, and ease of system integration. Metasurfaces, through carefully designed subwavelength structural units, enable flexible manipulation of THz wavefronts, polarization states, and amplitude. However, most current metasurface devices offer limited functionality, enabling specific beam steering or polarization conversion, which falls short of application requirements. Therefore, there is an urgent need to develop a terahertz metasurface structure to solve the above problems. Summary of the Invention

[0004] The embodiments of the present disclosure aim to solve at least one of the technical problems existing in the prior art and provide a metasurface structure with terahertz linear polarization selective transmittance.

[0005] The present disclosure provides a metasurface structure with terahertz linear polarization selective transmission, comprising a plurality of periodically arranged terahertz metasurface units, wherein the terahertz metasurface units comprise a top pattern layer, an intermediate dielectric layer, and a base material layer sequentially arranged from top to bottom; The top pattern layer includes a circular ring member having two openings, wherein the two openings are symmetrically arranged about the center of the circular ring member; The base material layer includes a plurality of grid members that are spaced apart and arranged in parallel.

[0006] In some embodiments of the present disclosure, the top pattern layer is made of gold, the thickness of the top pattern layer is 0.3 μm, the outer ring radius of the circular ring is 9 μm, and the inner ring radius of the circular ring is 7 μm.

[0007] In some embodiments of the present disclosure, the width of the opening is 2 μm.

[0008] In some embodiments of the present disclosure, a cross section of the intermediate dielectric layer perpendicular to the thickness direction of the intermediate dielectric layer is square, and a period of the intermediate dielectric layer is 20 μm.

[0009] In some embodiments of the present disclosure, the intermediate dielectric layer is made of polyimide, has a thickness of 8.5 μm, a dielectric constant of 3.5, and a dielectric loss angle of 0.0027.

[0010] In some embodiments of the present disclosure, a plurality of the grid members are arranged in parallel and evenly.

[0011] In some embodiments of the present disclosure, an extending direction of the grid member is the same as a direction of the opening of the circular ring member.

[0012] In some embodiments of the present disclosure, an extension direction of the grid member is perpendicular to a direction of the opening of the circular ring member.

[0013] In some embodiments of the present disclosure, the grid member includes a longitudinal bar and two transverse bars, and the two transverse bars are respectively arranged at opposite ends of the longitudinal bar.

[0014] In some embodiments of the present disclosure, the spacing between the two closest transverse strips of two adjacent grid pieces is 0.5 μm, the length of the longitudinal strip along the extension direction of the grid piece is 15 μm, the length of the transverse strip is 1.5 μm, and the width of the longitudinal strip along the extension direction perpendicular to the grid piece is 1.5 μm.

[0015] In some embodiments of the present disclosure, the base material layer is made of gold, the thickness of the base material layer is 0.3 μm, and the electrical conductivity of the base material layer is 4.561×10 7 S / m. The metasurface structure with terahertz linear polarization selective transmittance of the embodiment of the present disclosure includes a plurality of periodically arranged terahertz metasurface units, wherein the terahertz metasurface unit includes a top pattern layer, an intermediate dielectric layer and a base material layer arranged in sequence from top to bottom, wherein the top pattern layer includes a circular ring member, the circular ring member has two openings, and the two openings are symmetrically arranged about the center of the circular ring member, and the base material layer includes a plurality of spaced grid members. The metasurface structure with terahertz linear polarization selective transmittance of the embodiment of the present disclosure, in the transmission channel, can adjust the incident polarized wave selectively transmitted by the metasurface structure with terahertz linear polarization selective transmittance by adjusting the position of the top pattern layer and / or the position of the base material layer, thereby achieving a unique broadband terahertz linear polarization selective transmission response. In addition, the metasurface structure with terahertz linear polarization selective transmittance of the embodiment of the present disclosure also has the characteristics of simple structure and easy integration. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 Schematic diagram of the overall structure of a metasurface structure with terahertz linear polarization selective transmittance according to an embodiment of the present disclosure; Figure 2 for Figure 1 A top view of the metasurface structure with terahertz linear polarization selective transmission; Figure 3 for Figure 1 A schematic structural diagram of the base material layer shown; Figure 4 for Figure 1 A schematic diagram of a first embodiment of a metasurface structure with terahertz linear polarization selective transmittance is shown; Figure 5 for Figure 1 A schematic diagram of a second embodiment of a metasurface structure with terahertz linear polarization selective transmittance is shown; Figure 6 for Figure 1 A schematic diagram of a third embodiment of a metasurface structure with terahertz linear polarization selective transmission is shown; Figure 7 for Figure 4 A transmission coefficient curve diagram of the metasurface structure with terahertz linear polarization selective transmittance under different linear polarization wave incidences of the first embodiment is shown; Figure 8 for Figure 5 A transmission coefficient curve diagram of the metasurface structure with terahertz linear polarization selective transmittance under different linear polarization wave incidences according to the second embodiment is shown; Figure 9 for Figure 6 The transmission coefficient curves of the metasurface structure with terahertz linear polarization selective transmittance under different linear polarization wave incidences of the third embodiment are shown.

