Ultrabroadband supercontinuum generation through filamentation in a lead fluoride crystal

We report the filamentation and supercontinuum generation of a femtosecond pulse in a piece of bulk lead fluoride (PbF2) crystal with a high bandgap and an ultrabroadband frequency window covering 5.6 octaves. A broadband supercontinuum spanning 4.7 octaves from 350 to 9000 nm is demonstrated. The filament traces and bright conical visible emission patterns of the supercontinuums are observed. Additionally, simulations are performed to investigate the supercontinuum generation in the PbF2 crystal by using a waveguide model that considers the supercontinuum generated in the filamentation as a process of pulse propagation in waveguides written by filamentation. The findings of this study demonstrated that a PbF2 crystal is a very suitable nonlinear medium for use in supercontinuum generation by filamentation. This is of significance for the development of ultrabroadband supercontinuum sources based on bulk media and high-peak-power lasers.