Pair production in laser fields oscillating in space and time.

The production of electron-positron pairs from vacuum by counterpropagating laser beams of linear polarization is calculated. In contrast with the usual approximate approach, the spatial dependence and magnetic component of the laser field are taken into account. We show that the latter strongly affects the creation process at high laser frequency: the production probability is reduced, the kinematics is fundamentally modified, the resonant Rabi-oscillation pattern is distorted, and the resonance positions are shifted, multiplied, and split.