Anomalous Lasing Behavior in a Nonlinear Plasmonic Random Laser

Plasmonic random lasers involve the interaction of emitters and metallic scatterers in extremely small mode volumes, which give rise to interesting nonlinear optical phenomena in random nanocavities. Here, we present an anomalous lasing behavior in a plasmonic random laser composed of vertically standing ZnO nanorods decorated with Au nanoislands and infiltrated with a dye-doped polymer matrix. The coupling of random laser modes to plasmonic nanocavities with high absorption losses results in unusual lasing behavior. At higher pump fluences, the nonlinear optical behavior of the Au nanoislands induces a second kink in the threshold characteristics. Various statistical tools have been employed to analyze the intensity fluctuations of the random laser modes, validating this unique lasing behavior.