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

Abstract

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