阅读说明：本技术 一种基于石墨烯的极化依赖性可调的太赫兹波吸波器 (Terahertz wave absorber with adjustable polarization dependence based on graphene ) 是由 冉佳 彭东亮 李森茂 李阳 张思文 于 2020-11-24 设计创作，主要内容包括：本发明公开了一种基于石墨烯的极化依赖性可调的太赫兹波吸波器,涉及太赫兹吸波器技术领域,由顶部至底部依次设置的金属结构单元层、介质层和金属层,所述三层结构紧密贴合,所述介质层铺设于所述金属层上表面,所述金属结构单元层铺设于所述介质层上表面,所述介质层还铺设有线状石墨烯,所述金属结构单元层包括四种规格相同的H型金属板,所述金属反射板材料为金,所述介质层材料为聚酰亚胺,通过金属结构单元层以及线状石墨烯谐振单元的整体结构尺寸设计,太赫兹超表面上加载单层石墨烯,通过调节石墨烯的化学势来控制超表面对TE和TM波的吸收率,使太赫兹吸波器获得在太赫兹波段对TE波的良好吸收率,同时对TM波的吸收率实现电压调控。(The invention discloses a terahertz wave absorber with adjustable polarization dependence based on graphene, which relates to the technical field of terahertz wave absorbers, and comprises a metal structure unit layer, a dielectric layer and a metal layer which are sequentially arranged from top to bottom, wherein three layers of structures are tightly attached, the dielectric layer is laid on the upper surface of the metal layer, the metal structure unit layer is laid on the upper surface of the dielectric layer, the dielectric layer is also laid with linear graphene, the metal structure unit layer comprises four H-shaped metal plates with the same specification, the metal reflecting plate material is gold, the dielectric layer material is polyimide, the single-layer graphene is loaded on a terahertz super surface through the overall structural dimension design of the metal structure unit layer and a linear graphene resonance unit, the absorption rate of the super surface to TE and TM waves is controlled by adjusting the chemical potential of the graphene, so that the terahertz wave absorber obtains good absorption rate to the TE waves in a terahertz wave band, and meanwhile, voltage regulation and control are realized on the absorption rate of TM waves.)

1. The terahertz wave absorber based on graphene and having adjustable polarization dependence is characterized by comprising a metal structure unit layer, a dielectric layer (6) and a metal layer (7), wherein the metal structure unit layer, the dielectric layer (6) and the metal layer (7) are sequentially arranged from top to bottom, and the dielectric layer (6) is laid on the metal layer (7); the metal structure unit layer is laid on the dielectric layer (6), the metal structure unit layer comprises four H-shaped metal plates with the same specification, the four H-shaped metal plates are respectively a first H-shaped metal plate (1), a second H-shaped metal plate (2), a third H-shaped metal plate (3) and a fourth H-shaped metal plate (5), the first H-shaped metal plate (1) and the fourth H-shaped metal plate (5) are arranged in an up-down symmetrical mode, the second H-shaped metal plate (2) and the third H-shaped metal plate (3) are arranged in a left-right symmetrical mode, and the first H-shaped metal plate (1) and the fourth H-shaped metal plate (5) are perpendicular to the laying direction of the second H-shaped metal plate and the third H-shaped metal plate (3); linear graphene (4) is further laid on the medium layer (6), one end of the linear graphene (4) is connected with the second H-shaped metal plate (2), and the other end of the linear graphene (4) is connected with the third H-shaped metal plate (3).

2. The graphene-based terahertz wave absorber with adjustable polarization dependence according to claim 1, wherein the metal layer (7) and the H-shaped metal plate are made of gold (7).

3. The graphene-based terahertz wave absorber with adjustable polarization dependence according to claim 1, wherein the dielectric layer (6) is a dielectric layer (6) made of polyimide.

4. The graphene-based terahertz wave absorber with adjustable polarization dependence according to claim 3, wherein the dielectric layer (6) is 8um thick, 202um long and 146.6um wide.

5. The graphene-based terahertz wave absorber with adjustable polarization dependence according to claim 1, wherein the distance between the first H-shaped metal plate (1) and the fourth H-shaped metal plate (5) is 40 um.

6. The graphene-based terahertz wave absorber with adjustable polarization dependence according to claim 1, wherein the distance between the second H-shaped metal plate (2) and the third H-shaped metal plate (3) is 12.3 um.

7. The graphene-based terahertz wave absorber with adjustable polarization dependence according to claim 1, wherein the thickness of the metal layer (7) and the H-shaped metal plate is 0.2 um.

