Microwave frequency band electromagnetic induced transparency structure

Abstract

The electromagnetic induced transparency structure of microwave frequency band of the present application belongs to the technical field of electromagnetic wave detection and sensor device, which is composed of hollow metal rectangle (1), solid metal rectangle (2) and dielectric layer (3). The hollow metal rectangle (1) and the solid metal rectangle (2) are arranged periodically in two directions perpendicular to each other on the same surface of the dielectric layer (3), the hollow metal rectangle (1) and the solid metal rectangle (2) are different by 45 degrees, and the midpoint of each side of the solid metal rectangle (1) is just in contact with a vertex of the hollow metal rectangle (2). The structure of the present application can realize electromagnetic induced transparency effect, the transmittance reaches more than 90%, and the polarization direction of the incident light does not affect the structure, which has the advantage of being insensitive to the incident angle, and the selected materials are mature in preparation technology and easy to manufacture.

Description

[0001] This invention belongs to the field of electromagnetic wave detection and sensor technology, and relates to an electromagnetically induced transparent structure that is independent of polarization in the microwave frequency band, and particularly to an electromagnetically induced transparent structure. Background Technology

[0002] Electromagnetically-induced transparency (EIT) is a crucial phenomenon in atomic physics. Essentially, under resonant conditions—that is, when the frequency of light matches the corresponding atomic transition frequency—quantum destructive coherence occurs between the excitation channels of photoatoms, resulting in a narrow transmission peak within a broad absorption band. EIT has also been applied to microwave and terahertz bands, where the phenomenon often manifests as a narrow transmission peak within a wide non-transmission band. EIT structures can alter dispersion properties and slow the speed of light, leading to important applications in nonlinear devices, slow-light devices, filters, sensors, and optical storage.

[0003] Microwaves refer to electromagnetic waves with frequencies between 300MHz and 300GHz. They are characterized by easy focusing into beams, high directionality, and straight-line propagation, making them suitable for transmitting high-frequency signals in unobstructed free space. Due to these characteristics, microwaves experience significant propagation loss in air, resulting in short transmission distances. However, they offer high mobility and a wide operating bandwidth. Besides millimeter-wave technology used in 5G mobile communications, microwave transmission is primarily conducted in metallic and dielectric waveguides.

[0004] In recent years, electromagnetically induced transparent devices in the terahertz band have attracted widespread attention. However, domestic and international research on electromagnetically induced transparent devices has mainly focused on the terahertz band, while there are relatively few electromagnetically induced transparent structures in the microwave band. Furthermore, existing electromagnetically induced transparent structures exhibit polarization-sensitive characteristics, often appearing only under one polarization mode, or the electromagnetically induced transparency phenomena corresponding to the two polarization modes are different. Summary of the Invention

[0005] The purpose of this invention is to provide an electromagnetically induced transparent structure to achieve electromagnetically induced transparency characteristics that are insensitive to polarization in the low-frequency band. The specific technical solution is as follows:

[0006] An electromagnetically induced transparent structure in the microwave band, comprising a hollow metal rectangle 1, a solid metal rectangle 2, and a dielectric layer 3, is characterized in that...

[0007] The hollow metal rectangle 1 and the solid metal rectangle 2 are on the same surface of the dielectric layer 3 and are periodically arranged in two mutually perpendicular directions. The hollow metal rectangle 1 and the solid metal rectangle 2 are 45 degrees apart, and the midpoint of each of the four sides of the solid metal rectangle 1 just touches one vertex of a hollow metal rectangle 2.

[0008] The hollow metal rectangle 1 is a square with a side length of L1 = 3.6 mm and the width of each side is w = 0.2 mm; the solid metal rectangle 2 is a square with a side length of L2 = 3.394 mm and the dielectric layer 3 has a thickness of h = 0.8 mm. The thickness of both the hollow metal rectangle 1 and the solid metal rectangle 2 is greater than 10 μm; the repetition period of the unit structure in two mutually perpendicular directions is P = 6 mm, and the hollow metal rectangle 1 and the solid metal rectangle 2 have similar plasmon resonance frequencies.

[0009] The hollow metal rectangle 1 and the solid metal rectangle 2 are made of gold, silver, copper or aluminum, with copper being preferred.

[0010] The relative permittivity of the dielectric layer 3 is 1.0 to 1.3, preferably 1.54.

[0011] This invention discloses a polarization-independent electromagnetically induced transparency structure in the microwave frequency band. This structure achieves electromagnetically induced transparency with a transmittance exceeding 90%, and the polarization direction of the incident light does not affect the structure, exhibiting the advantage of being insensitive to the incident angle. The materials used in the structure of this invention are all based on mature fabrication techniques and are easy to manufacture. Attached Figure Description

[0012] Figure 1 This is a three-dimensional structural diagram of an electromagnetically induced transparent structure in the microwave band according to the present invention: it consists of a hollow rectangular structure 1, a solid rectangular structure 2, and a dielectric layer 3.

