Two-photon pumped random lasing in a dye-doped silica gel powder

We report the first observation of two-photon pumped random laser action in the ground powder of a silica gel containing rhodamine 6G doped silica nanoparticles. When this solid-state dye system is pumped with 800 nm femtosecond-lasing pulses, random laser-like effects such as spectral narrowing and temporal shortening are observed with a laser-like emission peak centered around 598 nm. A comparison between the emission features, random laser behavior and threshold of random laser action, following one- and two-photon excitations is also performed.