Nonlinear Pulse Compression to Sub-Two-cycle, 1.3 Mj Pulses at 1.9 Μm Wavelength with 132 W Average Power.

We report the nonlinear pulse compression of a high-power, thulium-doped fiber laser system using a gas-filled hollowcore fiber. The sub-two cycle source delivers 1.3 mJ pulse energy with 80 GW peak power at a central wavelength of 1.87 mu m and an average power of 132 W. This is, so far, to the best of our knowledge, the highest average power of a few-cycle laser source reported in the short-wave infrared region. Given its unique combination of high pulse energy and high average power, this laser source is an excellent driver for nonlinear frequency conversion, toward terahertz, mid-infrared, and soft X-ray spectral regions.