ИСТИНА

In our work we investigate both theoretically and experimentally strong spatial correlations in macroscopic quantum states of light referred to as bright squeezed vacuum (BSV). Their important advantage is the multimode structure, which offers a larger capacity for the encoding of quantum information. To describe theoretically these states we develop a generalized fully analytical approach, based on the concept of independent collective (Schmidt) modes. In the frame of the Heisenberg picture we obtain fully analytical solution for the spatial evolution of the photon-creation operators either for the collective Schmidt modes or for the plane wave modes. Using the obtained solution we calculate analytically the angular distribution of non-linear signal as well as different correlation characteristics and obtain a very good agreement with experimental data. Our theory explains many new interesting spatial correlation effects observed experimentally in BSV.