[0013] Figure 2 This is a top view of an electromagnetically induced transparent structure in the microwave band according to the present invention: L1 represents the side length of the hollow rectangular structure, L2 represents the side length of the solid rectangular structure, the unit structure period P = 6mm, and w represents the width of the side of the hollow rectangle.

[0014] Figure 3 This is a periodic structure array diagram of an electromagnetically induced transparent structure in the microwave band according to the present invention, with incident light incident along the k-axis.

[0015] Figure 4 This is a transmission curve of the x or y line polarized wave of the structure in Embodiment 1 of the present invention. Detailed Implementation

[0016] The present invention will be further illustrated below with reference to specific embodiments.

[0017] Example 1

[0018] like Figures 1-3 As shown, the present invention discloses an electromagnetically induced transparent structure in the microwave band, comprising: a dielectric layer and a metal unit, wherein the device is an array structure.

[0019] The metal unit is composed of a hollow metal rectangle 1 and a solid metal rectangle 2;

[0020] The dielectric layer 3 has a relative permittivity of 1.0 to 1.3, and can be any one of organic polymer film, sapphire, quartz, silicon or silicon dioxide. In this embodiment, silicon dioxide with a permittivity of 1.54 is selected.

[0021] The metal unit can be gold, silver, copper or aluminum; in this embodiment, copper is used.

[0022] The hollow metal rectangle 1 has a side length of L1 = 3.6 mm and a side width of w = 0.2 mm; the solid metal rectangle 2 has a side length of L2 = 3.394 mm; the hollow metal rectangle 1 and the solid metal rectangle 2 have similar plasmon resonance frequencies.

[0023] The unit structure has a period of P = 6 mm, and the dielectric layer 3 has a thickness of h = 0.8 mm.

[0024] The thickness of the metal unit is greater than 10 μm, and in this embodiment, a thickness of s = 30 μm is used.

[0025] The hollow metal rectangle must be in perfect contact with the solid rectangle. The mathematical relationship is L2 = 2^(1 / 2)*(P-L1).

[0026] One method is to deposit a metal layer on the surface of the dielectric layer, and then remove part of the metal at intervals using techniques such as laser engraving or electron beam exposure, leaving only the metal unit portion.

[0027] When incident light of arbitrary polarization is incident perpendicularly on the structure, it will excite plasmon resonance in both the hollow and solid metal rectangular structures. A transparency peak will appear between the two plasmon resonance frequencies, which is the electromagnetically induced transparency effect.

[0028] The embodiments of the present invention, based on the combination of hollow metal rectangular structures and solid metal rectangular structures, can effectively achieve electromagnetically induced transparency characteristics that are insensitive to polarization in the low-frequency band, such as... Figure 4 Transmission curves of x- or y-polarized waves are given, showing that the transmittance of the electromagnetically induced transparent structure provided in the embodiments of the present invention can reach more than 90%. The materials used in this structure are all of mature preparation technology and easy to manufacture.

Claims

1. An electromagnetically induced transparent structure in the microwave band, comprising a hollow metal rectangle (1), a solid metal rectangle (2), and a dielectric layer (3); Its features are, The hollow metal rectangle (1) and the solid metal rectangle (2) are on the same surface of the dielectric layer (3) and are periodically arranged in two mutually perpendicular directions. The hollow metal rectangle (1) and the solid metal rectangle (2) are 45 degrees apart, and the midpoint of the four sides of each solid metal rectangle (2) touches one vertex of a hollow metal rectangle (1). The hollow metal rectangle (1) is a square with a side length of L1 = 3.6 mm and the width of each side is w = 0.2 mm; the solid metal rectangle (2) is a square with a side length of L2 = 3.394 mm and the dielectric layer (3) has a thickness of h = 0.8 mm. The thickness of both the hollow metal rectangle (1) and the solid metal rectangle (2) is greater than 10 μm; the repetition period of the unit structure in two mutually perpendicular directions is P = 6 mm, and the hollow metal rectangle (1) and the solid metal rectangle (2) have similar plasmon resonance frequencies; The hollow metal rectangle (1) and the solid metal rectangle (2) are made of gold, silver, copper or aluminum; The relative permittivity of the dielectric layer (3) is 1.0~1.

3.

2. The electromagnetically induced transparent structure in the microwave band according to claim 1, characterized in that, The hollow metal rectangle (1) and the solid metal rectangle (2) are made of copper.

Images