Abstract

Ultrafast thin-disk lasers (TDLs) have consistently been at the forefront of progress in the performance of ultrafast laser sources in the last decades. Modelocked TDLs are particularly attractive for applications calling for high (MHz) repetition rates and high pulse energy, from a compact one-box oscillator. Average powers of several hundreds of watts and pulse energies approaching 100 μJ have been demonstrated [1], surpassing any other modelocked oscillator technology. However, their long pulse duration remains a problem for many applications, and pulse durations ≪100 fs remain undemonstrated with average powers of >20 W. An alternative approach is to use external pulse compression. Previously, high-throughput (>60%) external pulse compressors have been demonstrated based on (1) gas-filled Kagome-type fibers where P_peak=105 MW (at P_avg=46 W) have been achieved, but with a pulse-width Δt =108 fs [2], and (2) multi-pass cells, where P_peak=67 MW with P_avg=75 W, Δt=40 fs [3], and 60 MW peak power with P_avg=60 W, Δt=16 fs have been demonstrated [4]. Here, we compress our 13.4 MHz, 123 W(9μJ), 534 fs (P_peak =15.7 MW) thin-disk oscillator down to 27 fs at 98 W average power, reaching 166 MW of peak power at 80% overall efficiency, which is to the best of our knowledge, the highest peak power amplifier-free source so far demonstrated.

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