Coherent and Dynamic Beam Splitting based on Light Storage in Cold Atoms

TL;DR

This paper presents a coherent, dynamic beam splitter using light storage in cold atoms, enabling control over splitting ratios, phases, and frequencies, with potential applications in quantum information processing.

Contribution

It introduces a novel active beam splitter based on light storage in cold atoms, allowing dynamic control of optical parameters, which was not achievable with traditional static beam splitters.

Findings

High visibility interference confirms coherence.

Dynamic control over splitting ratio and phase demonstrated.

Potential to replace multiple optical elements in quantum systems.

Abstract

We demonstrate a coherent and dynamic beam splitter based on light storage in cold atoms. An input weak laser pulse is first stored in a cold atom ensemble via electromagnetically-induced transparency (EIT). A set of counter-propagating control fields, applied at a later time, retrieves the stored pulse into two output spatial modes. The high visibility interference between the two output pulses clearly demonstrates that the beam splitting process is coherent. Furthermore, by manipulating the control lasers, it is possible to dynamically control the storage time, the power splitting ratio, the relative phase, and the optical frequencies of the output pulses. The active beam splitter demonstrated in this work is expected to significantly reduce the resource requirement in photonic quantum information and in all-optical information processing as a single cold atom ensemble can functionally replace a variety of optical elements, including beam splitters, mirrors, phase shifters, and optical quantum memories.