title: Absorption spectroscopy at the limit: detection of a single atom.
abstract: We investigate the sensitivity limit of absorption spectroscopy. An experiment is described in which the decrease in transmitted light intensity that is due to absorption by a single, electromagnetically confined atomic ion is observed.
authors.forename: D J
authors.initials: DJ
authors.lastname: Wineland
authors.forename: W M
authors.initials: WM
authors.lastname: Itano
authors.forename: J C
authors.initials: JC
authors.lastname: Bergquist