title: Miniature fluorescence detector for single atom observation on a microchip.
abstract: We explore the feasibility of single atom detection on an atom chip by using a tiny fluorescence detector mounted on the chip. Resonant fluorescence from a trapped ultracold atom will be collected with a miniature aspheric lens and taken out of a vacuum chamber through a fiber. During detection, the atom can be held at the focus of the detector with a dipole trapping beam introduced through the same fiber. We have experimentally determined the optical performance of such a detector, taking into account effects such as stray light from the dipole trapping beam and chromatic aberration. The collection efficiency for isotropically emitted radiation is experimentally obtained to be 2.5%. From this, it is estimated that the fluorescence emitted from a single Rb atom will produce a photon count rate of 4.7x10(4) Hz, which is much larger than the shot noise limited background fluctuations.
authors.forename: Akifumi
authors.initials: A
authors.lastname: Takamizawa
authors.forename: Tilo
authors.initials: T
authors.lastname: Steinmetz
authors.forename: Rémi
authors.initials: R
authors.lastname: Delhuille
authors.forename: Theodor W
authors.initials: TW
authors.lastname: Hänsch
authors.forename: Jakob
authors.initials: J
authors.lastname: Reichel