Chiral-Gain Photonics

TL;DR

This paper explores electrically biased chiral-gain materials with nonreciprocal electromagnetic responses, demonstrating their potential to enable novel laser devices, polarization control, and high-Q cavity excitation by bypassing reciprocity constraints.

Contribution

It introduces the concept of chiral-gain in materials and shows how this property can be used to develop new electromagnetic devices with unique functionalities.

Findings

Chiral-gain materials can be active or dissipative based on wave polarization.

Chiral-gain enables the creation of chiral lasers and polarization-dependent mirrors.

Materials with chiral-gain can excite high-Q cavities beyond reciprocity limits.

Abstract

Here, we present an exploratory study of the potential applications of electrically biased materials that possess a nonreciprocal and non-Hermitian electromagnetic response analogous to the electronic response of field-effect transistors. The most distinctive feature of such materials is their chiral-gain, meaning that their response can be active or dissipative depending on the handedness of the wave polarization. Here, we show how the chiral-gain can be harnessed to develop novel electromagnetic devices with unique properties such as chiral lasers, polarization-dependent mirrors, and coherent-perfect-absorber lasers. Furthermore, it is demonstrated that materials with chiral-gain can bypass a reciprocity constraint that typically limits the external coupling strength, thus facilitating the excitation of cavities with extremely large quality factors.