Preparation of biphotons in arbitrary polarization states
L. A. Krivitskiı̆, S. P. Kulik, Gleb Maslennikov, Maria V. Chekhova · Journal of Experimental and Theoretical Physics · 2005
An experiment on preparation of entangled photon pairs (biphotons) in an arbitrary polarization state is described. The biphotons are qutrits (three-state quantum systems). They can be used in ternary quantum cryptography protocols. A theoretically derived orthogonality criterion for the prepared biphotons is validated experimentally. The criterion can be used to identify orthogonal biphoton states.