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Published March 2015 | Published + Submitted
Journal Article Open

High-dimensional quantum cryptography with twisted light


Quantum key distribution (QKD) systems often rely on polarization of light for encoding, thus limiting the amount of information that can be sent per photon and placing tight bounds on the error rates that such a system can tolerate. Here we describe a proof-of-principle experiment that indicates the feasibility of high-dimensional QKD based on the transverse structure of the light field allowing for the transfer of more than 1 bit per photon. Our implementation uses the orbital angular momentum (OAM) of photons and the corresponding mutually unbiased basis of angular position (ANG). Our experiment uses a digital micro-mirror device for the rapid generation of OAM and ANG modes at 4 kHz, and a mode sorter capable of sorting single photons based on their OAM and ANG content with a separation efficiency of 93%. Through the use of a seven-dimensional alphabet encoded in the OAM and ANG bases, we achieve a channel capacity of 2.05 bits per sifted photon. Our experiment demonstrates that, in addition to having an increased information capacity, multilevel QKD systems based on spatial-mode encoding can be more resilient against intercept-resend eavesdropping attacks.

Additional Information

© 2015 IOP Publishing Ltd and Deutsche Physikalische Gesellschaft. Content from this work may be used under the terms of the Creative Commons Attribution 3.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI. Received 5 October 2014. Accepted 16 February 2015. Published 20 March 2015. We acknowledge helpful discussion with Glenn A Tyler of the Optical Sciences Company. This work was financially supported by DARPA/DSO InPho program, the US Air Force under contract FA9453-14-M-0317, the UK EPSRC under Programme Grant COAM, and the Canadian Excellence Research Chair (CERC) program. OSML acknowledges support from CONACyT. Mehul Malik acknowledges support from European Commission through a Marie Curie Fellowship.

Attached Files

Submitted - 1402.7113.pdf

Published - Mirhosseini_2015_New_J._Phys._17_033033.pdf


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August 20, 2023
August 20, 2023