Compression of UV femtosecond laser pulses focused into a gas cell filled
with xenon is reported numerically. With a large negative Kerr index and normal
dispersion, xenon promotes temporal modulational instability (MI) which can be
monitored to shorten ~ 100 fs pulses to robust, singly-peaked waveforms
exhibiting a fourfold compression factor. Combining standard MI theory with a
variational approach allows us to predict the beam parameters suitable for
efficient compression. At powers < 30 MW, nonlinear dispersion is shown to
shift the pulse temporal profile to the rear zone.Comment: 4 pages, 4 figure