Abstract
We report on the experimental demonstration of an all-optical 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 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 phase shift even for weak interaction strengths. The scheme is experimentally demonstrated using a coherently prepared dark state in a warm atomic cesium vapor.
- Received 15 May 2008
DOI:https://doi.org/10.1103/PhysRevLett.102.013902
©2009 American Physical Society