Quantum coherent control of the photoelectron angular distribution in bichromatic-field ionization of atomic neon

We investigate the coherent control of the photoelectron angular distribution in bichromatic atomic ionization. Neon is selected as target since it is one of the most popular systems in current gas-phase experiments with free-electron lasers (FELSs). In particular, we tackle practical questions, such as the role of the fine-structure splitting, the pulse length, and the intensity. Time-dependent and stationary perturbation theory are employed, and we also solve the time-dependent Schrodinger equation in a single-active electron model. We consider neon ionized by a FEL pulse whose fundamental frequency is in resonance with either 2p-3s or 2p-4s excitation. The contribution of the nonresonant two-photon process and its potential constructive or destructive role for quantum coherent control is investigated.