Two-dimensional photonic crystal of linear gradually-changed structure

Abstract

A two-dimensional photonic crystal of a linear gradually-changed structure comprises a matrix made of a low-dielectric-constant material, and high-dielectric-constant material columns are embedded into the material of the matrix and distributed in a square in space periodically. The radiuses of the columns are linearly and gradually increased or reduced in the wave propagation direction at a certain step length, the radiuses of the columns are not changed in the direction perpendicular to the wave propagation direction, and the center distances of the columns in the two directions are lattice constants. By optimizing structural parameters, under the condition that the dielectric ratio is relatively low, the relative band gap width is nearly 200% that of a standard square structure; under the condition that the dielectric ratio is higher, the band gap width is 2-5 times that of the standard structure. Compared with a traditional structure, the band gap rate is greatly increased. Compared with other complex structures, design is simple, a user can select a required forbidden band range according to materials needing to be adjusted and the structural parameters, and important value is provided for design, manufacturing and application of the two-dimensional photonic crystal.

Description

technical field [0001] The invention relates to a photonic crystal with a two-dimensional linear gradient structure, belonging to the technical field of microwave photonic crystals. Background technique [0002] Photonic crystals refer to composite materials in which dielectrics are periodically arranged in three-dimensional space. According to the periodicity of dielectrics in the spatial arrangement direction, photonic crystals are divided into one-dimensional, two-dimensional, and three-dimensional photonic crystals. A general two-dimensional photonic crystal means that the dielectric constant in the plane of wave propagation is ε 1 A material with a dielectric constant ε 2 Periodically arranged in the material, so that the photonic bandgap material can be formed in two dimensions. [0003] Similar to the energy bands of semiconductors, when electromagnetic waves propagate in the periodic structure of photonic crystals, the electromagnetic waves are modulated due to per...

AI Technical Summary

Problems solved by technology

[0007] In summary, in the design of photonic crystals, the bandgap width of traditional photonic crystals is unsatisfactory, and complex structures such as complex structures or changing the cross-section of pillars are difficult to prepare. This invention designs a new photonic crystal structure, which improves both The wide band gap is easy to prepare, and the frequency range is expanded, laying a solid foundation for practical applications

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