Generation of sub-3 fs pulses in the deep ultraviolet

We demonstrate generation and measurement of intense deep-ultraviolet light pulses with a duration of similar to 2.8 fs (FWHM of the intensity envelope) and a wavelength distribution between 230 and 290 nm. They emerge via direct frequency upconversion of sub-4 fs laser pulses of a carrier wavelength of similar to 750 nm focused into an Ne-filled, quasi-static gas cell. Dispersion-free, third-order autocorrelation measurements provide access to their temporal intensity profile. (C) 2010 Optical Society of America