Demonstration of a state-insensitive, compensated nanofiber trap

TL;DR

This paper demonstrates an optical nanofiber trap for single Cs atoms that minimizes light shifts and surface interactions, enabling improved quantum optics and spectroscopy applications.

Contribution

It introduces a state-insensitive, compensated nanofiber trap using magic wavelengths, reducing differential and vector light shifts for precise atomic control.

Findings

Achieved trapping of single Cs atoms ~215 nm from nanofiber surface.

Measured atomic absorption linewidth close to free-space value.

Observed optical depth per atom of approximately 0.08.

Abstract

We report the experimental realization of an optical trap that localizes single Cs atoms ~215 nm from surface of a dielectric nanofiber. By operating at magic wavelengths for pairs of counter-propagating red- and blue-detuned trapping beams, differential scalar light shifts are eliminated, and vector shifts are suppressed by ~250. We thereby measure an absorption linewidth \Gamma/2\pi = 5.7 \pm 0.1 MHz for the Cs 6S1/2,F=4 - 6P3/2,F'=5 transition, where \Gamma/2\pi = 5.2 MHz in free space. Optical depth d~66 is observed, corresponding to an optical depth per atom d_1~0.08. These advances provide an important capability for the implementation of functional quantum optical networks and precision atomic spectroscopy near dielectric surfaces.