Selective enhancement of topologically induced interface states in a dielectric resonator chain

TL;DR

This paper demonstrates how topologically induced defect states in dielectric resonator chains can be selectively enhanced using non-Hermitian symmetries, improving their robustness and visibility in optical systems.

Contribution

It introduces a method to enhance topological defect states in dielectric resonator chains by leveraging non-Hermitian symmetries that break sublattice symmetry, improving their robustness.

Findings

Defect states are isolated from losses respecting parity-time symmetry.

Enhanced visibility of defect states in frequency and time domains.

Method applicable to various optical platforms including lasers and couplers.

Abstract

The recent realization of topological phases in insulators and superconductors has advanced the quest for robust quantum technologies. The prospects to implement the underlying topological features controllably has given incentive to explore optical platforms for analogous realizations. Here we realize a topologically induced defect state in a chain of dielectric microwave resonators and show that the functionality of the system can be enhanced by supplementing topological protection with non-hermitian symmetries that do not have an electronic counterpart. We draw on a characteristic topological feature of the defect state, namely, that it breaks a sublattice symmetry. This isolates the state from losses that respect parity-time symmetry, which enhances its visibility relative to all other states both in the frequency and in the time domain. This mode selection mechanism naturally carries over to a wide range of topological and parity-time symmetric optical platforms, including couplers, rectifiers and lasers.