Tunable degree of localization in random lasers with controlled interaction

TL;DR

This paper demonstrates that the degree of mode localization in a random laser can be precisely tuned by controlling the pump laser spot, affecting the interaction between modes and their spatial properties.

Contribution

It introduces a method to control the localization of random laser modes by shaping the pump laser, revealing the relationship between mode interaction and localization.

Findings

Localized modes dominate in low interaction regimes

Extended modes emerge in high interaction regimes

Localization can be tuned at the micrometer scale

Abstract

We show that the degree of localization for the modes of a random laser (RL) is affected by the inter mode interaction that is controlled by shaping the spot of the pump laser. By experimentally investigating the spatial properties of the lasing emission we infer that strongly localized modes are activated in the low interacting regime while in the strongly interacting one extended modes are found lasing. Thus we demonstrate that the degree o localization may be finely tuned at the micrometer level.