Single-Photon Stored-Light Interferometry

TL;DR

This paper demonstrates a single-photon stored-light interferometer using Rydberg polaritons in cold atoms, enabling phase-sensitive measurements over long delays for potential localized sensing applications.

Contribution

It introduces a novel single-photon interferometry technique utilizing stored light in Rydberg states, extending superposition times and sensitivity for quantum sensing.

Findings

Interferometer achieved a superposition time of 450 ns.

Fringes are sensitive to external fields.

Potential for localized sensing applications.

Abstract

We demonstrate a single-photon stored-light interferometer, where a photon is stored in a laser-cooled atomic ensemble in the form of a Rydberg polariton with a spatial extent of $10 \times1\times1\mu m^3$. The photon is subject to a Ramsey sequence, i.e. `split' into a superposition of two paths. After a delay of up to 450 ns, the two paths are recombined to give an output dependent on their relative phase. The superposition time of 450 ns is equivalent to a free-space propagation distance of 135 m. We show that the interferometer fringes are sensitive to external fields, and suggest that stored-light interferometry could be useful for localized sensing applications.