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 window and damage threshold of dielectric optics limit programmable shaping of high-power UV pulses. To overcome this challenge, we demonstrate an antisymmetric chirp transfer from near-infrared (NIR) pulses to UV pulses via chirped four-wave mixing (CFWM) in a noble gas, whereby negatively chirped NIR pulses map quasi-linearly to positively chirped UV pulses 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 phase-matching acceptance bandwidth, and intrinsically low dispersion of noble gases rather than relying on conventional nonlinear crystals.