Unconventional optical microcavities hosting multiple exceptional points

TL;DR

This paper demonstrates the creation of multiple exceptional points in an optical microcavity with tailored gain and loss, revealing unique topological and stability properties of coupled resonances in non-Hermitian systems.

Contribution

It introduces a novel scheme to realize and analyze multiple exceptional points in an optical microcavity with spatially varying gain and loss profiles.

Findings

Multiple EPs can be achieved via avoided crossing in microcavities.

Energy eigenvalues exhibit characteristic behaviors when encircling EPs.

Microcavity stability and rigidity are affected by the presence of multiple EPs.

Abstract

Recently, presence of hidden singularities known as exceptional points (EPs) in non-Hermitian quantum systems has opened up a tremendous interest in different domains of physics owing to their unique unconventional physical effects. Effectively for such systems an EP appears as a fascinating topological defect where two mutually interacting eigenstates of the system coalesce. In this work, we report occurrence of EP via avoided crossing between coupled resonance states in an optical microcavity with spatially varying gain loss profile, an optical analogue of non-Hermitian system. With suitably tailored system openness and coupling strength, internally coupled resonances can exhibit EP in a medium with simultaneous presence of loss and gain. We explore the characteristics behaviors of energy eigenvalues in complex energy plane and corresponding eigenstates when the control parameters of the system are adiabatically changed, such a way that they encircle the EP. In this letter, we first ever exploit the above scheme to analyze the optical performance in terms of stability and rigidity of a microcavity simultaneously hosting such multiple EPs.