Non-Hermitian polariton-photon coupling in a perovskite open microcavity

TL;DR

This paper demonstrates a perovskite-based double microcavity system that exhibits non-Hermitian properties, including nonreciprocal behavior and exceptional points, useful for tunable photonic devices through strong light-matter coupling.

Contribution

It introduces a novel perovskite microcavity system that naturally forms a double microcavity with non-Hermitian properties, supported by experimental and theoretical analysis.

Findings

Observation of double-coupled polariton modes with multiple inflection points

Demonstration of nonreciprocal properties due to non-Hermiticity

Identification of exceptional points in the system

Abstract

Exploring the non-Hermitian properties of semiconductor materials for optical applications is at the forefront of photonic research. However, the selection of appropriate systems to implement such photonic devices remains a topic of debate. In this work, we demonstrate that a perovskite crystal, characterized by its easy and low-cost manufacturing, when placed between two distributed Bragg reflectors with an air gap, can form a natural double microcavity. This construction shows promising properties for the realisation of novel, tunable non-Hermitian photonic devices through strong light-matter coupling. We reveal that such a system exhibits double-coupled polariton modes with dispersion including multiple inflection points. Owing to its non-Hermiticity, our system exhibits nonreciprocal properties and allows for the observation of exceptional points. Our experimental studies are in agreement with the theoretical analysis based on coupled mode theory and calculations based on transfer matrix method.