Organic random laser generation by stimulated cascaded four-wave mixing

Abstract

Our study investigated the nonlinear lasing properties of a solid-state dye laser. Laser emission was provided by light amplification in static disordered nanostructures with the gain based on a xanthene dye-functionalized epoxy resin polymer. The emission spectrum was found to be reproducible at each near-threshold excitation pulse. We consider that this spectrum results from a non-degenerate cascaded four-wave mixing in the investigated gain medium. The pump beams were generated simultaneously in the bulk isotropic active medium by single-shot excitation on the nanosecond time scale. The downshift and upshift modes were generated via their coherent pump beams. To our knowledge, this type of stimulated highly nondegenerate cascaded four-wave mixing in the visible spectral range (486 nm – 680 nm) has not been experimentally demonstrated before in a random gain medium.