Application of External Electric Field on Laser Filaments for Ultrafast Mid-Infrared Sub-Cycle Pulse Stabilization

The stability of light sources in imaging and spectroscopy systems is a significant parameter for obtaining high quality and highly precise images and spectra. In our previous work [1], we used ultrafast mid-infrared (MIR) sub-cycle pulses to serve as the light source for simultaneous chemical imaging and spectroscopy. These sub-cycle pulses were generated by laser filamentation, and the pulses were sufficiently broadband and intense to generate MIR hyperspectral images. However, jitters in the order of milliseconds are inherent in filamentation operating in the kilohertz range [2], requiring the utilization of techniques such as multiple image-averaging to minimize their detrimental effects. These jitters are caused by self-heating brought about by the recombination of the plasma generated by the filamentation process. Liu et al. [2] in their recent work utilized the application of a strong electric field onto the filament to suppress these plasma recombinations. Based on their results, the stability of the filament and the resulting supercontinuum light source greatly improved.