Gigawatt few-cycle mid-IR pulses generated from advanced non-oxide nonlinear crystals

Advanced nonlinear materials - LiGaS2 (LGS), $\mathrm{HgGa}_{2} \mathrm{~S}_{4}$ (HGS) and BaGa2 GeS6 (BGGS) - were studied for parametric down conversion of Cr:Forsterite laser pulses into 1.5 $-8 \mu \mathrm{m}$ spectral region. Total conversion efficiency as high as $18 \%$ was achieved in HGS based OPA resulting in 0.4 - 2.4-gigawatt 80 fs pulses. Using LGS, broadband mid-IR pulses with energy up to $20 \mu \mathrm{J}$ were obtained. After bulk compression in a Ge plate, a pulse duration as low as 60 fs was measured, corresponding to three optical cycles of $5.9 \mu \mathrm{m}$ carrier wavelength. New non-oxide BGGS crystal was compared with HGS, showing great potential for efficient parametric amplification in mid-IR. The developed source provides numerous opportunities for time-resolved pump-probe experiments and opens access to attosecond physics and material sciences.