Supercontinuum-seeded, carrier-envelope phase-stable, 4.5-W, 3.8-μm, 6-cycle, KTA optical parametric amplifier driven by a 1.4-ps Yb:YAG thin-disk amplifier for nonperturbative spectroscopy in solids

We demonstrate a carrier-envelope phase (CEP)-stable, KTA (KTiOAsO4)-based optical parametric amplifier (OPA) delivering 6-cycle (79 fs), 3.8-mu m pulses at a 100-kHz repetition rate with an average power of 4.5 W. The pivotal achievement is the stable generation of supercontinuum (SC) seed pulses in YAG with 1.4-ps pulses, which are the longest for SC generation on its longer wavelength side to 2.2 mu m. This technology offers a robust and simplified OPA architecture with characteristics of passively stabilized CEPs, simplified dispersion management with bulk materials, wavelength tunability for 1.3-4.5 mu m for spectroscopy, and a proof of concept on its power scaling with kilowatt-class pump lasers. The total output power of 17 W(signal plus idler) is achieved, and this high photon flux opens novel statistics-driven spectroscopy for rare events in strong-field physics. (C) 2019 Optical Society of America