CN108718006B

CN108718006B - Three-band topological metamaterial terahertz wave absorber

Info

Publication number: CN108718006B
Application number: CN201810372928.0A
Authority: CN
Inventors: 王玥; 陈素果
Original assignee: Xian University of Technology
Current assignee: Xian University of Technology
Priority date: 2018-04-24
Filing date: 2018-04-24
Publication date: 2020-08-18
Anticipated expiration: 2038-04-24
Also published as: CN108718006A

Abstract

The invention discloses a three-band topological metamaterial terahertz wave absorber which comprises a plurality of wave absorbing units which are sequentially arranged, wherein each wave absorbing unit is sequentially provided with a metal layer, a dielectric layer and a metal microstructure unit layer from the bottom layer to the top layer, the three layers of structures are tightly attached, the metal microstructure unit layer comprises three parts which are mutually connected on the same plane, and the specific structure is as follows: the optical fiber grating sensor comprises a pair of I-shaped structures which are symmetrically arranged, one of two horizontal edges of each I-shaped structure is shorter than the other one, the short edges of the two I-shaped structures are symmetrical along a horizontal line, the vertical parts of the two I-shaped structures are also covered with a square window structure, the square window structure takes the symmetrical axis of the short edges of the two I-shaped structures as an axisymmetric structure, and a dielectric layer is a polyimide film with the dielectric constant of 2.88 and the loss tangent of 0.0032.

Description

Three-band topological metamaterial terahertz wave absorber

Technical Field

The invention belongs to the technical field of terahertz metamaterials, and particularly relates to a terahertz wave absorber of a three-band topological metamaterial.

Background

The perfect metamaterial wave absorber attracts wide attention because of the ability of absorbing incident waves by almost one hundred percent, and is formed by periodically arranging certain units, and by means of the design of corresponding geometric parameters and geometric structures in the periodic units, electromagnetic waves of a certain frequency band incident on the structure are coupled so as to almost perfectly absorb the incident electromagnetic waves. Near perfect absorber assemblies have potential applications in the fields of spectroscopy, selective emitters, high efficiency solar cells, plasma sensors, and stealth. The metamaterial absorber structure covering the surfaces of the airplane and the warship can effectively avoid the detection and tracking of enemies, and in addition, the metamaterial absorber can also reduce the electromagnetic leakage of electronic devices such as household appliances and mobile phones and reduce the damage of electromagnetic radiation to human bodies. Since the first metamaterial absorbers, many types of single-band absorbers have been proposed in succession. And in the terahertz waveband, the multiband perfect metamaterial absorber is more attractive, and is the main development direction at present. Therefore, there is a need to design a terahertz waveband multi-band wave absorber which can be obviously used in the fields of security, imaging systems, thermal detectors and the like.

Disclosure of Invention

The invention aims to provide a three-band topological metamaterial terahertz wave absorber which has the characteristics of wide incident angle, polarization sensitivity, simple structure, thin thickness and the like and has great application potential in the fields of confidentiality, imaging systems, thermal detectors and the like.

The technical scheme adopted by the invention is that the three-band topological metamaterial terahertz wave absorber comprises a plurality of wave absorbing units which are sequentially arranged, wherein each wave absorbing unit comprises a metal layer, a dielectric layer and a metal microstructure unit layer from the bottom layer to the top layer, the three layers of structures are tightly attached, and three absorption peaks are formed in a terahertz wave band.

The present invention is also characterized in that,

the metal microstructure unit layer comprises three parts which are connected with each other on the same plane, and the specific structure is as follows: the window comprises a pair of I-shaped structures which are symmetrically arranged, one of two horizontal edges of each I-shaped structure is shorter than the other edge, the short edges of the two I-shaped structures are symmetrical along a horizontal line, the vertical parts of the two I-shaped structures are also covered with a square window structure, and the square window structure takes the symmetrical axis of the short edges of the two I-shaped structures as an axisymmetric structure.

Two horizontal edges of the square window structure exceed the connecting positions of the two horizontal edges and the two vertical edges by a certain distance.

And each horizontal side of the square window structure takes the vertical part of the I-shaped structure as a symmetry axis.

The dielectric layer is a polyimide film with a dielectric constant of 2.88 and a loss tangent of 0.0032.

The three-band topological metamaterial terahertz wave absorber has the advantages that the three-band topological metamaterial terahertz wave absorber is subjected to topology on the basis of the existing structure, and a single absorption peak can be converted into three absorption peaks; the bottom metal layer is of an all-metal structure, and by adopting the structure, the transmission of electromagnetic waves can be avoided, and the electromagnetic waves entering the wave absorber are completely lost under the action of dielectric loss and ohmic loss; the whole structure is simple, the thickness is ultrathin, the integration is facilitated, the flexibility is realized, the thickness of the middle medium layer is 8 micrometers, the whole thickness is 8.3 micrometers, the absorption rates of the last two absorption bands reach 99.2 percent and 99.9 percent, and the perfect absorption is approximate; with wide incident angle characteristics, more than 90% of the absorption rate can still be maintained at 1.29THz and 1.59THz frequencies when the incident angle is increased to 60 degrees.

