Control of random lasing in ZnO/Al2O3 nanopowders

We demonstrate that the random lasing wavelength of ZnO/Al2O3 nanopowders can be controlled by varying the weight fraction of Al2O3. This controllability is due to the fact that the extent of self-absorption by ZnO nanopowder can be modified by changing the photon-transport mean free path. The lasing threshold excitation power is also dependent on the weight fraction of Al2O3. The random lasing characteristic can be explained well by a theoretical model based on the photon-transport mean free path. (C) 2011 American Institute of Physics. [doi:10.1063/1.3665913]