Radiation generation by an ionization front in a gas-filled capacitor array

Summary form only given, as follows. A new radiation source, in which the static electric field of an alternatively biased capacitor array is directly converted into coherent radiation by a laser produced ionization front (i.e., a moving vacuum/plasma boundary), is investigated experimentally. The frequency of the radiation is approximately given by /spl omega//sub p//sup 2//2k/sub 0/c, where k/sub 0/=/spl pi//d is the wavenumber defined by the distance d between the capacitors. Its electric field is approximately equal to that of the capacitor field E/sub 0/. The device can potentially produce coherent pulses of high power (MW), tunable radiation in different frequency regimes (microwave, THz, ...). In a proof-of-principle experiment, short (<5 ns) microwave pulses with tunable frequency scaling linearly with the plasma density were generated between 6 and 21 GHz. These results, as well as results obtained with other structures: Ka-band waveguide and coaxial line in the microwave range, and a /spl mu/-structure in the 10 /spl mu/m range, will be presented.