Highly efficient optical parametric amplifier tunable from near- to mid-IR for driving extreme nonlinear optics in solids.

We have developed a robust optical parametric amplifier (OPA) based on three-AgGaS2 -crystal pumping by a Cr:Forsterite GW femtosecond laser system, generating 150 fs pulses in dual bands of 1.6-2.0 μm (signal wave) and 3.5-5.5 μm (idler wave). By introducing a negative prechirp to the pump, a combined efficiency in two waves of greater than 10% was achieved, with signal energy up to 110 μJ and idler energy up to 43 μJ. Operation parameters of the system (intensity up to 90  TW/cm2 ) make OPA a promising tool for driving nonlinear optical phenomena, including generation of optical harmonics and laser-induced extreme states of matter in solids and liquids. As a proof of principle, we generated harmonics up to the sixth order and sum frequencies in 5 mm thick polycrystalline ZnSe.