Upconversion luminescence and decay kinetics in a diode-pumped nanocrystalline Nd3+:YVO4 random laser.

Random lasing in nanocrystalline Nd(3+):YVO(4) powder is demonstrated. A method that analyzes the decay kinetics after long-pulse excitation is used to determine the laser characteristics. This method permits to measure the fractional contribution of spontaneous and stimulated emission as well as upconversion as a function of the pump intensity. We observed that maximum linewidth narrowing is achieved when the stimulated emission reaches 50% of fractional contribution in the backscattering cone.