146 W, 7 fs, 11 uJ thin-disk oscillator compressed with multiple cells

We report nonlinear broadening and pulse compression in two consecutive multipass cells based on dielectric mirrors. The 120 fs pulses at 14 MHz containing 12.8 μJ were compressed to 7.2 fs with 146 W average power. After the first multipass cell, the driving pulses were compressed to 37 fs. After the second stage, the pulses were compressed to a few-cycle regime with an overall system's throughput of 81%. To our knowledge, this is the highest average power amplification-free few-cycle laser source.