Nonrelativistic strong-field photoionization without making the dipole approximation

Within the context of the time-reversed S-matrix approach to photoionization, and employing a recently proposed strong-field solution to the Schrodinger equation, analytic expressions for the atomic photoionization rates are obtained here without using the dipole approximation. We show that the absorbed photon,momentum shows rip as a forward-directed momentum component for the photoelectron. All the expressions reported in this work have the correct limits when the dipole approximation is used.