Demonstration of a State-Insensitive, Compensated Nanofiber Trap

Abstract

We report the experimental realization of an optical trap that localizes single Cs atoms similar or equal to 215 nm from the surface of a dielectric nanofiber. By operating at magic wavelengths for pairs of counterpropagating red-and blue-detuned trapping beams, differential scalar light shifts are eliminated, and vector shifts are suppressed by approximate to 250. We thereby measure an absorption linewidth Gamma/2 pi = 5.7 +/- 0.1 MHz for the Cs 6S(1/2), F = 4 -> 6P(3/2), F' = 5 transition, where Gamma(0)/2 pi = 5.2 MHz in free space. An optical depth d similar or equal to 66 is observed, corresponding to an optical depth per atom d(1) similar or equal to 0.08. These advances provide an important capability for the implementation of functional quantum optical networks and precision atomic spectroscopy near dielectric surfaces.