Drawings

FIG. 1 is a three-dimensional schematic diagram of a wave absorbing unit of a three-band topological metamaterial terahertz wave absorber;

FIG. 2 is a front view of a wave absorbing unit of a three-band topological metamaterial terahertz wave absorber;

FIG. 3 is a real object diagram of a three-band topological metamaterial terahertz wave absorber of the invention;

FIG. 4 shows the THz wave absorption rate of the three-band topological metamaterial terahertz wave absorber;

FIG. 5 shows the absorption rate of the THz wave in the three-band topological metamaterial terahertz wave absorber.

In the figure, 1 is a metal layer, 2 is a dielectric layer, and 3 is a metal microstructure unit layer.

Detailed Description

The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

The structure of the three-band topological metamaterial terahertz wave absorber is shown in figures 1-3 and comprises a plurality of wave absorbing units which are sequentially arranged, wherein each wave absorbing unit comprises a metal layer 1, a dielectric layer 2 and a metal microstructure unit layer 3 from the bottom layer to the top layer, the three layers of structures are tightly attached, and three absorption peaks are formed in a terahertz band.

The metal microstructure unit layer 3 comprises three parts which are connected with each other on the same plane, and the specific structure is as follows: the window comprises a pair of I-shaped structures which are symmetrically arranged, one of two horizontal edges of each I-shaped structure is shorter than the other edge, the short edges of the two I-shaped structures are symmetrical along a horizontal line, the vertical parts of the two I-shaped structures are also covered with a square window structure, and the square window structure takes the symmetrical axis of the short edges of the two I-shaped structures as an axisymmetric structure.

The dielectric layer 2 is a polyimide film with a dielectric constant of 2.88 and a loss tangent of 0.0032 and a thickness of 8 μm, and the metal layer 1 and the metal microstructure unit layer 3 have an electrical conductivity of 5.8 × 10⁷S/m and thickness are both 0.15 μm.

The invention relates to a three-band topological metamaterial terahertz wave absorber, which has a corresponding lattice constant g of 120 mu m, and the rest parameter structures are a of 12 mu m, b of 18.5 mu m, c of 6 mu m, d of 50 mu m, e of 78 mu m, f of 59 mu m, h of 3 mu m, w of 5 mu m, and j of 22 mu m; the metal layer 1 and the metal microstructure unit layer 3 are closely attached to the surface of the dielectric layer 2, and the centers of the metal layer and the metal microstructure unit layer are at the same point. FIG. 3 is a pictorial representation of an optical microscope of the present invention. Fig. 4 is a graph showing absorption characteristics of the THz band in the TE mode according to the present invention, and the absorptance of the present invention is 83.2%, 99.2% and 99.9% at the frequencies of 0.59THz, 1.29THz and 1.59THz, respectively, as shown in fig. 4. Fig. 5 is an absorption characteristic curve of the three-band topological metamaterial absorber provided by the invention under different incident angles, and as can be seen from fig. 5, the three-band topological metamaterial absorber still maintains good absorption characteristics to oblique-angle incidence at an absorption frequency point, and when the incident angle is increased to 60 degrees, the absorption rate is still maintained to be more than 90% at the frequencies of 1.29THz and 1.59THz, so that the absorption capacity of the device under large-angle oblique incidence can be met.

The three-band topological metamaterial terahertz wave absorber has potential application in the fields of near-field detection, imaging, communication and the like.

Claims

1. The utility model provides a three wave band topology metamaterial terahertz wave absorber which characterized in that, forms including a plurality of ripples unit arranges in order, every ripples unit is in proper order for metal level (1), dielectric layer (2) and metal microstructure unit layer (3) from the bottom to the top layer to every ripples unit, and three layer construction closely laminates, realizes that there is three absorption peak at terahertz wave band, metal microstructure unit layer (3) include three parts of coplanar interconnect, and concrete structure is: the window comprises a pair of I-shaped structures which are symmetrically arranged, one of two horizontal edges of each I-shaped structure is shorter than the other edge, the short edges of the two I-shaped structures are symmetrical along a horizontal line, the vertical parts of the two I-shaped structures are also covered with a square window structure, and the square window structure takes the symmetrical axis of the short edges of the two I-shaped structures as an axisymmetric structure.

2. The terahertz wave absorber of the three-band topological metamaterial according to claim 1, wherein two horizontal sides of the square window structure exceed the connecting positions of the two horizontal sides and two vertical sides by a distance.

3. The three-band topological metamaterial terahertz wave absorber of claim 2, wherein each horizontal side of the square window structure is symmetrical about a vertical portion of the I-shaped structure.

4. The terahertz wave absorber with the three-band topological metamaterial according to any one of claims 1 to 3, wherein the dielectric layer (2) is a polyimide film with a dielectric constant of 2.88 and a loss tangent of 0.0032.