CN-122018061-A - Perimeter-variable unidirectional coupling topological photonic cavity based on scatterer

CN122018061ACN 122018061 ACN122018061 ACN 122018061ACN-122018061-A

Abstract

The invention discloses a perimeter-variable unidirectional coupling topological photonic cavity based on a scatterer. The invention comprises a shielding cover, a spin-on continuous medium layer and an air layer, wherein chiral surface states exist at the junction of the shielding cover and the air layer, a cylindrical spin-on continuous medium is also arranged in the air layer, a first scatterer of an isotropic medium exists between the air layer and the interface of the cylindrical spin-on continuous medium layer and the chiral surface states, and air exists at the junction of the first scatterer, the cylindrical spin-on continuous medium layer and the chiral surface states. The unidirectional coupling topological photonic cavity with the variable perimeter is free from dependence on strict periodic conditions, and can realize unidirectional coupling effect under the condition of photonic cavities with different perimeters. The unidirectional coupling between the chiral boundary state and the scatterer is closely related to the direction of an externally applied magnetic field in the gyrotron continuous medium while the transmission characteristic of the chiral boundary state scattering inhibition is realized. Further, the unidirectional coupling topological photon cavity with variable circumference and controllable coupling direction is realized by changing the radius size and the magnetic field direction of the photon cavity.

Inventors

WANG KUNPENG
HAN NING
LI MINGZHU
LI CHENXIA
FENG GUILAN
ZHU QI
ZHAO RUI

Assignees

中国计量大学
浙大城市学院

Dates

Publication Date: 20260512
Application Date: 20260210

Claims (10)

1. The circumference-variable unidirectional coupling topological photonic cavity based on the scatterer is characterized by comprising a shielding cover and a spiral electric continuous medium layer and an air layer which are respectively arranged in the shielding cover, wherein chiral surface states exist at the juncture of the spiral electric continuous medium layer and the air layer; at least one cylindrical spin-on continuous medium is also arranged in the air layer, and a first scatterer of an isotropic medium exists between the cylindrical spin-on continuous medium and an interface where the chiral surface state is located; Air is present at the junction of the first scatterer, the cylindrical gyratory continuous medium and the chiral surface state.
2. The diffuser-based variable perimeter unidirectional coupling topological photonic cavity of claim 1, further comprising an excitation point source disposed at an interface location where the chiral surface states reside.
3. The scatterer-based variable perimeter unidirectional coupling topology photonic cavity of claim 1, further comprising a cylindrical air cavity disposed within the gyrostatic continuous medium layer.
4. A variable perimeter unidirectional coupling topological photonic cavity based on a scatterer as claimed in claim 3, wherein a second scatterer of isotropic medium is further present between the interface of the cylindrical air cavity and the chiral surface state, and a gyrostatic continuous medium is present between the interface of the second scatterer and the cylindrical air cavity and the chiral surface state.
5. The photonic cavity of the variable circumference unidirectional coupling topology based on the scatterer according to claim 1, wherein the chiral surface state generated at the junction of the gyrotron continuous medium layer and the air layer is coupled with the first scatterer, so as to realize the function of the unidirectional coupling photonic cavity.
6. A scatterer-based variable perimeter unidirectional coupling topology photonic cavity in accordance with claim 1, wherein said gyrostatic continuous medium is a bulk material that can be described by equivalent relative dielectric tensors and permeability tensors, with non-trivial topological response induced by non-zero gyrostatic parameters.
7. The scatterer-based variable perimeter unidirectional coupling topological photonic cavity of claim 1, wherein the interface between the gyrostatic continuous medium layer and the chiral surface state has defects.
8. The diffuser-based variable perimeter unidirectional coupling topological photonic cavity of claim 1, wherein the unidirectional coupling direction of the photonic cavity is controlled by changing the radius and magnetic field direction of a cylindrical gyratory continuous medium or a cylindrical air cavity.
9. The scatterer-based variable perimeter unidirectional coupling topological photonic cavity of claim 8, wherein the unidirectional coupling efficiency of the photonic cavity is adjusted by adjusting the radius of a cylindrical gyratory continuous medium or a cylindrical air cavity under the condition of constant magnetic field conditions and constant operating frequency.
10. The scatterer-based variable perimeter unidirectional coupling topology photonic cavity of claim 8, wherein the unidirectional coupling direction of the photonic cavity is changed by changing the direction of the magnetic field with the radius and operating frequency of the cylindrical gyratory continuum or cylindrical air cavity unchanged.

