Abstract

Generation of cw femtosecond tunable pulse trains by optical parametric oscillators (OPOs) has recently become a well-established technique owing to emergence of reliable and powerful solid-state pump lasers and new nonlinear crystals. However, numerous applications require a single, powerful tunable pulse. An alternative to the OPO approach that relies on traveling-wave parametric amplification has been known from the very beginning of application of ultrashort-pulse parametric convectors. This alternative approach has been extended to the femtosecond range by using a dye-laser pump.¹ However, its coherence properties had to be improved. Our research has shown that by cascading parametric-amplifier (PA) stages and choosing proper pump geometry one can obtain laser-quality beams from a traveling wave device. The arrangement we used consisted of three PA stages: the seeder, driven at high gain in order to produce parametric superfluorescence; the preamplifier, which, along with amplification, performed spatial filtering; and the power amplifier.

© 1994 Optical Society of America