Engineering rainbow trapping and releasing in valley photonic crystal with electro-optical material

Abstract

Topological photonic insulators provide a robust platform for controlling the flow of light. Here, we propose a method to realize slow light rainbow trapping and releasing based on valley photonic crystals, which is created by gradually increasing the structure parameter. The edge waves of different frequencies are spatially separated and trapped at different positions to form topological rainbow trapping. Furthermore, the system is constructed by electric-optical material whose refractive index is tuned by applied voltages. Therefore, the switchable between slow light trapping states and releasing states can be realized by tuning the external voltage. The position where the wave stops propagating is given by theoretical analysis and numerical simulation. These results offer a novel, to the best of our knowledge, scheme for realizing multi-frequency routing. Such a structure could find application prospects in optical buffers, optical storage, and other optical communication devices.