Experimental observation of instabilities and chaos in the secondary-beat frequency of a multiple-transverse-mode CO2laser

Abstract
A cw CO2 laser with a predominantly homogeneously broadened lasing transition is shown to lose its stability under certain values of cavity detuning when more than two transverse modes are excited. The instability dynamics is found to be strongly dependent on the excited modes. In particular, we have observed period-doubling bifurcations, f3 followed by f5 periodic windows, and a frequency locking of two fundamentals at some rational ratio.