Frozen wave generation of bandwidth-tunable two-cycle THz radiation

We report on the application of a photoconductive frozen wave generator (FW G) for the generation of 0.36-THz radiation. Through the excitation of a bi polar photoconductive array, a two-cycle THz electrical transient is create d. The THz electrical transient occurs on a time scale much shorter than th e carrier lifetime in the semiconductor. Furthermore, variations in the uni formity of the optical excitation intensity across the photoconductive arra y introduce a controlled THz temporal chirp, thus providing for fine bandwi dth tunability of the device. Modeling of the FWG is successful in describi ng both the time variation and the amplitude spectrum of the photogenerated THz radiation. (C) 2000 Optical Society of America [S0740-3224(00)00108-9] OCIS codes: 320.7080, 320.5390, 320.7160, 130.5990.