Unidirectional transmission of visible region topological edge states in hexagonal boron nitride valley photonic crystals

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. (c) 2022 Optical Society of America under the terms of the OSA Open Access Publishing Agreement

Automated summary

We theoretically designed valley photonic crystals (VPCs) based on two-dimensional hexagonal boron nitride (hBN) materials and demonstrated their ability to support topologically protected edge states in the visible region. These edge states enable spin-dependent unidirectional transmission with high transmittance and contrast. We also investigated the effect of refractive index on transmittance and bandwidth, and found that increased refractive index leads to improved performance. This study opens up new possibilities for designing unidirectional transmission devices in the visible region and has broad applications.