[0017] The reference numerals in the accompanying drawings represent the following: 100. Terahertz metasurface unit; 10. Top pattern layer; 11. Circular ring; 111. Arc strip; 112. Opening; 20. Intermediate dielectric layer; 30. Base material layer; 31. Grid member; 311. Longitudinal strips; 312. Transverse strips; h1, thickness of the base material layer; h2, thickness of the intermediate dielectric layer; h3, thickness of the top pattern layer; r1, outer ring radius of the circular ring; r2, inner ring radius of the circular ring; g1, opening width of the circular ring; g2, length of the transverse strip along the extension direction of the grid piece; g3, length of the longitudinal strip; g4, spacing between two adjacent grid pieces; g5, width of the transverse strip; P, period of the terahertz metasurface unit. DETAILED DESCRIPTION

[0018] Exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments described herein. Rather, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art.

[0019] It should be understood that the terms used herein are for the purpose of describing specific example embodiments only and are not intended to be limiting. Unless the context clearly indicates otherwise, the singular forms "one", "an" and "said" as used herein may also be meant to include plural forms. The terms "comprise", "include", "contain" and "have" are inclusive and therefore specify the presence of stated features, steps, operations, elements and / or parts, but do not exclude the presence or addition of one or more other features, steps, operations, elements, parts, and / or combinations thereof. The method steps, processes, and operations described herein are not to be construed as necessarily requiring them to be performed in the specific order described or illustrated, unless the order of execution is clearly indicated. It should also be understood that additional or alternative steps may be used.

[0020] Although the terms first, second, third, etc. can be used in the text to describe multiple elements, components, regions, layers and / or sections, these elements, components, regions, layers and / or sections should not be limited by these terms. These terms can only be used to distinguish an element, component, region, layer or section from another region, layer or section. Unless the context clearly indicates otherwise, terms such as "first", "second" and other numerical terms do not imply order or sequence when used in the text. Therefore, the first element, component, region, layer or section discussed below can be referred to as the second element, component, region, layer or section without departing from the teaching of the example embodiments.

[0021] For ease of description, spatially relative terms may be used herein to describe the relationship of one element or feature relative to another element or feature as shown in the figures, such as "inside," "outside," "inside," "outside," "below," "beneath," "above," and the like. Such spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is flipped, an element described as "below" or "beneath" another element or feature would then be oriented as "above" or "above" the other element or feature. Thus, the example term "below" can encompass both above and below orientations. The device may be otherwise oriented (rotated 90 degrees or in other orientations) and the spatially relative descriptors used herein are interpreted accordingly.

[0022] like Figures 1 to 3 As shown, the present disclosure provides a metasurface structure with terahertz linear polarization selective transmittance, including a plurality of periodically arranged terahertz metasurface units 100, wherein the terahertz metasurface unit 100 includes a top pattern layer 10, an intermediate dielectric layer 20 and a base material layer 30 arranged in sequence from top to bottom; the top pattern layer 10 includes a circular ring member 11 with two openings 112, and the two openings 112 are symmetrically arranged about the center of the circular ring member 11, and the base material layer 30 includes a plurality of grid members 31 spaced apart and arranged in parallel.

