Frequency-dependent topological phases and photonic detouring in valley photonic crystals

TL;DR

This paper introduces frequency-dependent topological phases in valley photonic crystals, demonstrating broadband photonic detouring and potential applications in wavelength division multiplexers.

Contribution

It develops an effective Hamiltonian for dual band gaps and reveals all four topological phases in metallic valley photonic crystals, enabling frequency-dependent control.

Findings

All four topological phases are identified in metallic valley photonic crystals.

Frequency-dependent edge states are demonstrated at domain walls.

A broadband photonic detouring mechanism is proposed.

Abstract

Here, the frequency degree of freedom is introduced into valley photonic crystals with dual band gaps. Based on the high-order plane wave expansion model, we derive an effective Hamiltonian which characterizes dual band gaps. Metallic valley photonic crystals are demonstrated as examples in which all four topological phases are found. At the domain walls between topologically distinct valley photonic crystals, frequency-dependent edge states are demonstrated and a broadband photonic detouring is proposed. Our findings provide the guidance for designing the frequency-dependent property of topological structures and show its potential applications in wavelength division multiplexers.