High average power GW-level few-cycle pulses at 2 µm wavelength for high photon energy HHG

We present a high average power thulium-fiber CPA system with a record pulse peak power of >1 GW delivering 200 fs pulses in the 2 µm wavelength region. The pulses emitted by this system are spectrally broadened in a hollow-core capillary and subsequently compressed using fused silica, which results in sub-30 fs pulse duration and 140 μJ pulse energy at 50 kHz repetition rate. These characteristics make this source an ideal driver for strong field applications. Current challenges and future perspectives for average power scaling of the laser system as well as the nonlinear compression stage are identified and discussed