An all-optical atomic Controlled-NOT (CNOT)/polarization gate operation is demonstrated with low light intensities in a room-temperature atomic medium. Using a Polarization-Selective-Kerr-Phase-Shift (PSKPS) technique, a π phase shift is written to only one of the two circularly-polarized components of a linearly-polarized input signal field by a weak phase-control field with "magic" detuning. At the exit of the medium, the signal field maintains its original strength but acquires a 90o linear polarization rotation, demonstrating the first fast, high-fidelity CNOT/polarization gate operation in a room-temperature atomic medium. This development opens the realm of possibilities for potential future extremely low light level telecommunication and information processing systems.
@article{arxiv.1407.1126,
title = {All-Optical, High-Fidelity Polarization Gate Using Room-Temperature Atomic Vapor},
author = {Runbing Li and Chengjie Zhu and L. Deng and E. W. Hagley},
journal= {arXiv preprint arXiv:1407.1126},
year = {2014}
}