CN-120652582-B - Non-hermitian super-structured surface for short-interval wavelength division multiplexing and optical system

CN120652582BCN 120652582 BCN120652582 BCN 120652582BCN-120652582-B

Abstract

The invention provides a non-early super-structure surface and an optical system for short-interval wavelength division multiplexing, wherein the super-structure surface is provided with a plurality of super cells, each super cell is sequentially provided with a first metal layer, an insulating layer and a second metal layer, the overlooking angle of the super cell is square, the second metal layer is provided with a first metal body and a second metal body, the first metal body and the second metal body are cuboid, the first metal body and the second metal body are respectively arranged on two sides of the center of gravity of the overlooking plane of the super cell, and a first inclination angle is arranged between a straight line of the length direction of the first metal body and the length direction of the first metal body in the overlooking plane of the super cell. According to the scheme, independent phase regulation and control are respectively realized by utilizing the characteristic that non-Hermite singular points (Exceptional point, EP) move along with the wavelength in a parameter space of the gold double-rod unit structure.

Inventors

GUI LILI
CHEN HAO
XU YIYUAN
XU KUN

Assignees

北京邮电大学

Dates

Publication Date: 20260505
Application Date: 20250618

Claims (7)

1. A non-hermitian super structure surface for short-interval wavelength division multiplexing, wherein the super structure surface is provided with a plurality of super cells, each super cell is sequentially provided with a first metal layer, an insulating layer and a second metal layer, and the top view angle of the super cell is cube; the second metal layer is provided with a first metal body and a second metal body, the first metal body and the second metal body are cuboid, the first metal body and the second metal body are respectively arranged at two sides of a center of gravity point of a top plane of the super cell, and a first inclination angle is arranged between the width direction of the first metal body and the length direction of the second metal body in the top plane of the super cell; a second inclination angle exists between a connecting line of the gravity center points of the first metal body and the second metal body and the gravity center point of the top plane of the super cell and an edge line of the top plane of the super cell; The method comprises the steps of obtaining a first target wavelength and a second target wavelength, obtaining a corresponding first phase diagram and a second phase diagram, determining a corresponding first phase based on the position of a super cell on a super-constructed surface and against a preset first phase diagram, calculating a second inclination angle of the super cell based on the first phase diagram, determining a corresponding second phase based on the position of the super cell on the super-constructed surface and against a preset second phase diagram, calculating a phase shift value at a non-Hermite singular point wavelength based on the first phase diagram and the second phase diagram, determining the length and the width of the second metal body in the super cell based on the phase shift value at the non-Hermite singular point wavelength, and calculating the second inclination angle and the phase shift value at the non-Hermite singular point wavelength according to the following formula: ; Wherein, the Indicating the angle of the second inclination angle, A first phase is indicated and a second phase is indicated, Representing the phase shift value at the non-hermitian singular point wavelength, Representing the second phase.
2. The non-hermitian super structure surface for short-interval wavelength division multiplexing according to claim 1, wherein the length, width and height of the first metal body of each super cell are the same at the super structure surface, and the height of the second metal body is the same as the height of the first metal body.
3. The non-hermitian super structure for short-interval wavelength division multiplexing according to claim 2, wherein the length of the first metal body ranges from 350 to 400nm, the width of the first metal body ranges from 80 to 120nm, and the height of the first metal body ranges from 120nm.
4. The non-hermite super-structured surface for short-space wavelength division multiplexing according to claim 1, wherein, in a top-view plane of the super cell, the distances of the center of gravity points of the first metal body and the second metal body from the center of gravity point of the top-view plane of the super cell are both first distances.
5. A non-hermite super-structured surface for short-space wavelength division multiplexing according to claim 3, wherein, in a top-view plane of the super cell, the center of gravity points of the first metal body and the second metal body are in the same straight line as a center of gravity point connecting line of the top-view plane of the super cell.
6. The non-hermitian super structure for short-interval wavelength division multiplexing according to claim 2, wherein the second metal body has a length ranging from 300 to 500nm and a width ranging from 100 to 300nm.
7. An optical system employing a non-hermitian super structured surface for short-interval wavelength division multiplexing as claimed in any one of claims 1 to 6.

Description

Non-hermitian super-structured surface for short-interval wavelength division multiplexing and optical system Technical Field The invention relates to the technical field of optics, in particular to a non-hermitian super-structured surface for short-interval wavelength division multiplexing and an optical system. Background In recent years, the multifunctional characteristics of the super-structured surface become the hot spot direction in the research field of the super-structured surface, and the characteristic of being capable of realizing multiple optical functions at the same time attracts a great deal of attention. Compared with the traditional single-function super-structured surface, the multifunctional super-structured surface not only can more efficiently utilize the space resources of the optical device, but also can remarkably improve the integration level and the functionality of the system. Common multifunctional super-structured surfaces include multiplexed super-structured surfaces of polarization, wavelength and angle of incidence. The wavelength multiplexing method takes each wavelength as an independent channel, simultaneously transmits or processes a plurality of different information, and the channels are mutually independent, so that the method can be used for parallel data transmission, multichannel optical communication and information storage density improvement of information transmission and processing efficiency. This approach has proven to be effective in enhancing the performance of communication and encryption systems and can be further enhanced by increasing the number of reusable wavelengths (reducing the wavelength interval) within the system operating band. Traditional wavelength multiplexing methods include independent regulation and control of multiple wavelengths by using neural networks and algorithm aided design, combining polarization multiplexing, space division and other methods, and the wavelengths for multiplexing are usually more than 50nm apart. This is because current superstructural surface materials lack the desired diversity in optical properties over multiple wavelength ranges, such as in particular communication bands, imaging bands, etc., and commonly used amorphous silicon and titanium dioxide materials do not provide differentiated optical parameters such as refractive index, reflectivity, etc. In a multi-wavelength multiplexing system, light beams with different wavelengths need to be accurately and effectively regulated, and the limitation of the materials can not achieve the aim of the super-structured surface, so that the super-structured surface is prevented from realizing functional diversity in wavelength multiplexing research. Disclosure of Invention In view of the foregoing, embodiments of the present invention provide a non-hermitian super-structured surface and an optical system for short-space wavelength division multiplexing that obviate or ameliorate one or more of the disadvantages of the prior art. One aspect of the present invention provides a non-hermite super-structured surface for short-space wavelength division multiplexing, the super-structured surface being provided with a plurality of super cells, each super cell being sequentially provided with a first metal layer, an insulating layer and a second metal layer, the super cells having a square top view angle; The second metal layer is provided with a first metal body and a second metal body, the first metal body and the second metal body are cuboid, the first metal body and the second metal body are respectively arranged on two sides of a gravity center point of a top plane of the super cell, and a first inclination angle is arranged between a straight line where the length direction of the first metal body is located and the length direction of the first metal body in the top plane of the super cell. By adopting the scheme, the wavelength multiplexing super-structured surface with short wavelength interval is realized by utilizing the characteristic that non-Hermite singular points (Exceptional point, EP) move along with the wavelength in the parameter space of the gold double-rod unit structure. The unit structure geometric parameters forming the super-structure surface are selected around the EP in the parameter space, and the structure is integrally rotated by combining a geometric phase mechanism. In some embodiments of the present invention, the metal material used for the first metal layer and the second metal layer is gold, and the insulating layer is silicon dioxide. In some embodiments of the invention, the length, width and height of the first metal body of each super cell are the same at the super structured surface, and the height of the second metal body is the same as the height of the first metal body. In some embodiments of the present invention, the length of the first metal body ranges from 350 to 400nm, the width of the first metal body ranges from 80 to 120nm