Few-cycle short-wave-infrared light source for strong-field experiments at 200 kHz repetition rate.

We present a compact, few-cycle, short-wave infrared light source delivering 13 µJ, carrier-envelope phase (CEP) stable pulses around 2 µm, operating at 200 kHz repetition rate. Starting from an ytterbium fiber amplifier, the seed is produced via white-light generation followed by difference frequency generation, and later amplified in two BiBO nonlinear crystals. A pulse duration of 15.8 fs is measured with the dispersion scan technique, while the CEP stability is assessed via a monolithic spectral interferometry scheme. We demonstrate the potential of the system to drive strong-field experiments by performing high-order harmonic generation in argon gas.

Multi-gigawatt peak power post-compression in a bulk multi-pass cell at a high repetition rate.

The output of a 200kHz, 34W, 300fs ytterbium amplifier is compressed to 31fs with >88% efficiency to reach a peak power of 2.5GW, which to date is a record for a single-stage bulk multi-pass cell. Despite operation 80 times above the critical power for self-focusing in bulk material, the setup demonstrates excellent preservation of the input beam quality. Extensive beam and pulse characterizations are performed to show that the compressed pulses are promising drivers for high harmonic generation and nonlinear optics in gases or solids.

Postcompression of picosecond pulses into the few-cycle regime.

In this work, we demonstrate postcompression of 1.2 ps laser pulses to 13 fs via gas-based multipass spectral broadening. Our results yield a single-stage compression factor of about 40 at 200 W in-burst average power and a total compression factor >90 at reduced power. The employed scheme represents a route toward compact few-cycle sources driven by industrial-grade Yb:YAG lasers at high average power.