Exceptional points in anisotropic planar microcavities

TL;DR

This paper investigates how in-plane optical anisotropy in a uniaxial planar microcavity leads to the formation of exceptional points in the dispersion relation, revealing new polarization phenomena related to non-Hermitian physics.

Contribution

It demonstrates the emergence of exceptional points in anisotropic microcavities due to in-plane optical anisotropy, linking them to polarization vortices and non-Hermitian effects.

Findings

Exceptional points occur pair-wise and are circularly polarized.

These points are cores of polarization vortices.

The phenomena are related to the non-Hermitian nature of the system.

Abstract

Planar microcavities allow the control and manipulation of spin-polarization, manifested in phenomena like the optical spin Hall effect due to the intrinsic polarization mode splitting. Here, we study a transparent microcavity with broken rotational symmetry, realized by aligning the optical axis of a uniaxial cavity material in the cavity plane. We demonstrate that the in-plane optical anisotropy gives rise to exceptional points in the dispersion relation, which occur pair-wise, are circularly polarized, and are cores of polarization vortices. These exceptional points are a result of the non-Hermitian character of the system, and are in close relationship to singular optical axes in absorptive biaxial systems.