Observation of instabilities and chaos in optically pumped far-infrared lasers

A short discussion of the properties of far-infrared (FIR) lasers shows that these are suitable systems to observe instabilities and chaos. Experiments on (N-15)H3 FIR waveguide lasers show a single-mode self-pulsing instability and period doubling. A CH2F2 Fabry-Perot resonator laser shows the same single-mode self-pulsing, period-doubling, and chaotic emission. The experiments are done at relatively high pressure, at which inhomogeneous broadening can occur only through the ac-Stark effect. Qualitatively, the observations agree with theoretical model calculations.