Strong field double ionization by elliptically polarized few-cycle laser pulses

With the classical ensemble model, we have investigated double ionization of xenon atoms by an elliptically polarized few-cycle laser pulse at intensity 4×1014 W/cm2. The results show that sequential double ionization (SDI) and nonsequential double ionization (NSDI) exist simultaneously with this laser field. The momentum distributions of SDI and NSDI both strongly depend on the carrier-envelop phase (CEP). Back analysis shows that the ionization times of both electrons in SDI and the recollision time in NSDI have a strong dependence on CEP, which is responsible for the CEP-dependent momentum distributions of SDI and NSDI. The rich details of SDI and NSDI are intuitively revealed by back analysis of the classical trajectories.