Effects of spatial nonuniformity of cavity dielectric constant on lasing dynamics

摘要

Recent observation of two-mode lasing in random lasers is discussed in the context of the problem of distinguishing between lasing with coherent and non-coherent feedback. A general semiclassical theory of lasing in cavities with a spatially non-uniform dielectric constant is developed. It is shown that the non-uniformity causes a radiative coupling between modes of the empty cavity, which results in a renormalization of the coefficients responsible for non-linear interaction between lasing modes. One of the consequences of this renormalization is the enhancement of the effects of spatial hole burning and promotion of the multi-mode lasing.