Sub-50 Fs Self-Compression of 5-μm Pulses in a Hollow-Core Fiber

High-energy few-cycle pulses in the mid-IR are important for applications in strong-field physics. A popular method to generate such pulses is spectral broadening of ultrashort pulses by means of self-phase modulation (SPM) in a nonlinear medium with subsequent post-compression. This is an established technique in the near infrared by employing hollow-core fibers (HCF) [1], thin plates or multi-pass cells, but there are no studies for wavelengths longer than 4 μm. Here, we report self-compression of pulses at 5-μm wavelength in a HCF due to solitonic effects. A numerical model is established for the pulse propagation and is benchmarked against the experimental results.