[0023] The metasurface structure with terahertz linear polarization selective transmittance of the embodiment of the present disclosure includes a plurality of periodically arranged terahertz metasurface units 100, wherein the terahertz metasurface unit 100 includes a top pattern layer 10, an intermediate dielectric layer 20 and a base material layer 30 arranged in sequence from top to bottom, wherein the top pattern layer 10 includes a circular ring member 11, the circular ring member 11 has two openings 112, and the two openings 112 are symmetrically arranged about the center of the circular ring member 11, and the base material layer 30 includes a plurality of spaced grid members 31. The metasurface structure with terahertz linear polarization selective transmittance of the embodiment of the present disclosure, in the transmission channel, can adjust the incident polarized wave selectively transmitted by the metasurface structure with terahertz linear polarization selective transmittance by adjusting the position of the top pattern layer 10 and / or the position of the base material layer 30, thereby achieving a unique broadband terahertz linear polarization selective transmittance response. In addition, the metasurface structure with terahertz linear polarization selective transmittance of the embodiment of the present disclosure also has the characteristics of simple structure and easy integration.

[0024] like Figure 1 、 Figure 2As shown, the circular ring 11 includes two identical curved strips 111, which are symmetrically arranged about the center of the circular ring 11. That is, the two curved strips 111 are concave toward each other. Two openings 112, symmetrical about the center of the circular ring 11, separate the circular ring 11 into the two curved strips 111. Along a radial direction perpendicular to the circular ring 11, the distance between the two curved strips 111 is the width of the opening 112. Specifically, the width g1 of the opening 112 is 2 μm.

[0025] In some embodiments of the present disclosure, the outer radius r2 of the circular ring 11 is 9 μm, and the inner radius r1 of the circular ring 11 is 7 μm. That is, the outer radius r2 of the arc strip 111 is 9 μm, and the inner radius r1 of the arc strip 111 is 7 μm.

[0026] In some embodiments of the present disclosure, the top pattern layer 10 is made of gold. This gold-based top pattern layer 10 can enhance the controllability of the metasurface structure with terahertz linear polarization selective transmittance. The top pattern layer 10 is fabricated using laser direct write etching or other photolithography techniques. Specifically, the thickness h3 of the top pattern layer 10 is 0.3 μm.

[0027] In some embodiments of the present disclosure, the intermediate dielectric layer 20 is made of polyimide, the dielectric constant of the intermediate dielectric layer 20 is 3.5, and the dielectric loss factor of the intermediate dielectric layer 20 is 0.0027.

[0028] In some embodiments of the present disclosure, the thickness h2 of the intermediate dielectric layer 20 is 8.5 μm. Perpendicular to the thickness direction of the intermediate dielectric layer 20, the cross-section of the intermediate dielectric layer 20 is a square with a side length of 20 μm. The side length of the intermediate dielectric layer 20 is the period of the intermediate dielectric layer 20. The period of the intermediate dielectric layer 20 is the period P of the terahertz metasurface unit. Specifically, the period P is 20 μm.

[0029] like Figure 1 、 Figure 3 As shown, in some embodiments of the present disclosure, the base material layer 30 includes a plurality of grid members 31, and the plurality of grid members 31 are spaced and evenly arranged. Specifically, the plurality of grid members 31 are arranged in parallel and perpendicular to the extension direction of the grid members 31, and the plurality of grid members 31 are spaced and evenly arranged.

[0030] In some embodiments of the present disclosure, Figure 1 、 Figure 4 、 Figure 6 As shown, the extending direction of the grid member 31 is the same as the direction of the opening 112 of the circular ring member 11. Specifically, the direction from one opening 112 of the circular ring member 11 to the other opening 112 of the circular ring member 11 is the same as the extending direction of the grid member 31. Figure 6 and Figure 4 The difference is that Figure 6 The extension direction of the grid member 31 of the metasurface structure of the third embodiment is Figure 4 The extension direction of the grid members 31 of the metasurface structure of the first embodiment is vertical. Specifically, Figure 6 The extending direction of the grid member 31 is from left to right.

[0031] In some other embodiments of the present disclosure, Figure 5 As shown, the extending direction of the grid member 31 is perpendicular to the direction of the opening 112 of the circular ring member 11. Specifically, the direction from one opening 112 of the circular ring member 11 to the other opening 112 of the circular ring member 11 is perpendicular to the extending direction of the grid member 31. Figure 5 The extending direction of the grid member 31 in the second embodiment shown is the same as Figure 6 The extension direction of the grid elements 31 in the third embodiment shown is vertical.

