PREPARATION OF NONCLASSICAL FIELD STATES BY RESONANCE FLUORESCENCE INPHOTONIC BAND STRUCTURES

We analyze the near-resonant interaction between a two-level atom with resonance frequency in a photonic band gap and a local-defect field m ode with initially thermal or Poissonian photon statistics. Whereas sp ontaneous decay is forbidden in this case, atomic states dressed by th e defect field can decay via coupling to the mode continuum outside th e band gap. Remarkably, the resulting non-Markovian cascade of dressed states transitions can lead to the accumulation of nearly all of the initial photon-number distribution in a single Fock state, upon measur ing the excitation of the atom emerging from the structure. Under cert ain conditions, such a measurement can yield a correlated combination of two adjacent Fock states, which reflects the initial coherence in e ither the atom or the field. Another striking coherence effect is the non-decaying oscillation (as a function of interaction time) exhibited by Fock-state populations prepared by measuring the final atomic stat e.