Determining random lasing action

Random lasing - for which disorder is exploited to enhance stimulated emission - has emerged as a paradigmatic phenomenon of complex lasers. Random lasers feature unique properties such as tunable coherence and reconfigurable spectral emission. Nevertheless, their complexity sets them apart from conventional lasers, making it challenging to determine whether random lasing is occurring. In this Expert Recommendation, I discuss experimental methods required to properly assess and demonstrate random lasing action. Random lasing, which exploits disorder to enhance stimulated emission, challenges the conventional descriptions of lasing. This Expert Recommendation describes experimental methods required to properly assess and demonstrate random lasing action.