[0032] In some embodiments of the present disclosure, the grid member 31 includes a longitudinal bar 311 and two transverse bars 312, and the two transverse bars 312 are respectively provided at opposite ends of the longitudinal bar 311. Specifically, the longitudinal bar 311 extends in the same direction as the grid member 31, that is, along the extension direction of the grid member 31, and the two longitudinal bars 311 are provided at opposite ends of the longitudinal bar 311.

[0033] In some embodiments of the present disclosure, the cross-sections of the longitudinal strips 311 and the transverse strips 312 are both rectangular, perpendicular to the thickness of the base material layer 30. Specifically, along the extension direction of the grid member 31, the length g3 of the longitudinal strips 311 is 15 μm, and the length g2 of the transverse strips 312 is 1.5 μm. The width g5 of the longitudinal strips 311, perpendicular to the extension direction of the grid member 31, is 1.5 μm.

[0034] The distance between the two closest transverse strips 312 of two adjacent grid members 31 is 0.5 μm, that is, perpendicular to the extension direction of the grid members 31, the distance between the two adjacent transverse strips 312 is 0.5 μm, that is, the distance g4 between two adjacent grid members 31 is 0.5 μm.

[0035] In some embodiments of the present disclosure, the thickness h1 of the base material layer 30 is 0.3 μm, that is, the thickness of the grid members 31 is 0.3 μm. Specifically, the base material layer 30 is formed by preparing a plurality of spaced and evenly distributed grid members 31 by reactive ion etching.

[0036] Specifically, the base material layer 30 is made of gold, and the electrical conductivity of the base material layer 30 is 4.561×10 7 S / m. The performance of the metasurface structure with terahertz linear polarization selective transmittance in the embodiments of the present disclosure is reflected by parameters such as the transmission coefficient.

[0037] When x-polarized incident light is incident, the transmittance formula of the metasurface structure with terahertz linear polarization selective transmittance is: ; Among them, T x is the transmittance at x-polarized incidence, T yx is the cross-polarization transmission coefficient when x-polarized incident, T xx is the co-polarization transmission coefficient for x-polarized incidence.

[0038] When y-polarization is incident, the transmittance formula of the metasurface structure with terahertz linear polarization selective transmittance is: ; Among them, T y is the transmittance at y-polarized incidence, T xy is the cross-polarization transmission coefficient when the incident light is y-polarized, T yy is the co-polarization transmission coefficient for y-polarized incidence. like Figures 7 to 9 As shown, the transmittance, transmission coefficient, etc. of the first to third embodiments are simulated and calculated using SCT simulation software to obtain a curve graph corresponding to each embodiment.

[0039] Figure 7 Shown as Figure 4 The transmission coefficient curve of the metasurface structure with terahertz linear polarization selective transmission under different linear polarization wave incidence of the first embodiment is shown, wherein the horizontal axis is the frequency (THz) and the vertical axis is the transmission coefficient. Figure 7 It can be seen that when different linear polarization waves are incident on the metasurface structure with terahertz linear polarization selective transmittance, the transmission response of the metasurface structure with terahertz linear polarization selective transmittance is different. Specifically, when the frequency is in the range of 4~6THz, T xx More than 0.8, T yy 、T xy、 T yz The values of are almost close to 0. It can be seen that this structure can selectively transmit x-polarized waves.

[0040] Figure 8 Shown as Figure 5 The transmission coefficient curve of the metasurface structure with terahertz linear polarization selective transmission under different linear polarization wave incidence of the second embodiment shown, wherein the horizontal axis is the frequency (THz) and the vertical axis is the transmission coefficient. Figure 8It can be seen that when different linear polarization waves are incident on the metasurface structure with terahertz linear polarization selective transmittance, the transmission response of the metasurface structure with terahertz linear polarization selective transmittance is different. Specifically, when the frequency is in the range of 4.5~5.6THz, T xx 、T yy 、T xy、 T yz The values of are all less than 0.2. It can be seen that this structure is not transparent to both x-polarized waves and y-polarized waves.

