A low-loss broadband terahertz wave graded photonic crystal filter

Abstract

The present invention provides a low-loss wideband terahertz wave gradient photonic crystal filter. The filter comprises a two-dimensional photonic crystal; different circular silicon dielectric columns are arranged periodically in a square lattice manner so as to form the two-dimensional photonic crystal; the middle of the two-dimensional photonic crystal is provided with a resonant cavity; the resonant cavity is composed of three dielectric columns; an input channel, an output channel and the resonant cavity are located on a horizontal line to form a terahertz wave transmission channel; the dielectric columns are evenly distributed at the upper side and lower side of the terahertz wave transmission channel and form a symmetrical structure; the sizes of the dielectric columns in the same row are identical; the radiuses of the dielectric columns are gradually increased from center to edge; and when terahertz waves arrives at the resonant cavity through the input channel, terahertz waves according with the resonant frequency of the resonant cavity are coupled into the resonant frequency, so that coupled output is obtained, and wideband filtering in the frequency range of 380GHz to 438GHz can be realized.

Description

technical field [0001] The invention relates to a terahertz passive filter technology, in particular to a low-loss, wide-band filter of a two-dimensional photonic crystal. Background technique [0002] Terahertz waves are between millimeter waves and infrared light, with frequencies in the range of 0.1THz to 10THz, and corresponding wavelengths in the range of 3mm to 30μm. At present, the terahertz wave frequency band has not been allocated, which can provide huge broadband resources for future high-capacity and high-speed communications. Photonic crystals are a new type of optical microstructure formed by periodic arrangement of dielectric materials with different refractive indices in space. It has photon locality. When defects or dielectric disorder are introduced into photonic crystals, the original symmetry and periodicity of photonic crystals will be broken, and defect states will appear in the photonic band gap, which coincides with the frequency of defect states. T...

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Problems solved by technology

However, the response frequency band of most photonic crystal filters is not in the terahertz atmospheric communication window, so that it cannot be applied to the terahertz atmospheric communication system, and the application is limited; according to the research progress at home and abroad, the terahertz wave photonic crystal filter The bandwidth is relatively narrow, and it is difficult to adapt to the requirements of broadband and ultra-high-speed communication. This is also one of the key problems that researchers are eager to solve.

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