Quantum properties of counterpropagating two-photon states generated in a planar waveguide
Jan Peřina · Physical Review A · 2008
A nonlinear planar waveguide pumped by a beam orthogonal to its surface may serve as a versatile source of photon pairs. By changing the pump-pulse duration, pump-beam transverse width, and angular decomposition of the pump-beam frequency characteristics of a photon pair, including the spectral widths of signal and idler fields, the pair time duration as well as the degree of entanglement of the two fields, can be changed significantly. Using the measured spectral widths of the down-converted fields and the width of a coincidence-count dip in a Hong-Ou-Mandel interferometer, the entropy of entanglement can be determined.