ИСТИНА

We present an experimental platform for polarization-entangled photon pairs generation and characterization. The photon pairs are generated using the double-crystal scheme in the presence of the Migdall effect and fully characterized with quantum state tomography. The platform is used to study the dependence of the SPDC polarization on the scattering direction (the Migdall effect). We demonstrate the Migdall effect can significantly decrease the entanglement of produced states. The compensation techniques to overcome the negative action of the Migdall effect and to generate photon pairs in a maximally entangled state are also developed, and 2.7 times entanglement increase is demonstrated