Accurate semiclassical method for constructing photoelectron momentum distribution for atoms in intense few-cycle laser pulses

We provide detailed theoretical investigations of three-dimensional (3D) photoelectron momentum distribution (PMD) in low energy region for atoms in an intense elliptically polarized laser pulse. By using a relatively long pulse, separate individual above-threshold ionization (ATI) shells can be clearly identified. For Hydrogen atom, we confirm the earlier experimental and theoretical results that the offset angle increases with increased ATI ring, which has been attributed as due to the nonadiabaticity in strong-field ionization. We further show that the exact numerical solutions of the time-dependent Schrodinger equation (TDSE) can be accurately reproduced by our recently developed strong-field Herman-Kluk (SFHK) semiclassical method. Aided by the SHFK and TDSE results, we extend this analysis to Argon with atomic states of m=+1 and m=-1 and shed light on this behavior when the atomic ring currents are of different directions.

This work was supported by the U.S. Department of Energy (DOE), Office of Science, Basic Energy Sciences (BES) under Award Number DE-SC0023192.