Description

Perimeter-variable unidirectional coupling topological photonic cavity based on scatterer Technical Field The invention belongs to the technical field of optical devices, relates to a topological device for inducing a photon cavity based on a coupling effect between an optical waveguide mode and a scatterer, and particularly relates to a perimeter-variable unidirectional coupling topological photon cavity based on a scatterer. Background The study of topological photonics originates from the discovery of topological phases in condensed state physics and has evolved into the leading direction of interdigitating and fusing topological physics with photonics fields. In recent years, a series of developments on topological phases in topological photonics, such as outer points, topological insulators, chiral states and the like, and topological photonics devices which realize different functions based on chiral surface state designs in the topological phases, such as topological photon waveguides, topological photon beam splitters and topological photon cavities, provide a new scheme for scattering and inhibiting light transmission. In recent years, different types of topological photon cavities are designed and realized based on a photonic crystal platform, for example, any shape topological photon cavity is realized in a system with time reversal symmetry breaking, and a new regulation scheme is provided for the interaction of light and substances. However, photonic crystals often need to rely on strict periodic conditions and well-designed unit cell structures, thereby limiting the structural tunability of topological photonic cavities. Unlike the photonic crystals described above, at long wavelength approximation, the gyrostatic continuous medium is a uniform bulk material described by a relative equivalent dielectric tensor and permeability tensor, and the non-zero gyrostatic parameter breaks the time-reversal symmetry. Furthermore, the undoubted topological properties in the gyrotron medium are induced by magneto-optical effects. In recent years, gyrotron continuous media have been studied in terms of application of topological photonic devices with different functions, such as designing topological photonic waveguides, topological photonic isolators, topological photonic beam splitters, and the like. However, at present, research means of unidirectional transmission topological photonic devices based on gyrotron continuous media are single, most of research is focused on topological photonic systems with single structures and specific structural dimensions, and few researches on topological photonic devices with interactions between chiral surface states and scatterers, adjustable circumferences and controllable coupling directions are reported, for example, a unidirectional coupling topological photonic cavity with variable circumferences is designed. Disclosure of Invention The invention aims at overcoming the defects of the prior art, and aims to provide a circumference-variable unidirectional coupling topological photonic cavity based on a scatterer, in particular to a topological photonic cavity capable of realizing circumference-variable and coupling direction-controllable, so as to provide a design scheme of a circumference-variable unidirectional coupling topological photonic cavity functional device. The invention provides a circumference-variable unidirectional coupling topological photonic cavity based on a scattering body, which comprises a shielding cover and a spiral electric continuous medium layer and an air layer which are respectively arranged in the shielding cover, wherein chiral surface states exist at the juncture of the spiral electric continuous medium layer and the air layer; at least one cylindrical spin-on continuous medium is also arranged in the air layer, and a first scatterer of an isotropic medium exists between the cylindrical spin-on continuous medium and an interface where the chiral surface state is located; Air is present at the junction of the first scatterer, the cylindrical gyratory continuous medium and the chiral surface state. Preferably, an excitation point source is also arranged at the interface position where the chiral surface state is located. Preferably, a cylindrical air cavity is also arranged in the cyclone continuous medium layer. More preferably, a second scatterer of isotropic medium is also arranged between the interface between the cylindrical air cavity and the chiral surface state, and a gyratory continuous medium is arranged between the second scatterer and the interface between the cylindrical air cavity and the chiral surface state. Preferably, the number of cylindrical air chambers is the same as or different from the number of cylindrical spin-on continuous media. Preferably, the chiral surface state generated at the junction of the gyrotron continuous medium layer and the air layer is coupled with the first scatterer, so that the photon cav