We propose a technique for the preparation of Fock states of a harmonic oscillator strongly coupled to a single two-level atomic transition based on the observation of quantum jumps. Examples are taken from the fields of cavity QED and ion trapping, where photon number states and number states of the quantized atomic motion may be prepared, respectively.

• Received 14 September 1992

DOI:https://doi.org/10.1103/PhysRevLett.70.762