Rozhdestvenski hooks in two-photon parametric light scattering

The interference of spontaneous parametric radiation was observed from two nonlinear crystals separated by a macroscopic layer of a linear substance and excited by a common pump beam. In the presence of strong dielectric dispersion in the layer, the frequency-angular spectra display features analogous to the Rozhdestvenski hooks. The hook wavelength corresponds to the compensation of group velocity dispersions in the nonlinear crystals and the layer.