Tunable 30-femtosecond pulses across the deep ultraviolet

Intense femtosecond pulses in the deep ultraviolet are generated by phase-matched four-wave mixing in an argon-filled hollow waveguide using 100-fs pulses from a commercial Ti:sapphire regenerative amplifier. Despite the long duration driving pulses, pulses as short as 25 fs with energies of > 5 mu J at 266 nm are produced after a simple double-pass prism compressor. In combination with an infrared optical parametric amplifier, tunable pulses are obtained over the 224-240 nm range with energies exceeding 1 mu J, bandwidths of 5 nm and typical compressed pulsewidths of 31 fs. Excellent mode and stability make this a promising source for deep ultraviolet pump-probe experiments. (c) 2005 American Institute of Physics.