Unidirectional transmission of visible region topological edge states in hexagonal boron nitride valley photonic crystals
Min Wu, Yibiao Yang, Hongming Fei, Han Lin, Yuhui Han, Xiaodan Zhao, Zhihui Chen
Abstract
Here we theoretically design valley photonic crystals (VPCs) based on two-dimensional (2D) hexagonal boron nitride (hBN) materials, which are able to support topological edge states in the visible region. The edge states can achieve spin-dependent unidirectional transmission with a high forward transmittance up to 0.96 and a transmission contrast of 0.99. We further study the effect of refractive index on transmittance and bandwidth, and it is found that with the increase of refractive index, both transmittance and bandwidth increased accordingly. This study opens new possibilities in designing unidirectional transmission devices in the visible region and will find broad applications.