Coherence properties of nanofiber-trapped cesium atoms

TL;DR

This paper investigates the coherence properties of cesium atoms trapped near a nanofiber, demonstrating key dephasing times and modeling their limitations, advancing the development of fiber-based quantum networks.

Contribution

It provides experimental measurements and theoretical modeling of atomic coherence times in nanofiber traps, a step toward fiber-integrated quantum networks.

Findings

Reversible dephasing time T2* = 0.6 ms

Irreversible dephasing time T2' = 3.7 ms

Dephasing limited by temperature and heating rate

Abstract

We experimentally study the ground state coherence properties of cesium atoms in a nanofiber-based two-color dipole trap, localized 200 nm away from the fiber surface. Using microwave radiation to coherently drive the clock transition, we record Ramsey fringes as well as spin echo signals and infer a reversible dephasing time $T_2^\ast=0.6$ ms and an irreversible dephasing time $T_2^\prime=3.7$ ms. By theoretically modelling the signals, we find that, for our experimental parameters, $T_2^\ast$ and $T_2^\prime$ are limited by the finite initial temperature of the atomic ensemble and the heating rate, respectively. Our results represent a fundamental step towards establishing nanofiber-based traps for cold atoms as a building block in an optical fiber quantum network.