High-efficiency bismuth borate-based optical parametric chirped pulse amplifier with approximately 2.1 mJ, 38 fs output pulses at approximately 2150 nm

Abstract

We present a compact and cost-effective mJ-level femtosecond laser system operating at a center wavelength of ~2.15 µm. An affordable two-stage Yb:YAG chirped pulse amplifier provides >10 mJ, ~1.2 ps pulses at 1030 nm to pump 3-stage OPCPA based on BiBO crystals and to drive the supercontinuum seed in the YAG crystal. The energy of amplified pulses in the wavelength range of 1.95 -2.4 µm reached 2.25 mJ with a pump-tosignal conversion efficiency of ~25% in the last OPCPA stage. These pulses were compressed to 38 fs in a pair of Suprasil 300 glass prisms.