We investigate the generation of superradiant far-infrared 496-mu-m CH3F pulses and produce for the first time smooth and reproducible 373-mu-m CH3CN superradiant pulses by pumping with pulses from a hybrid 10-mu-m CO2 laser truncated within almost-equal-to 10 ps by a plasma shutter of new design. Superradiance is confirmed by measurement of the pressure dependence of the intensity, the width and the delay versus the pump pulse. We observe pulse durations considerably under the limit or the inverse linewidth of the transition. Thus, we demonstrate for the first time that rapid truncation of the pump pulse is essential for reducing pulse duration of superradiant far-infrared emissions.
