High-Energy Ions Emitted from Ar Clusters Irradiated by Intense Femtosecond Laser Pulses

We have experimentally studied the energy spectra of Ar ions emitted from Ar clusters irradiated by intense femtosecond laser pulses. The Ar clusters were produced in the adiabatic expansion of Ar gas into vacuum at high backing pressures. The laser peak intensity was about 2 Χ10^l6W/cm² with a pulse duration of 45fs. The maximum and the average energies of Ar ions are 0.2MeV and 15keV at a backing pressure of 2.5MPa, respectively. They are almost independent of the backing pressures in the range of 0.6 to 4.5 MPa.