Transition to lasing induced by resonant absorption

TL;DR

This paper theoretically shows that increasing absorption in laser systems with constant gain can induce lasing by creating new modes, a phenomenon called absorption induced lasing (AIL), demonstrated in various optical systems.

Contribution

The paper introduces and explains the universal phenomenon of absorption induced lasing (AIL), showing its occurrence in simple and nano-scale laser systems.

Findings

Absorption increase can trigger lasing without gain change.

New lasing modes emerge due to narrow linewidth absorption.

The effect is robust against frequency detuning.

Abstract

We theoretically demonstrate that increase of absorption with constant gain in laser systems can lead to onset of laser generation. This counter-intuitive absorption induced lasing (AIL) is explained by emergence of additional lasing modes created by an introduction of an absorbing medium with narrow linewidth. We show that this effect is universal and can be encountered in simple Fabry-Perot-like systems and doped spherical dielectric nanoresonators. The predicted behavior is robust against frequency detuning between the gain and absorbing medium.