Broadly tunable femtosecond pulses generated by optical parametric oscillation

A singly resonant optical parametric oscillator is demonstrated that uses a beta-barium borate crystal and is synchronously pumped by microsecond pulse trains of a Nd:glass laser (0.8 psec, 527 nm). Broadly tunable pulses are generated in the wavelength range 0.7-1.8 microm with a duration of 160-260 fsec and an energy conversion of 3%. Steep pulse wings are observed, with a 1/e decay time of approximately 90 fsec. Under special conditions, parametric pulses as short as 65 +/- 7 fsec are obtained.