Nonlinear pulse compression to 51-W average power GW-class 35-fs pulses at 2-µm wavelength in a gas-filled multi-pass cell
Philipp Gierschke, Christian Grebing, M. Abdelaal, Mathias Lenski, Joachim Buldt, Z. Wang, Tobias Heuermann, M. Mueller, Martin Gebhardt, Jan Rothhardt, Jens Limpert
Abstract
We report on the generation of GW-class peak power, 35-fs pulses at 2-µm wavelength with an average power of 51 W at 300-kHz repetition rate. A compact, krypton-filled Herriott-type cavity employing metallic mirrors is used for spectral broadening. This multi-pass compression stage enables the efficient post compression of the pulses emitted by an ultrafast coherently combined thulium-doped fiber laser system. The presented results demonstrate an excellent preservation of the input beam quality in combination with a power transmission as high as 80%. These results show that multi-pass cell based post-compression is an attractive alternative to nonlinear spectral broadening in fibers, which is commonly employed for thulium-doped and other mid-infrared ultrafast laser systems. Particularly, the average power scalability and the potential to achieve few-cycle pulse durations make this scheme highly attractive.