Waveguide photonic limiters based on topologically protected resonant modes

TL;DR

This paper introduces topologically protected waveguide photonic limiters that leverage defect states for high transmission at low intensities and high reflectivity at high intensities, enhancing damage thresholds.

Contribution

It presents a novel concept of chiral photonic limiters based on topologically protected defect modes, with experimental validation using dielectric microwave resonators.

Findings

High resonant transmission at low intensity due to topological protection

Suppression of localized modes at high intensity increases reflectivity

Experimental demonstration with dielectric microwave resonator waveguide

Abstract

We propose a concept of chiral photonic limiters utilising topologically protected localised midgap defect states in a photonic waveguide. The chiral symmetry alleviates the effects of structural imperfections and guaranties a high level of resonant transmission for low intensity radiation. At high intensity, the light-induced absorption can suppress the localised modes, along with the resonant transmission. In this case the entire photonic structure becomes highly reflective within a broad frequency range, thus increasing dramatically the damage threshold of the limiter. Here we demonstrate experimentally the principle of operation of such photonic structures using a waveguide consisting of coupled dielectric microwave resonators.