A deterministic detector for vector vortex states

Ndagano, B., Nape, I., Perez-Garcia, B., Scholes, S., Hernandez-Aranda, R. I., Konrad, T., Lavery, M. P.J. and Forbes, A. (2017) A deterministic detector for vector vortex states. Scientific Reports, 7, 13882. (doi: 10.1038/s41598-017-12739-z) (PMID:29066715) (PMCID:PMC5654751)

Abstract

Encoding information in high-dimensional degrees of freedom of photons has led to new avenues in various quantum protocols such as communication and information processing. Yet to fully benefit from the increase in dimension requires a deterministic detection system, e.g., to reduce dimension dependent photon loss in quantum key distribution. Recently, there has been a growing interest in using vector vortex modes, spatial modes of light with entangled degrees of freedom, as a basis for encoding information. However, there is at present no method to detect these non-separable states in a deterministic manner, negating the benefit of the larger state space. Here we present a method to deterministically detect single photon states in a four dimensional space spanned by vector vortex modes with entangled polarisation and orbital angular momentum degrees of freedom. We demonstrate our detection system with vector vortex modes from the |[Formula: see text]| = 1 and |[Formula: see text]| = 10 subspaces using classical and weak coherent states and find excellent detection fidelities for both pure and superposition vector states. This work opens the possibility to increase the dimensionality of the state-space used for encoding information while maintaining deterministic detection and will be invaluable for long distance classical and quantum communication.

• Item Type: Articles
• Additional Information: s. B.N. acknowledges fnancial support from the National Research Foundation of South Africa and I.N. from the Department of Science and Technology (South Africa). B.P.G. and R.I.H. acknowledge support from CONACyT.
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Lavery, Professor Martin
• Authors: Ndagano, B., Nape, I., Perez-Garcia, B., Scholes, S., Hernandez-Aranda, R. I., Konrad, T., Lavery, M. P.J., and Forbes, A.
• College/School: College of Science and Engineering > School of Engineering > Electronics and Nanoscale Engineering
• Journal Name: Scientific Reports
• Publisher: Nature Research
• ISSN: 2045-2322
• ISSN (Online): 2045-2322
• Copyright Holders: Copyright © 2017 The Authors
• First Published: First published in Scientific Reports 7: 13882
• Publisher Policy: Reproduced under a Creative Commons License