Stochastic quasi-phase-matching of the process of spontaneous parametric down-conversion is analyzed. It is shown that spectral, temporal and spatial properties of photon pairs generated in randomly poled crystals are similar to those generated in chirped periodically-poled crystals. Especially, randomly poled crystals are capable to emit photon pairs with ultra-broad spectra. For possible applications, the production of randomly poled nonlinear crystals would be much cheaper than chirped, while their properties are very similar. The work has been done exlusively at the Joint Laboratory of Optics.
a) Coincidence-count rate Rn and b) sum-frequency field intensity as they depend on relative time delay τ for one realization of the random crystal (solid curve), chirped crystal (solid curve with ▵) and an ensemble of random crystals (solid curve with ♦). In b), ideal phase compensation is assumed and curves are normalized.
1Joint Laboratory of Optics, Palacký University and Institute of Physics of Academy of Science of the Czech Republic, 17. listopadu 50A, 772 07 Olomouc, Czech Republic
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