Square-lattice photonic crystals based on high-refractive-index inner-circle-outer-square hollow cylinders

Abstract

A square crystal lattice photonic crystal based on a high refractive index hollow column with a round inner surface and a square outer surface. The cell of the photonic crystal is composed of a high refractive index hollow column with a round inner surface and a square outer surface and a low refractive index background medium. The photonic crystal structure is formed by arranging the high refractive index hollow columns and medium square columns with round inner surfaces and square outer surfaces in a low refractive index medium background according to a square crystal lattice. The lattice constant of the photonic crystal square crystal lattice is a. The side length of the outer square of the hollow column is 0.74013a, the rotation angle of the medium column is 27.264, the radius of the inner round hole is 0.3119a, and the corresponding relative value of the maximum absolute forbidden band is 18.184%. The photonic crystal belongs to a square crystal lattice, so that the connection and coupling between different optical elements in an optical path and between different optical paths can be realized easily, and the reduction of the cost is facilitated. The photonic crystal structure has a very large absolute forbidden band, and can be widely applied to the design of the large-scale integrated optical path.

Description

technical field [0001] The invention relates to a two-dimensional photonic crystal with wide absolute forbidden band. Background technique [0002] In 1987, E. Yablonovitch of Bell Laboratories in the United States was discussing how to suppress spontaneous emission, and S. John of Princeton University was discussing the photonic region and independently proposed the concept of photonic crystal (Photonic Crystal). A photonic crystal is a material structure in which dielectric materials are periodically arranged in space, and is usually an artificial crystal composed of two or more materials with different dielectric constants. [0003] In the frequency domain, for TE or TM waves propagating in any direction, the frequency interval where the electromagnetic field density of states is zero is defined as the TE or TM complete band gap of the photonic crystal, and the frequency interval where both TE and TM are completely forbidden is called a photonic crystal absolute ban. De...

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Problems solved by technology

[0005] Traditionally, in order to obtain a large relative forbidden band, non-square lattice structures such as triangular lattice and hexagonal lattice need to be used. However, in the photonic crystal integrated optical path, the use of square lattice structure can make the optical path simple and easy to improve the optical path. Integration, while the absolute band gap of the traditional square lattice photonic crystal is very small, so the formation of a square lattice photonic crystal with a large absolute band gap is the goal that people have been pursuing.

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