Large absolute bandgap square lattice photonic crystal based on single-link column and ring column

Abstract

Provided is a large absolute band-gap square-lattice photonic crystal based on single-rod cylinders and circular cylinders, comprising a high-refractive-index medium cylinder and a low-refractive-index background medium cylinder. The high-refractive-index medium cylinder is constituted by a circular cylinder and a flat medium single rod. The flat single rod is parallel to the horizontal lattice vector or vertical lattice vector of the square lattice cell. The cells of the photonic crystal structure are arranged according to the square lattice. The crystal constant of the square lattice photonic crystal is a. The width D of the flat medium cylinder is 0.048a, the outer diameter R of the circular cylinder is 0.27a, the ratio T of the difference between the inner and outer diameters of the circular cylinder to the circular outer diameter is 0.296, and the relative value of the photonic crystal structure absolute band gap width is 9.8177%. The photonic crystal structure has a very large absolute band gap, and is widely applicable to the design of large-scale integrated optical circuits.

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 square lattice photonic crystal with a large absolute band gap has become the goal that people have been pursuing

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