Nonlinear Spectral Singularities and Lasing Threshold Condition

TL;DR

This paper investigates how nonlinear spectral singularities influence the lasing threshold in gain media, deriving explicit intensity expressions and discussing implications for coherent perfect absorption.

Contribution

It introduces a nonlinear generalization of spectral singularities and derives an explicit formula for emitted wave intensity in Kerr nonlinear media.

Findings

Explicit intensity expression for nonlinear lasing threshold

Implications for coherent perfect absorber systems

Extension of spectral singularity theory to nonlinear optics

Abstract

A spectral singularity is a mathematical notion with an intriguing physical realization in terms of certain zero-width resonances. In optics it manifests as lasing at the threshold gain. We explore the application of their recently-developed nonlinear generalization in the study of the effect of a nonlinearity on the lasing threshold condition for an infinite planar slab of gain medium. In particular, for a Kerr nonlinearity, we derive an explicit expression for the intensity of the emitted waves from the slab and discuss the implications of our results for the time-reversed system that acts as a coherent perfect absorber.