Highly efficient source for frequency-entangled photon pairs generated in a 3rd order periodically poled MgO-doped stoichiometric LiTaO3 crystal

摘要

We present a highly efficient source for discrete frequency-entangled photonpairs based on spontaneous parametric down-conversion using 3rd order type-0quasi-phase matching in a periodically poled MgO-doped stoichiometric LiTaO3crystal pumped by a 355.66 nm laser. Correlated two-photon states weregenerated with automatic conservation of energy and momentum in two givenspatial modes. These states have a wide spectral range, even under smallvariations in crystal temperature, which consequently results in higherdiscreteness. Frequency entanglement was confirmed by measuring two-photonquantum interference fringes without any spectral filtering.