Multiple Ionization of Atoms by 25 and 7 fs Laser Pulses

Abstract. Double, triple and fourfold ionization of rare gas atoms has been studied using a “reaction microscope”. We show that ionization dynamics drastically depends on atomic species and present the first data obtained with few-cycle pulses. Since the first experimental observation of doubly charged ions produced by intense laser field [1], many-electron dynamics in laser-induced ionization has been the subject of numerous experimental and theoretical studies. It was soon found out that the yields of second and higher charge states produced by intense linearly polarized laser pulses exceed significantly those expected for independent successive removal of two or more electrons. The origin of this enhancement (which was called “non-sequential ” ionization) remained controversial until 2000 when first measurements of recoil ion momentum distributions [2,3] along with the results of earlier experiments using circularly polarized light [4] provided convincing evidences in favour of the so-called “recollision ” model. However, the details of the double ionization dynamics are still far from being completely understood. In particular, one o