Hollow-core-waveguide compression of multi-millijoule CEP-stable 3.2 μm pulses

We present the extension of high-power pulse compression deeper into the challenging IR spectral range around 3.2 mu m wavelength, where the effects of material absorption, dispersion, and free electron disturbance on nonlinear propagation become increasingly limiting parameters. 5 mJ, 80 fs pulses from a KTA parametric amplifier were spectrally broadened in a large-core hollow fiber with argon as the nonlinear medium. Subsequent compression through anomalous dispersion in CaF2 yielded 2.5 mJ close-to-transform-limited two-cycle pulses exhibiting a passively stabilized carrier envelope phase (CEP). Furthermore, we outline the feasibility of generating sub-two-cycle pulses with good spatial and temporal characteristics. (C) 2016 Optical Society of America