2005/11/30 by Simon Gröblacher, Simon Groeblacher, Thomas Jennewein +3 · 8 citations
Computer Science · Physics and Astronomy · #Orbital Angular Momentum in Optics #Quantum Information and Cryptography #Quantum Mechanics and Applications #quant-ph
paper · pdf · doi:10.1088/1367-2630/8/5/075
published as New J. Phys. 8 (2006) 75 · New version includes additional references and a few minor changes to the manuscript
openalex publication_date 2006/05/26 · arxiv created 2006/06/13 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/30
We produce two identical keys using, for the first time, entangled trinary quantum systems (qutrits) for quantum key distribution. The advantage of qutrits over the normally used binary quantum systems is an increased coding density and a higher security margin. The qutrits are encoded into the orbital angular momentum of photons, namely Laguerre–Gaussian modes with azimuthal index l + 1, 0 and −1, respectively. The orbital angular momentum is controlled with phase holograms. In an Ekert-type protocol the violation of a three-dimensional Bell inequality verifies the security of the generated keys. A key is obtained with a qutrit error rate of approximately 10%.