[0041] Figure 9 Shown as Figure 6 The transmission coefficient curve of the metasurface structure with terahertz linear polarization selective transmission under different linear polarization wave incidence of the third embodiment is shown, wherein the horizontal axis is the frequency (THz) and the vertical axis is the transmission coefficient. Figure 9 It can be seen that when different linear polarization waves are incident on the metasurface structure with terahertz linear polarization selective transmittance, the transmission response of the metasurface structure with terahertz linear polarization selective transmittance is different. Specifically, when the frequency is in the range of 4~6THz, T yy More than 0.8, T xx 、T xy、 T yz The values of are almost close to 0. It can be seen that this structure can selectively transmit y-polarized waves.

[0042] When the relative positions of the top pattern layer 10 or the base material layer 30 are changed, the metasurface structure exhibits different transmission responses when different linearly polarized waves are incident on the metasurface structure. In the transmission channel, different linearly polarized waves can be selected to pass through according to different structural position states. This precise control mechanism for the amplitude of electromagnetic waves can be applied to fields such as resolution enhancement of near-field imaging systems and multi-channel information encryption transmission. In addition, this amplitude control capability can also work synergistically with multiple physical parameters such as polarization and frequency, and be applied to new multifunctional integrated photonic devices, terahertz communications, high-resolution imaging, and precision sensing.

[0043] It is understood that the above embodiments are merely exemplary embodiments for illustrating the principles of the present disclosure, and the present disclosure is not limited thereto. Those skilled in the art may make various modifications and improvements without departing from the spirit and substance of the present disclosure, and such modifications and improvements are also considered to be within the scope of protection of the present disclosure.

Claims

1. A metasurface structure with terahertz linear polarization selective permeability, characterized in that: The terahertz metasurface comprises a plurality of periodically arranged terahertz metasurface units, wherein the terahertz metasurface unit comprises a top pattern layer, an intermediate dielectric layer and a base material layer arranged in sequence from top to bottom; The top pattern layer includes a circular ring member having two openings, wherein the two openings are symmetrically arranged about the center of the circular ring member; The base material layer includes a plurality of grid members that are spaced apart and arranged in parallel.

2. The metasurface structure with terahertz linear polarization selective transmission according to claim 1, characterized in that: The material of the top pattern layer is gold, the thickness of the top pattern layer is 0.3 μm, the outer ring radius of the circular ring is 9 μm, and the inner ring radius of the circular ring is 7 μm.

3. The metasurface structure with terahertz linear polarization selective transmission according to claim 1, characterized in that: The width of the opening is 2 μm.

4. The metasurface structure with terahertz linear polarization selective transmission according to claim 1, wherein: The cross section of the intermediate dielectric layer perpendicular to the thickness direction of the intermediate dielectric layer is square, and the period of the intermediate dielectric layer is 20 μm.

5. The metasurface structure with terahertz linear polarization selective transmission according to claim 1, wherein: The material of the intermediate dielectric layer is polyimide, the thickness of the intermediate dielectric layer is 8.5 μm, the dielectric constant of the intermediate dielectric layer is 3.5, and the dielectric loss angle of the intermediate dielectric layer is 0.0027.

6. The metasurface structure with terahertz linear polarization selective transmission according to claim 1, wherein: The extending direction of the grid member is the same as the direction of the opening of the circular ring member.

7. The metasurface structure with terahertz linear polarization selective transmission according to claim 1, characterized in that: An extending direction of the grid member is perpendicular to a direction of the opening of the circular ring member.

8. The metasurface structure with terahertz linear polarization selective transmission according to claim 1, wherein: The grid member includes a longitudinal bar and two transverse bars, and the two transverse bars are respectively arranged at opposite ends of the longitudinal bar.

9. The metasurface structure with terahertz linear polarization selective transmission according to claim 8, characterized in that: The distance between the two closest transverse strips of two adjacent grid pieces is 0.5 μm. Along the extension direction of the grid piece, the length of the longitudinal strip is 15 μm, the length of the transverse strip is 1.5 μm, and along the extension direction perpendicular to the grid piece, the width of the longitudinal strip is 1.5 μm.

10. The metasurface structure with terahertz linear polarization selective transmission according to claim 1, wherein: The base material layer is made of gold, the thickness of the base material layer is 0.3 μm, and the electrical conductivity of the base material layer is 4.561×10 7 S / m.

Images