Optical parametric amplification in a random medium: BBO nanopowder

The emission and propagation of light in disordered media has always been a topic of interest in science, mainly because in nature this is the most common way of light emission and propagation. This research topic received a particular attention after the report of the first highly efficient random laser (RL) [1]. Indeed a large number of investigations discussing the fundamentals and the applications of RL's have been developed in the past decade. Among the motivations for such studies, we mention the RL simplicity and the low spatial coherence associated to its emission, which are indispensable requirements, for instance, on speckle-free full field imaging [2]. Here we present a new low-spatial-coherence-laser-based source, the random optical parametric emitter (ROPE) in a nanopowder consisting of s-BaB2O 4 (s-BBO) 10-nm-nanocrystals.