Active subnanometer spectral control of a random laser

TL;DR

This paper presents an experimental method to precisely control the emission spectrum of a micro random laser, enabling selection of individual modes with sub-nanometer resolution through pump beam profile optimization.

Contribution

It introduces a novel optimization protocol for the pump beam profile to achieve spectral control and mode selection in micro random lasers.

Findings

Successful mode selection with sub-nanometer precision

Enhanced emission at targeted wavelengths

Suppression of unwanted modes

Abstract

We demonstrate an experimental technique that allows to achieve a robust control on the emission spectrum of a micro random laser and to select individual modes with sub-nanometer resolution. The presented approach relies on an optimization protocol of the spatial profile of the pump beam. Here we demonstrate not only the possibility to increase the emission at a wavelength, but also that we can isolate an individual peak suppressing unwanted contributions form other modes.