Electromagnetically induced transparency at a chiral exceptional point

TL;DR

This paper explores how chiral optical states at exceptional points in a resonator system can be used to control transparency and absorption, enabling advanced manipulation of light flow with potential applications in optical computing and storage.

Contribution

It introduces a novel method to manipulate light by tuning resonators to exceptional points, exploiting chirality for optical state control in photonic systems.

Findings

Transparency or absorption depends on chirality at the exceptional point

Experimental demonstration of chirality-dependent optical states

Potential for controlling slow light and quantum information processing

Abstract

Electromagnetically induced transparency, as a quantum interference effect to eliminate optical absorption in an opaque medium, has found extensive applications in slow light generation, optical storage, frequency conversion, optical quantum memory as well as enhanced nonlinear interactions at the few-photon level in all kinds of systems. Recently, there have been great interests in exceptional points, a spectral singularity that could be reached by tuning various parameters in open systems, to render unusual features to the physical systems, such as optical states with chirality. Here we theoretically and experimentally study transparency and absorption modulated by chiral optical states at exceptional points in an indirectly-coupled resonator system. By tuning one resonator to an exceptional point, transparency or absorption occurs depending on the chirality of the eigenstate. Our results demonstrate a new strategy to manipulate the light flow and the spectra of a photonic resonator system by exploiting a discrete optical state associated with specific chirality at an exceptional point as a unique control bit, which opens up a new horizon of controlling slow light using optical states. Compatible with the idea of state control in quantum gate operation, this strategy hence bridges optical computing and storage.