  The effects of electric field polarizations on pair production from a vacuum
are investigated numerically by employing the real-time Dirac-Heisenberg-Wigner
formalism. For few-cycle fields, it is found that the interference pattern in
momentum spectra is absent and the circular distortion of momentum distribution
becomes more apparent with the increase of polarization. For multi-cycle
fields, it is found that the interference effects in momentum spectra are
obvious. And as the polarization increases, the momentum distribution is split
into two parts in the momentum $q_y$ direction first and then two separated
parts are connected into a ring. The effects of polarizations on the number
density of created particles exhibits two different characteristics. For a
small laser frequency, the particle number density deceases with the
polarization, while for a large laser frequency, the relation between them is
sensitive to the field frequency nonlinearly. Some interpretations for the
obtained results in this study, which is expected to be valuable to deepen the
understanding of pair production in complex fields and also helpful for the
study associated to strong-field ionization.
