Spatial and temporal instabilities in aCO2laser

We show experimentally the appearance of time-dependent and stationary complex spatial structures in a ${\mathrm{CO}}_2$ laser. A comparison of the data with a theoretical model supports the notion that the observed phenomena result from the nonlinear interaction of transverse cavity modes with the active medium. The simultaneous appearance of spatial and temporal instabilities hints to the interesting prospect that one may be able to study turbulence in a laser system.