Study Of The Transmission Property Of Photonic Crystal On Terahertz Band

Terahertz’s spectrum contains a lot of useful information and plays an important role when exploring the material structure. However, there is a strong absorption when THz waves transmit in the air, so it needs a particular transmission medium. The photonic crystal is a kind of periodic dielectric material with photonic band gap which has a unique function of regulating photon propagation state. It can be used to control the transmission of THz waves.In this paper, it based on a design of three-dimensional photonic crystal structure on THz band, used finite-difference time-domain to simulation study the factors which influence photonic band gap of three-dimensional photonic crystal such as cell cycles, lattice constant, dielectric constant, cell shape and size. The result shows that the number of periods increased will help reflect the characteristic of photonic band gap; with the larger lattice constant band gap gradually narrowed, band center position red-shifted; with the dielectric constant difference increased, the band effect was more obvious; with photonic crystal dielectric ball size increased, the band gap became wider, the position of center band changed little; in the same fill rate and dielectric material property conditions, with the lower symmetry of the media unit, the position of center band red-shifted.