TIME-RESOLVED STUDIES OF STIMULATED-EMISSION FROM COLLOIDAL DYE SOLUTIONS

The temporal profiles of the omission from titania particle suspension s in Rhodamine 640 perchlorate dye solutions excited by 10-ps pulses o f 527-nm radiation were measured over a wide range of particle and dye concentrations and laser powers. The dynamics of stimulated emission from random media is modeled by a random walk of photons within the co lloid and rate equations for molecular excitations. The pulse width an d the dependence of the threshold for laser action on dye and scatter concentration are computed by a Monte Carlo simulation of the model an d are found to be in qualitative agreement with experiment. (C) 1996 O ptical Society of America