Optical trap for an atom around the midpoint between two coupled identical parallel optical nanofibers

TL;DR

This paper proposes a method to trap cesium atoms at the midpoint between two parallel optical nanofibers using a specific guided light mode, achieving deep, stable traps with long coherence times.

Contribution

It introduces a novel optical trapping scheme utilizing a blue-detuned mode in coupled nanofibers, with detailed analysis of parameters affecting trap stability and depth.

Findings

Trap depth of about 1 mK achieved

Coherence time of several seconds demonstrated

Trap lifetime extends to several hours

Abstract

We study the trapping of a ground-state cesium atom in a small region around the midpoint between two coupled identical parallel optical nanofibers. We suggest to use a blue-detuned guided light field in the odd $\mathcal{E}_z$-sine array mode to produce an optical potential with a local minimum of exact zero at the midpoint between the nanofibers. We find that the effects of the van der Waals potential on the total trapping potential around the minimum point are not significant when the fiber separation distance and the power of the guided light field are large. For appropriate realistic parameters, a net trapping potential with a significant depth of about 1 mK, a large coherence time of several seconds, and a large recoil-heating-limited trap lifetime of several hours can be obtained. We investigate the dependencies of the trapping potential on the power of the guided light field, the fiber radius, the wavelength of light, and the fiber separation distance.