8. The graphene-based terahertz wave absorber with adjustable polarization dependence according to claim 1, wherein the H-shaped metal plate comprises two parallel members and a connecting piece, the connecting piece is located between the two parallel members, and the connecting piece fixes the two parallel members.

9. The graphene-based terahertz wave absorber with adjustable polarization dependence according to claim 8, wherein the length of the connecting piece is 22um, and the width of the connecting piece is 4 um.

10. The graphene-based terahertz wave absorber with adjustable polarization dependence according to claim 1, wherein the linear graphene (4) has a linear line width of 2 um.

Technical Field

The invention relates to the technical field of terahertz wave absorbers, in particular to a graphene-based terahertz wave absorber with adjustable polarization dependence.

Background

The terahertz wave absorber can effectively identify different polarized waves, and has potential application in the fields of high-resolution imaging and safe communication. Therefore, the terahertz wave absorber is very important in information processing. Tunable polarization dependence has been lacking in the terahertz absorber aspect. Tunable polarization dependence means that the up-absorption of the device for waves of different polarization can be adjusted as required.

Conventional wave absorbers are generally constructed from a single localized resonant cell structure. The advantages of a single local resonance unit structure are many, but once the unit structure is determined, the polarization absorption selectivity is fixed, and the adjustment of different polarization selections is difficult. Because a single local resonance cell is difficult to make polarization selection by other means. The polarization-dependent adjustability of the wave-sucker is therefore highly desirable for some sensing and detection applications.

Disclosure of Invention

The inventor finds that the absorption rate of the device in different polarization directions can be adjusted according to requirements by utilizing the periodic resonance unit formed by the metal layer, the dielectric layer, the H-shaped metal structure unit layer and the graphene thin line.

In view of this, the present invention aims to provide a graphene-based terahertz wave absorber with adjustable polarization dependence, which is miniaturized, simple in process, tunable, and polarization-selective.

The invention is realized by the following technical scheme:

a terahertz wave absorber with adjustable polarization dependence based on graphene comprises a metal structure unit layer, a dielectric layer and a metal layer which are sequentially arranged from top to bottom, wherein the three layers are closely attached, and the dielectric layer is laid on the upper surface of the metal layer; the metal structure unit layer is laid on the upper surface of the dielectric layer and comprises four H-shaped metal plates with the same specification, the four H-shaped metal plates are respectively a first H-shaped metal plate, a second H-shaped metal plate, a third H-shaped metal plate and a fourth H-shaped metal plate, the first H-shaped metal plate and the fourth H-shaped metal plate are arranged in an up-down symmetrical mode, the second H-shaped metal plate and the third H-shaped metal plate are arranged in a left-right symmetrical mode, and the first H-shaped metal plate and the fourth H-shaped metal plate are perpendicular to the laying direction of the second H-shaped metal plate and the third H-shaped metal plate; the medium layer is further paved with linear graphene, one end of the linear graphene is connected with the second H-shaped metal plate, and the other end of the linear graphene is connected with the third H-shaped metal plate.

In this scheme, the linear graphene is as graphite alkene resonance unit, and to the holistic structural design of four kinds of H type metal sheets that the specification is the same of metallic structure unit layer, through changing external voltage, can adjust the chemical potential of linear graphene to the super surface of control is to the absorptivity of TE and TM wave, makes terahertz wave absorber obtain at terahertz wave band to the good absorptivity of TE wave, realizes realizing voltage regulation and control to the absorptivity of TM wave simultaneously.

Further, the metal layer and the H-shaped metal plate are made of gold.

In the scheme, the hardware has higher conductivity, high-temperature resistance and chemical corrosion resistance, gold is selected as the metal layer at the bottommost layer, so that the metal layer can provide stable high reflectivity for a long time, and meanwhile, the metal is selected as the material of the H-shaped metal plate, so that the ohmic loss during resonance can be improved, and the wave absorption efficiency of the wave absorber is comprehensively improved by combining the high reflectivity of the metal layer at the bottom layer.

Preferably, the dielectric layer is made of polyimide.

In the scheme, the dielectric layer made of polyimide has low electrical constant and strong flexibility, and can be used as an ultrathin substrate.

Further, the dielectric layer is 8um thick, 202um long, 146.6um wide.

Preferably, the distance between the first H-shaped metal plate and the fourth H-shaped metal plate is 40 um.

Preferably, the distance between the second H-shaped metal plate and the third H-shaped metal plate is 12.3 um.

Preferably, the metal layer with H type metal sheet thickness is 0.2um, satisfies the preparation technology, avoids influencing the resonant frequency of TE TM polarized wave, and then control the absorptivity.

