Anti-symmetric chirp transfer in high-energy ultraviolet via four-wave mixing in gas

Abstract: Customizing the pulse shaping of femtosecond pulses remains a key challenge in ultrafast optics. Programmable shaping for ultraviolet (UV) pulses is constrained by the transmission properties and damage threshold of the dielectric materials used. As a stepping stone toward overcoming this broad challenge, we demonstrate an anti-symmetric dispersion transfer from near-infrared (NIR) pulses to UV pulses through chirped-four-wave-mixing (CFWM) in argon gas. Positively chirped NIR pulses map quasi-linearly to negatively chirped UV in a gas-filed hollow capillary fiber (HCF), achieving a conversion efficiency exceeding 13%. This approach expands the foundations of UV pulse shaping, enabling broadband frequency conversion by leveraging the large acceptance angle and intrinsically low dispersion of noble gases, rather than relying on conventional nonlinear crystals. Spectro-temporally customizing high-energy, ultrashort UV pulses is a pivotal technique for applications in ultrafast dynamics, high-precision spectroscopy, future nuclear clocks, charged-particle and radiation sources, and industrial microfabrication.