Sub 100-fs, 5.2-$\mu$m ZGP Parametric Amplifier Driven by a ps Ho:YAG   Chirped Pulse Amplifier and its application to high harmonic generation
  We report a 1 kHz repetition-rate mid-IR (MIR) optical parametric amplifier (OPA) system operating at a central wavelength of 5.2 $\mu$m with the tail-to-tail spectrum extending over 1.5 $\mu$m and delivering 40 $\mu$J pulses that are compressed to 99 fs (5.6 optical cycles). Also we develop a novel pulse compression scheme for further pulse compression and wavelength tunability. As the first application of this laser system, we generated high harmonics in bulk ZnSe above the bandgap, dense exciton generation after 10-photon absorption, high order sum- and difference-frequency generation, ultrafast transition in the conduction band, which reflects the structure of conduction bands. 
Tsuneto Kanai, Pavel Malevich, Sarayoo Sasidharan Kangaparambil,   Heinar Hoogland, Ronald Holzwarth, Audrius Pug\v{z}lys, A...
physics.optics