Photon correlations in waveguide lattices

Researchers made efforts to explore the possibility of manipulating non-classical states of light using waveguide lattices. The researchers investigated the correlations between two photons in the lattice to reveal the quantum nature of the light propagating in the waveguides. The quantum features of the light at the output of the lattice were revealed by the probability of detecting the two photons at the outputs of waveguides. There were two indistinguishable paths leading to the same final state, as the photons were identical. It was demonstrated that some special features of such a quantum mechanical interference was captured using classical intensity-correlation measurements with phase-averaged coherent states. The quantum mechanical probability of detecting one photon at each of the waveguides was related to the classical intensity-correlation between them.