Parametric chirp and 20-fold compression of pulses from a quasi-cw picosecond optical parametric oscillator

A linear chirp was observed for phase-conjugate picosecond pulses from a resonator-type optical parametric oscillator based on an LiNbO₃ crystal pumped by the second harmonic of a YAG:Nd³⁺ laser with active mode locking and Q switching at repetition frequencies up to 10 kHz. A 20-fold compression of the parametric oscillator pulses to 2.5 psec was achieved.