Feedback-optimized extraordinary optical transmission of continuous-variable entangled states

Abstract

We report on the feedback-optimized extraordinary optical transmission of continuous-variable entangled states through a hexagonal metal-hole array. The continuous-variable entanglements from a nondegenerate optical parametric amplifier are first demonstrated to survive after a photon-plasmon-photon conversion process. By controlling the reflected light from the metal-hole array, a significant enhancement of quantum correlations has then been experimentally achieved, compared to the case without such coherent feedback control. This result presents a useful technique to efficiently recover the substantial reflective losses in plasmonic circuits for quantum information processing.