Modal interference and dynamical instability in a solid-state slice laser with asymmetric end-pumping

We observed complicated emission patterns consisting of different transverse modes and associated intensity pulsations at beat frequencies between pairs of transverse eigenmodes in a solid-state thin-slice Fabry-Perot laser with asymmetric end-pumping. The dependence of transverse patterns and pulsation frequencies on pump power has been demonstrated. The interference among nonorthogonal transverse eigenmodes, which are formed in a deformed Fabry-Perot microcavity possessing an asymmetric, gradient refractive-index potential for optical waves, is proposed for explaining observed instabilities. Intensity modulations have been remarkably reproduced by numerical simulations of model equations.