High-repetition-rate optical parametric chirped-pulse amplifier producing 1-µJ, sub-100-fs pulses in the mid-infrared

We present a high-repetition-rate, femtosecond optical parametric chirped pulse amplifier (OPCPA). Its seed signal is obtained by difference frequency generation from the two-branch output of a commercially available Er:fiber laser amplifier. The optical parametric amplifier is pumped by a commercially available diode-pumped solid-state laser. In a two-stage amplification setup we have achieved a gain of 100'000, resulting in approximately 1 microJ femtosecond mid-infrared pulses in the wavelength range between 3 and 4 microm and an amplification bandwidth of >300 nm at a repetition rate of 100 kHz. The pulses have been compressed to 92 fs by a 4-prism compressor.