Nonperturbative signatures in pair production for general elliptic polarization fields

The momentum signatures in nonperturbative multiphoton pair production for general elliptic polarization electric fields are investigated by employing the real-time DiracHeisenberg-Wigner formalism. For a linearly polarized electric field we find that the positions of the nodes in momentum spectra of created pairs depend only on the electric-field frequency. The polarization of external fields could not only change the node structures or even make the nodes disappear but also change the thresholds of pair production. The momentum signatures associated to the node positions in which the even-number photon pair creation process is forbidden could be used to distinguish the orbital angular momentum of created pairs on the momentum spectra. These distinguishable momentum signatures could be relevant for providing the output information of created particles and also the input information of ultrashort laser pulses. Copyright (C) EPLA, 2015