Random laser properties of Nd crystal powders.

This work presents an overview of near infrared random lasing emitters based on a variety of neodymium (Nd)-doped crystal powders with different Nd concentrations and different grain sizes. The pump-configuration used allows for an absolute measurement of both pumping and emitted energies. The results provide an absolute measure of the random laser efficiency and prove a relation of direct proportionality between the absorbance of the material and the laser slope efficiency. Likewise, they suggest a relationship close to an inverse proportionality between the absorbance and the threshold energy per unit area. The temporal behavior of the random laser emission shows noteworthy differences between local and spatially integrated registers.