Two-mode emission and polarization dynamics at lasing threshold in a vertical-cavity surface-emitting laser

Summary form only given. VCSELs are well known to show polarization instabilities or polarization switching (PS) if the current is changed as well as fluctuations of their state of polarization at fixed current. Nevertheless, in most devices only one of two possible orthogonal linear polarized fundamental transverse modes, which are frequency split by birefringence, is emitted at the threshold to laser emission. In this contribution, we present the results of experimental investigations on the situation when both of the fundamental transverse modes are excited at threshold.