Inherent Stochastic Linearization of Random Laser Modes

TL;DR

This paper demonstrates that inherent noise in weakly scattering random lasers causes a linearization of lasing modes, affecting mode competition and potentially enabling control over multimode lasing behavior.

Contribution

It reveals how noise induces linearization of modes in random lasers, a novel insight into the interplay between noise and nonlinear mode interactions.

Findings

Noise generates emission below threshold

Noise restrains nonlinear mode competition

Mode linearization depends on gain medium noise properties

Abstract

Weakly scattering random lasers exhibit lasing modes that spatially overlap and can interact strongly via gain saturation. Consequently, lasing in high-threshold modes may be suppressed by strong low-threshold lasing modes. We numerically examine the effect of inherent noise on this strong nonlinear phenomenon. Noise generates emission below the lasing threshold and restrains the dramatic nonlinear behavior above threshold. The result is a linearization of random laser modes and is possible when noise overcomes spatial hole burning. Results suggest that control over the noise properties of the gain medium may facilitate or inhibit certain modes to lase in the multimode regime.