Cavity controlled spectral singularity

TL;DR

This paper theoretically investigates a PT-symmetric ring cavity with saturable gain and loss, demonstrating control over spectral singularities through cavity and atomic parameters, and exploring regularization and growth limitations.

Contribution

It introduces a model for controlling spectral singularities in PT-symmetric systems via cavity and atomic detuning parameters, extending understanding of optical bistability.

Findings

Spectral singularities can be fully controlled by cavity and atomic detuning.

Detuning regularizes the singularity in the linear regime.

Higher input power limits infinite growth in undetuned systems.

Abstract

We study theoretically a PT-symmetric saturable balanced gain-loss system in a ring cavity configuration. The saturable gain and loss are modeled by two-level medium with or without population inversion. We show that the specifics of the spectral singularity can be fully controlled by the cavity and the atomic detuning parameters. The theory is based on the mean-field approximation as in standard theory of optical bistability. Further, in the linear regime we demonstrate the regularization of the singularity in detuned systems, while larger input power levels are shown to be adequate to limit the infinite growth in absence of detuning