Quantum statistics of four-wave mixing by a non-linear resonant   microcavity
  We analyse the correlation and spectral properties of two-photon states resonantly transmitted by a non-linear optical microcavity. We trace the correlation properties of transmitted two-photon states to the decay spectrum of multi-photon resonances in the non-linear microcavity. 
Y. Sherkunov, David M. Whittaker, Henning Schomerus, and Vladimir   Fal'ko
quant-ph