Further, the H-shaped metal plate comprises two parallel members and a connecting piece, wherein the connecting piece is positioned between the two parallel members, and the connecting piece is used for fixing the two parallel members.

Preferably, the connector length is 22um, the connector width is 4 um.

Preferably, the linear graphene line width is 2 um.

Compared with the prior art, the invention has the following advantages and beneficial effects:

1. the graphene-based terahertz wave absorber with adjustable polarization dependence adopts two pairs of symmetrical H-shaped metal structures, so that the absorption rate in the TE and TM directions can be improved.

2. The graphene-based terahertz wave absorber with adjustable polarization dependence can adjust the absorption rate in the TM direction by adopting the linear graphene.

3. The graphene-based terahertz wave absorber with adjustable polarization dependence can realize the polarization dependence characteristic of a voltage-regulated absorber conveniently and quickly, and is expected to be applied to the fields of high resolution, imaging, safe communication and the like.

4. The graphene-based terahertz wave absorber with adjustable polarization dependence is simple in structure and convenient to prepare and use.

Drawings

The accompanying drawings, which are included to provide a further understanding of the embodiments of the invention and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the invention and together with the description serve to explain the principles of the invention. In the drawings:

FIG. 1 is a top view of an embodiment of the present invention;

FIG. 2 is a side view of an embodiment of the present invention;

FIG. 3 is a front view of an embodiment of the present invention;

FIG. 4 is a schematic view of the overall structure in an embodiment of the present invention;

FIG. 5 is a graph of absorption in the TM and TE directions versus frequency for graphene at a chemical potential of 0eV in an embodiment of the present invention;

FIG. 6 is a graph of absorption in the TM and TE directions versus frequency for graphene at a chemical potential of 0.8eV in an embodiment of the present invention;

fig. 7 is a graph showing the relationship between the absolute value of the change in the TE and TM wave absorptance and the frequency when graphene is at the chemical potentials of 0eV and 0.8eV in the embodiment of the present invention.

Reference numbers and corresponding part names:

1. a first H-shaped metal plate; 2. a second H-shaped metal plate; 3. a third H-shaped metal plate; 4. linear graphene; 5. a fourth H-shaped metal plate; 6. a dielectric layer; 7. a metal layer.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail below with reference to examples and accompanying drawings, and the exemplary embodiments and descriptions thereof are only used for explaining the present invention and are not meant to limit the present invention.

In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. However, it will be apparent to one of ordinary skill in the art that: it is not necessary to employ these specific details to practice the present invention. In other instances, well-known structures, circuits, materials, or methods have not been described in detail so as not to obscure the present invention.

Throughout the specification, reference to "one embodiment," "an embodiment," "one example," or "an example" means: the particular features, structures, or characteristics described in connection with the embodiment or example are included in at least one embodiment of the invention. Thus, the appearances of the phrases "one embodiment," "an embodiment," "one example" or "an example" in various places throughout this specification are not necessarily all referring to the same embodiment or example. Furthermore, the particular features, structures, or characteristics may be combined in any suitable combination and/or sub-combination in one or more embodiments or examples. Further, those of ordinary skill in the art will appreciate that the illustrations provided herein are for illustrative purposes and are not necessarily drawn to scale. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

In the description of the present invention, it is to be understood that the terms "front", "rear", "left", "right", "upper", "lower", "vertical", "horizontal", "high", "low", "inner", "outer", etc. indicate orientations or positional relationships based on those shown in the drawings, and are only for convenience of description and simplicity of description, and do not indicate or imply that the referenced devices or elements must have a particular orientation, be constructed and operated in a particular orientation, and therefore, are not to be construed as limiting the scope of the present invention.

Examples

The invention relates to a terahertz wave absorber with adjustable polarization dependence based on graphene, which has a structure shown in figures 1, 2, 3 and 4, and comprises a plurality of wave absorbing unit layers, specifically a metal structure unit layer, a dielectric layer 6 and a metal bottom plate which are sequentially arranged from top to bottom, wherein the dielectric layer is a substrate, the three layers of structures are tightly attached to each other, and the substrate is laid on the upper surface of the metal bottom plate; the metal structure unit layer is laid on the upper surface of the substrate and comprises four H-shaped metal plates with the same specification, the four H-shaped metal plates are respectively a first H-shaped metal plate 1, a second H-shaped metal plate 2, a third H-shaped metal plate 3 and a fourth H-shaped metal plate 5, the first H-shaped metal plate 1 and the fourth H-shaped metal plate 5 are vertically symmetrical, the second H-shaped metal plate 2 and the third H-shaped metal plate 3 are bilaterally symmetrical, and the first H-shaped metal plate 1 and the fourth H-shaped metal plate 5 are perpendicular to the laying direction of the second H-shaped metal plate 2 and the third H-shaped metal plate 3; linear graphene 4 is further paved on the upper surface of the substrate, one end of the linear graphene 4 is connected with the second H-shaped metal plate 2, and the other end of the linear graphene 4 is connected with the third H-shaped metal plate 3.

