Self-pulsing dynamics of an optically-pumped CH/sub 3/OH 119-/spl mu/m ring laser

Self-pulsing dynamics of an optically-pumped CH/sub 3/OH 119 /spl mu/m ring laser have been observed for backward emission. As the far infrared cavity frequency was tuned close to the crossover of backward and forward output, period one pulsing at a frequency around 2.1 MHz was followed by modulated pulsing due to suppressed forward emission. The ring laser emitted self-pulsing output at around 0.1 MHz with its higher order harmonics under increased operation pressures. A three-level model interacting with a pump and counterpropagating far infrared radiation fields is described to explain the observation.