Spontaneous pulsing, period doubling, and quasi-periodicity in a unidirectional, single-mode, inhomogeneously broadened ring laser

Studies of a unidirectional ring laser using the 3.51-..mu..m transition in xenon reveal a well-defined second threshold above the threshold for cw lasing at which spontaneous self-pulsing is observed. Higher excitation thresholds are found for transitions through a sequence of period doublings or to quasi-peridoic behavior (two independent pulsing frequencies). Detuning the laser cavity from resonance does not lead to the dramatic complications in the pulsing structure that were observed in Fabry-Perot lasers. Instead, with increasing detuning we find a smooth reduction in complexity of the dynamical behavior that seems to correspond principally to the reduction in the gain and the laser intensity with detuning. We also find some evidence that transverse beam profiles cause qualitative and quantitative changes in the location and nature of the various transitions.