Manipulation of Entangled Photon Pairs in Sandwich Valley Photonic Crystals

We propose a sandwich valley photonic crystal implementing the generation and topological transport of continuous frequency entangled biphotons. These extended valley kink states propagating in the sandwich domain show more tolerance for disorders.

1. Introduction

Topological edge states provide a practicable way to conduct the topological transport of quantum states. The topological protection of topological edge states brings many applicable approaches, including topological quantum emitters [1], topological quantum interference [2], and topological biphoton states [3]- [4].