Generation of deep ultraviolet sub-2-fs pulses

Opt Lett. 2019 Mar 15;44(6):1308-1311. doi: 10.1364/OL.44.001308.

Abstract

We demonstrate the generation of few-cycle deep ultraviolet pulses via frequency upconversion of 5-fs near-infrared pulses in argon using a laser-fabricated gas cell. The measured spectrum extends from 210 to 340 nm, corresponding to a transform-limited pulse duration of 1.45 fs. We extract from a dispersion-free second-order cross-correlation measurement a pulse duration of 1.9 fs, defining a new record in the deep ultraviolet spectral range.