The research of THz enhancement transmittance based on metamaterials

THz parametric oscillators (TPOs) based on phonon-polariton scattering in a LiNbO₃ crystal are one of promise methods of obtaining high power tunable THz radiation. However, how to effectively reduce the absorption and enhance the transmittance of terahertz (THz) in LiNbO₃ still remains a question. In this paper, we present a numerical simulation solution of antireflection coating using metamaterials based on Lithium niobate substrates. This structure effectively reduces the reflection and enhances the transmission near a specifically designed terahertz (THz) frequency band. Nearly 1.7% of reflection rate and over 94.7% of transmission rate are obtained near 1.2~1.3 THz. Such a design can promote THz wave, which has been generated in or pass through Lithium niobate, to radiate to outside space.