Preferably, in the above embodiment, the metal layer 7 and the H-shaped metal plate are made of gold, so as to comprehensively improve the wave absorbing efficiency of the wave absorber.

As a preference of the above embodiment, the dielectric layer 6 is a dielectric layer 6 made of polyimide.

Further, the H-shaped metal plate comprises two parallel members and a connecting piece, the connecting piece is located between the two parallel members, the connecting piece fixes the two parallel members, and specifically, the two ends of the connecting piece are respectively fixed at the middle points of the two parallel members.

It should be noted that, a specific connection relationship is that two parallel members corresponding to the third H-shaped metal plate 3 and the second H-shaped metal plate 2 located on the left and right sides are connected to the linear graphene 4, a connection position is that a midpoint of the two parallel members is fixed to two ends of the linear graphene 4, and two connection members corresponding to the third H-shaped metal plate 3 and the second H-shaped metal plate 2 are located on the same straight line in the horizontal direction as the linear graphene 4. The midpoint of the parallel members of the first H-shaped metal plate 1 and the fourth H-shaped metal plate 5 and the midpoint of the linear graphene 4 are located on the same vertical straight line, and the midpoint of the linear graphene 4 is located at the midpoint of the substrate.

Based on above-mentioned device, through utilizing applied voltage, change the chemical potential of graphite alkene to change the conductivity of graphite alkene, and then change response current distribution on the super surface, control resonant frequency changes the absorption rate of different frequencies. When the chemical potential of the graphene is adjusted to be 0eV, terahertz waves are incident from the left side of the structure shown in fig. 2 and are reflected by the reflective metal plate. As can be seen from fig. 5, for both TE wave and TM wave of 1.715THz, the first H-shaped metal plate 1, the second H-shaped metal plate 2, the third H-shaped metal plate 3, and the fourth H-shaped metal plate 5 can be excited to resonate, resulting in loss, and thus good absorption rate is obtained. When the chemical potential of graphene is adjusted to be 0.8eV, the second and third H-shaped metal plates 2 and 3 are connected by graphene, and as shown in fig. 6, the resonant frequency changes, and no resonance occurs at 1.715Hz, so that the TM wave absorption rate at that frequency decreases.

It can be understood that the thickness of the metal layer and the H-shaped metal plate is 0.2um, so that the preparation process is satisfied, the influence on the resonant frequency of TE/TM polarized waves is avoided, and the absorption rate is further controlled.

As a preferred example of the above embodiment, as shown in fig. 4, the graphene-based terahertz wave absorber with adjustable polarization dependence of the present invention has the following structural parameters: the substrate width Px is 146.6um, the substrate length Py is 202um, the substrate thickness is 8um, the distance S1 between the second H-shaped metal plate 2 and the third H-shaped metal plate 3 is 12.3um, the distance S2 between the first H-shaped metal plate 1 and the fourth H-shaped metal plate 5 is 40um, the line width W1 of the linear graphene 4 is 2um, the connector width W2 is 4um, and the connector length L2 is 22 um.

In this example, when the graphene chemical potential is 0eV, as shown in fig. 5, the absorption peaks of TE and TM waves are concentrated at f ═ 1.715THz, and the absorptance is 93.9% and 86.7%, respectively. When the chemical potential of the graphene is increased to 0.8eV, as shown in FIG. 6, the absorption change of the TE wave is small and is maintained at 95%, and the absorption rate of the TM wave is reduced to 42.2% at 1.715 THz.

In addition, in the two chemical potentials of 0eV and 0.8eV, as shown in fig. 7, the absolute value of the change in the absorption rate of TE and TM waves shows that the change in TE waves is 1.1% and the change in TM waves reaches 44.5% for 1.715 THz.

Therefore, the graphene-based terahertz wave absorber with adjustable polarization dependence can realize the polarization dependence characteristic of the voltage-adjusted wave absorber conveniently and conveniently, and is expected to be applied to the fields of high-resolution imaging, safe communication and the like.

The above-mentioned embodiments are intended to illustrate the objects, technical solutions and advantages of the present invention in further detail, and it should be understood that the above-mentioned embodiments are merely exemplary embodiments of the present invention, and are not intended to limit the scope of the present invention, and any modifications, equivalent substitutions, improvements and the like made within the spirit and principle of the present invention should be included in the scope of the present invention.