A single atom detector integrated on an atom chip: fabrication, characterization and application

TL;DR

This paper presents a fully integrated, high-efficiency single atom fluorescence detector on an atom chip, combining precise optical delivery and collection, with detailed characterization and potential for further efficiency improvements.

Contribution

The work introduces a robust, integrated single atom detector on an atom chip with 66% efficiency, novel fiber-based optical setup, and detailed analysis of detection performance and quantum properties.

Findings

Achieved 66% single atom detection efficiency.

Demonstrated near-perfect photon anti-bunching.

Potential to increase efficiency to over 95%.

Abstract

We describe a robust and reliable fluorescence detector for single atoms that is fully integrated into an atom chip. The detector allows spectrally and spatially selective detection of atoms, reaching a single atom detection efficiency of 66%. It consists of a tapered lensed single-mode fiber for precise delivery of excitation light and a multi-mode fiber to collect the fluorescence. The fibers are mounted in lithographically defined holding structures on the atom chip. Neutral 87Rb atoms propagating freely in a magnetic guide are detected and the noise of their fluorescence emission is analyzed. The variance of the photon distribution allows to determine the number of detected photons / atom and from there the atom detection efficiency. The second order intensity correlation function of the fluorescence shows near-perfect photon anti-bunching and signs of damped Rabi-oscillations. With simple improvements one can boost the detection efficiency to > 95%.