Towards single-atom detection on a chip
  We investigate the optical detection of single atoms held in a microscopic atom trap close to a surface. Laser light is guided by optical fibers or optical micro-structures via the atom to a photo-detector. Our results suggest that with present-day technology, micro-cavities can be built around the atom with sufficiently high finesse to permit unambiguous detection of a single atom in the trap with 10 $\mu$s of integration. We compare resonant and non-resonant detection schemes and we discuss the requirements for detecting an atom without causing it to undergo spontaneous emission. 
Peter Horak, Bruce G. Klappauf, Albrecht Haase, Ron Folman, Joerg   Schmiedmayer, Peter Domokos, and E. A. Hinds