Wideband trapping of light by edge states in honeycomb photonic crystals

TL;DR

This paper demonstrates theoretically that edge states in honeycomb photonic crystals can be used to achieve wideband light trapping by tuning edge rod radii, enabling sharp spatial confinement of different frequencies.

Contribution

It introduces a method to achieve wideband light trapping in honeycomb photonic crystals through edge state engineering and graded edge rod radii.

Findings

Edge states exist within the photonic band gap with sharp confinement.

Tuning edge rod radius adjusts the dispersion of edge states.

Graded edge rods enable spatially separated trapping of different frequencies.

Abstract

We study theoretically light propagations at the zigzag edge of a honeycomb photonic crystal consisting of dielectric rods in air, analogous to graphene. Within the photonic band gap of the honeycomb photonic crystal, a unimodal edge state may exist with a sharp confinement of optical fields. Its dispersion can be tuned simply by adjusting the radius of the edge rods. For the edge rods with a graded variation in radius along the edge direction, we show numerically that light beams of different frequencies can be trapped sharply in different spatial locations, rendering wideband trapping of light.