Compression of ultrashort UV pulses in a self-defocusing gas

TL;DR

This paper demonstrates numerically that UV femtosecond pulses can be compressed in xenon gas by exploiting modulational instability, achieving significant pulse shortening with predictable parameters.

Contribution

It introduces a combined MI theory and variational approach to predict optimal conditions for UV pulse compression in a self-defocusing gas.

Findings

Pulse compression factor of four achieved.

Nonlinear dispersion shifts pulse profile at powers below 30 MW.

Xenon gas promotes effective temporal modulational instability.

Abstract

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.