Efficient generation of tunable subpicosecond pulses in the infrared

A novel parametric generator-amplifier system is discussed which for the first time allows the generation of tunable pulses in the infrared with substantial pulse shortening and with high energy conversion of up to 20%. Starting with an intense laser pulse of a mode-locked Nd: glass laser system of ≈ 8 ps, a signal pulse at ≈ 6500 cm^-1 is produced by a single path parametric generator. This signal pulse is subsequently amplified generating an intense idler pulse in the IR. Varying the time delay between the signal and pump pulse in the amplifier stage, the pulse duration of signal and idler is readily adjusted. The shortest pulses are nearly bandwidth limited of duration 0.5 ps with energy conversion exceeding 5% in the frequency range around 6500 cm^-1.