Compact laser system delivering 2-\mu m few-cycle pulses for strong-field experiments at 200 kHz repetition rate

Laser pulses in the near-infrared spectral range with a high repetition rate and high pulse energy offer the possibility to perform strong-field experiments such as high-order harmonic generation in gases or strong-field photoemission from the surfaces of nanostructures. Here, we present a compact laser system that delivers ultrashort pulses with a duration of less than 20 fs in the spectral range around 2 $\mu$m and with a pulse energy of up to 30 $\mu$J. The 200-kHz system consists of a commercial turnkey pump laser followed by three home-built frequency conversion/parametric amplification stages. We find an excellent pulse energy stability of 0.19 % measured over 2000 consecutive pulses averaged over 5 minutes for the output pulses of the conceptually simple and passively carrier-envelope phase stable system. An outlook on strong-field experiments performed with the laser system is given.