Parametric generation of 1-ps pulses between 5 and 11 /spl mu/m with a ZnGeP/sub 2/ crystal

We use a novel picosecond source (a seeded optical parametric amplifier tunable near 3 /spl mu/m) to pump a type-11 ZnGeP/sub 2/ traveling-wave optical parametric generator, With a rather simplified two-pass arrangement, the tunability of the driving Ti:sapphire regenerative amplifier is extended continuously up to 11 /spl mu/m. As a result of the short pulse pumping and the pulse compression accompanying the parametric amplification, nearly bandwidth-limited pulses could be generated for the first time with this crystal. We report microjoule output energies with 20% quantum efficiency and unprecedentedly low (<100 MW/cm/sup 2/ for a crystal length of only 1 cm) parametric gain thresholds.