Nonstationary Regime of Random Lasers

TL;DR

This paper numerically investigates how random lasers transition from stable to unstable regimes with increasing pumping, revealing coherent instabilities like self pulsation linked to cavity leakiness.

Contribution

It introduces a detailed numerical analysis of nonstationary regimes in random lasers, highlighting the role of cavity leakiness in lasing stability and instabilities.

Findings

Stationary lasing becomes unstable above a second threshold.

Coherent instabilities include self pulsation of output intensity.

Leakiness of cavity modes influences the transition to instability.

Abstract

A numerical study is presented of one-dimensional and two-dimensional random lasers as a function of the pumping rate above the threshold for lasing. Depending on the leakiness of the cavity modes, we observe that the stationary lasing regime becomes unstable above a second threshold. Coherent instabilities are observed as self pulsation of the total output intensity, population inversion, and polarization.