We generated synchronized sub-200-fs pulses between 3 and 4.4 mm at a 1-kHz repetition rate by pumping a KNbO3 optical parametric amplifier with a femtosecond Ti:sapphire regenerative amplifier and seeding it by narrow-band quasi-cw radiation. Output idler energies as high as 7 µJ at 4 µm are reported from this extremely simple single-stage device, which correspond to amplification factors as high as 3 × 105 and a conversion efficiency of 15.
© 1996 Optical Society of America
V. Petrov and F. Noack, "Mid-infrared femtosecond optical parametric amplification in potassium niobate," Opt. Lett. 21, 1576-1578 (1996)