Antisymmetric chirp transfer to high-energy ultraviolet pulses via gas-based chirped four-wave mixing
Spectro-temporal shaping of high-power femtosecond ultraviolet (UV) pulses remains a key challenge in ultrafast optics. Tailoring high-energy, ultrashort UV pulses underpins applications in ultrafast dynamics, high-precision spectroscopy, strong-field physics, charged-particle radiation sources, and industrial microfabrication. However, the transmission and damage threshold of the dielectric optics limit programmable shaping for high-power UV pulses. Towards overcoming this challenge, we demonstrate an antisymmetric dispersion transfer from near-infrared (NIR) pulses to UV pulses via chirped four-wave mixing (CFWM) in noble gas, whereby negatively chirped NIR pulses map quasi-linearly to positively chirped UV in a gas-filled hollow capillary fiber (HCF) at the expense of a moderate conversion efficiency of 13%. This antisymmetric chirp transfer approach broadens the basis for tailoring UV pulses by leveraging the high damage tolerance, large bandwidth acceptance, and intrinsically low dispersion of noble gases, rather than relying on conventional nonlinear crystals.