Carbon multicharged ions emission from femtosecond laser plume.

• Multicharged carbon ions are produced from femtosecond laser ablation. • Up to C6+ ions are produced from a laser plasma. • Carbon ion signal fits a shifted Maxwell-Boltzmann distribution. • External electric field along the plasma expansion increases ion extraction. Carbon ion emission from femtosecond laser ablation of a glassy carbon target is studied. A Ti:sapphire laser (pulse duration τ ~ 150 fs, wavelength λ = 800 nm, laser fluence F ≤ 6.4 J cm−2) is used to ablate the carbon target while ion emission is detected by a time-of-flight detector equipped with a three-grid retarding field analyzer. A strong effect of the laser pulse fluence on the yield of carbon ions is observed. Up to C6+ ions are detected. The carbon ion time-of-flight signal is fit to a shifted Maxwell-Boltzmann distribution and used to extrapolate the effective plasma ion temperature T ieff = 6.9 eV. Applying an external electric field along the plasma expansion direction increases ion extraction, possibly due to the retrograde motion of the plasma-vacuum edge. [ABSTRACT FROM AUTHOR]