Random laser tailored by directional stimulated emission

摘要

The spectrum of a random laser (RL) may appear either as a set of sharp resonances or as a smooth linensuperimposed on the fluorescence. Recently, Leonetti, Conti, and Lopez [Nat. Photonics 5, 615 (2011)] accountednfor this duality with the onset of a mode-locked regime that is triggered by the increase of both the number ofnactivated modes and of the intermode interaction and is accompanied by a pulse shortening. Here we report annextensive review of the experimental approach used by Leonetti et al., including the sample preparation and thenparticulars of the setup. Here we describe also the way in which our approach allows us either to set the degree ofninteraction between modes or to have a certain degree of control over the effective set of resonances brought tonlasing. Moreover we report an investigation on the spatial properties of the RL which brings further confirmationnof the synchronization picture, whose physical origin is deepened.