Atomic-orbital-dependent photoelectron momentum distributions for F- ions by orthogonal two-color laser fields

We theoretically investigate the two-dimensional photoelectron momentum distributions (PMDs) of F- ions in an orthogonal two-color laser field with equal intensities. The PMDs for different atomic orbitals are simulated by an exact solution to the three-dimensional time-dependent Schrodinger equation and the strong-field approximation method, respectively. Through the comparison of the calculations of these methods, we confirm that the asymptotic behavior of initial bound-state wave function plays a crucial role in forming the main shape of PMDs at large momenta. Based on the saddle-point method and the imaginary time theory, we show that the PMDs of F- ions can be decoded to reveal the definite imprint of the photoelectron sub-barrier phase from the subcycle interference structures. We demonstrate the sub-barrier phases from different atomic orbitals have different impacts on the subcycle interference structures.