Two-photon entanglement by atoms with Zeeman-split sublevels
David Petrosyan, Gershon Kurizki
Abstract
We propose a simple scheme for highly efficient nonlinear interaction between two weak optical fields. The scheme is based on the attainment of electromagnetically induced transparency simultaneously for both fields via transitions between magnetically split F=1 atomic sublevels, in the presence of a single driving field. Thereby, equal slow group velocities and cross-coupling of the weak fields over long distances are achieved. Depending on the choice of parameters, this scheme can either yield giant cross-phase modulation or ultrasensitive two-photon switching, which can be used to fully entangle the two fields.