title: Realization of an all-optical zero to pi cross-phase modulation jump.
abstract: We report on the experimental demonstration of an all-optical pi cross-phase modulation jump. By performing a preselection, an optically induced unitary transformation, and then a postselection on the polarization degree of freedom, the phase of the output beam acquires either a zero or pi phase shift (with no other possible values). The postselection results in optical loss in the output beam. An input state may be chosen near the resulting phase singularity, yielding a pi phase shift even for weak interaction strengths. The scheme is experimentally demonstrated using a coherently prepared dark state in a warm atomic cesium vapor.
authors.affiliation: Department of Physics and Astronomy, University of Rochester, Rochester, New York 14627, USA. camacho@caltech.edu
authors.forename: Ryan M
authors.initials: RM
authors.lastname: Camacho
authors.forename: P Ben
authors.initials: PB
authors.lastname: Dixon
authors.forename: Ryan T
authors.initials: RT
authors.lastname: Glasser
authors.forename: Andrew N
authors.initials: AN
authors.lastname: Jordan
authors.forename: John C
authors.initials: JC
authors.lastname: Howell