Observing quantum gases in real time: Single-atom detection on a chip

Abstract

Single magnetically trapped $^{87}\text{R}\text{b}$ atoms on an atom chip are detected with $67\ifmmode\pm\else\textpm\fi{}12\text{ }%$ efficiency by three photon ionization and subsequent ion detection in a channel electron multiplier. State selective detection of single atoms and high-resolution optical spectroscopy on trapped atom clouds are demonstrated. The temperature and particle density of a trapped atomic gas is monitored in situ and in real time with negligible atom loss due to ionization below 5%.