All-Optical, High-Fidelity Polarization Gate Using Room-Temperature Atomic Vapor

TL;DR

This paper demonstrates a high-fidelity, all-optical polarization gate using room-temperature atomic vapor, enabling low-light quantum information processing with potential applications in telecommunication.

Contribution

It introduces a novel PSKPS technique to achieve fast, high-fidelity CNOT/polarization gate operation at room temperature with low light intensities.

Findings

Achieved a $ ext{pi}$ phase shift on one polarization component.

Maintained signal strength while rotating polarization by 90 degrees.

First demonstration of such a gate in room-temperature atomic medium.

Abstract

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 $\pi$ 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 90$^{\rm o}$ 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.