Physical Review Letters

Realization of Four-Level Qudits Using Biphotons

Ekaterina V. Moreva, Gleb Maslennikov, Stanislav S. Straupe, S. P. Kulik

Published Jul 13, 2006• 74 citations

Abstract

The novel experimental realization of four-level optical quantum systems (ququarts) is presented. We exploit the polarization properties of the frequency nondegenerate biphoton field to obtain such systems. A simple method that does not rely on am interferometer is used to generate and measure the sequence of states that can be used in quantum key distribution protocol.

DOI: 10.1103/physrevlett.97.023602

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