Spontaneous Formation and Switching of Optical Patterns in Semiconductor Microcavities

We study spontaneous pattern formation and symmetry breaking in broad area and pre-patterned (spatially modulated) semiconductor microcavities under lasing conditions. In broad area VCSELs, we observe the spontaneous formation of regular arrays consisting of charge “±1” optical vortices. The formation of these patterns stems from transverse mode locking of almost wavelength degenerated Gauss-Laguerre (GL) modes. The observed patterns in Gain modulated broad area VCSELs and their dynamical behavior depends dramatically on the modulation strength. In ring shaped VCSELs lasers we observe necklace-like pattern formation and switching as a function of the injection current. The formation of the patterns and, in particular, their switching is shown to stem from stability loss of the lasing pattern to perturbations of more complex pattern which, in turn, is stable under similar pumping conditions. Having the advantage of a strong, saturating nonlinear response with an inherent loss compensation mechanism, such lasers are potentially the best microlabortories for studying nonlinear phenomena and for the generation and employment of complex optical fields. Applications can be found in optical data storage, information distribution and processing, laser cooling and more.