Optical parametric generation of femtosecond pulses up to 9 μm with LiInS2 pumped at 800 nm

We demonstrate direct access to the 4.8–9 μm spectral region with 800 nm, 1 kHz pumping of a femtosecond optical parametric amplifier based on the wide-gap wurtzite-type LiInS2. LiInS2 did not exhibit two-photon absorption at 800 nm and seems applicable at this pump wavelength with intensities of the order of 100 GW/cm2 for down-conversion of high energy ultrashort pulses up to its mid-IR edge at ≈12 μm.