On the reconstruction of diagonal elements of density matrix of quantum   optical states by on/off detectors
  We discuss a scheme for reconstructing experimentally the diagonal elements of the density matrix of quantum optical states. Applications to PDC heralded photons, multi-thermal and attenuated coherent states are illustrated and discussed in some details. 
G. Brida, M. Genovese, M. Gramegna, M. G. A. Paris, E. Predazzi, E.   Cagliero