1209.4552 (Regine Frank)

Transport theory: Spatial coherence of random laser emission    [PDF]

Regine Frank

Recently random laser reached the stage of technologi- cal applicability. They have already been engineered as coherent microscope light sources in combination with light transport based disordered lenses. The big issue for all kinds of applications is the degree of coherence of the emitted radiation. The lasing spot sizes in dif- ferent regimes may provide different degrees of spatial and temporal coherence and as a consequence they can be perfectly tunable light sources for the case that the modal behavior can be controlled easily. In this letter we investigate the spatial coherence lengths of different random laser samples theoretically. The samples only vary in their filling with spherical ZnO Mie scatterers. Beyond we show, that the scattering mean free paths of random lasers are not only a material characteristics and dependent to the filling, instead the mean free paths change in depth of the sample and therefor depend on the nonlinear self-consistent gain of the random lasing principle.

View original: http://arxiv.org/abs/1209.4552