GENERATION OF ULTRASHORT, DISCRETE SPECTRUM MICROWAVE PULSES USING THE DC TO AC RADIATION CONVERTER

The output radiation of a de to ac radiation converter is characterize d. A relativistic ionization front passing through a capacitor array o f period d=1 cm produces short pulses of tunable radiation between 39 and 84 GHz with a gas pressure between 0 and 30 mT. The frequency spec tra of the produced pulses are discrete and exhibit full widths at hal f maximum between 12% and 28%, consistent with the expected width for six cycles' pulses. An upper bound of 750 ps (detection bandwidth limi ted) is placed on the pulse widths. These are the shortest pulses prod uced by a source of coherent radiation in this frequency range. (C) 19 98 American Institute of Physics.