Generation of high repetition rate far-infrared laser pulses

We report the generation of pulsed optically pumped far-infrared (FIR) radiation with a repetition rate of 200 kHz. These pulses were obtained in a straightforward method by pumping a FIR resonator with a high repetition rate, rf-excited, waveguide CO2 laser. Pulses approximately 50 ns wide were generated both at 432.6 m in HCOOH, and 117.7 +n in CH,F,. The pulse width of the FIR radiation was studied as a function of the CO2 pulse width, and the relative delay between the two was measured. Based on this data we conclude that the FIR radiation was gain switched and of a duration which was a function of either the gain bandwidth of the FIR transition, or more likely the FIR cavity parameters.