Self-channeling of a multiterawatt ultra-short laser pulse in argon gas jets - Shadowgraphy imaging

Relativistic self-focusing, self-channeling and filamentation are observed for the first time in the propagation of a 50 fs, 5 TW laser pulse in an underdense optical-field ionized argon gas jet. The conditions of observation of these effects are strongly dependent on the focusing conditions and also on the gas target density gradient at the focusing position.