Generation of few-cycle millijoule pulses at 5 μm employing a ZnGeP2-based OPCPA pumped with GW peak power pulses at 2 μm

Abstract

A mid-infrared optical parametric chirped pulse amplification (OPCPA) system generating few-cycle pulses with multi-GW peak power at a 1 kHz repetition rate is presented. The system is pumped by a high-energy 2-μm picosecond source to exploit the high nonlinearity of ZnGeP2 (ZGP) crystals for parametric amplification. Employing a dispersion management scheme based on bulk materials and a spatial light modulator pulses as short as 75 fs are obtained in the idler at a center wavelength of 5 μm. The maximum generated pulse energy of 1.2 mJ translates into a peak power of 14 GW. Moreover, damage considerations of ZGP crystals at high 2 μm pump pulse intensities in the few-ten picosecond range are explored.