Photon statistics of laserlike emission from polymeric scattering gain media

The coherent properties of the temporally and spectrally narrowed emission of laser-induced fluorescence of organic dyes hosted inside artificial scat tering matrices (random lasers) were investigated. The excitation source wa s a frequency-doubled 200-fs pulsed laser emitting at 400 nm. Spectral and temporal features were simultaneously recorded with a spectrograph and a st reak camera operating in photon-counting mode. Photon-number distributions were thus created. The temporal coherence of the laserlike emission above a nd below the excitation energy threshold was investigated from the photon-n umber distribution that was obtained. (C) 2000 Optical Society of America. OCIS codes: 030.5290, 030.5260, 170.6510, 170.6280.