Free-Space Quantum Key Distribution by Rotation-Invariant Twisted Photons

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Author(s)
Vallone, Giuseppe
D'Ambrosio, Vincenzo
Sponselli, Anna
Slussarenko, Sergei
Marrucci, Lorenzo
Sciarrino, Fabio
Villoresi, Paolo
Griffith University Author(s)
Year published
2014
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Show full item recordAbstract
“Twisted photons” are photons carrying a well-defined nonzero value of orbital angular momentum
(OAM). The associated optical wave exhibits a helical shape of the wavefront (hence the name) and
an optical vortex at the beam axis. The OAM of light is attracting a growing interest for its potential
in photonic applications ranging from particle manipulation, microscopy and nanotechnologies, to
fundamental tests of quantum mechanics, classical data multiplexing and quantum communication.
Hitherto, however, all results obtained with optical OAM were limited to laboratory scale. Here we
report the experimental demonstration of a ...
View more >“Twisted photons” are photons carrying a well-defined nonzero value of orbital angular momentum (OAM). The associated optical wave exhibits a helical shape of the wavefront (hence the name) and an optical vortex at the beam axis. The OAM of light is attracting a growing interest for its potential in photonic applications ranging from particle manipulation, microscopy and nanotechnologies, to fundamental tests of quantum mechanics, classical data multiplexing and quantum communication. Hitherto, however, all results obtained with optical OAM were limited to laboratory scale. Here we report the experimental demonstration of a link for free-space quantum communication with OAM operating over a distance of 210 meters. Our method exploits OAM in combination with optical polarization to encode the information in rotation-invariant photonic states, so as to guarantee full independence of the communication from the local reference frames of the transmitting and receiving units. In particular, we implement quantum key distribution (QKD), a protocol exploiting the features of quantum mechanics to guarantee unconditional security in cryptographic communication, demonstrating error-rate performances that are fully compatible with real-world application requirements. Our results extend previous achievements of OAM-based quantum communication by over two orders of magnitudes in the link scale, providing an important step forward in achieving the vision of a worldwide quantum network.
View less >
View more >“Twisted photons” are photons carrying a well-defined nonzero value of orbital angular momentum (OAM). The associated optical wave exhibits a helical shape of the wavefront (hence the name) and an optical vortex at the beam axis. The OAM of light is attracting a growing interest for its potential in photonic applications ranging from particle manipulation, microscopy and nanotechnologies, to fundamental tests of quantum mechanics, classical data multiplexing and quantum communication. Hitherto, however, all results obtained with optical OAM were limited to laboratory scale. Here we report the experimental demonstration of a link for free-space quantum communication with OAM operating over a distance of 210 meters. Our method exploits OAM in combination with optical polarization to encode the information in rotation-invariant photonic states, so as to guarantee full independence of the communication from the local reference frames of the transmitting and receiving units. In particular, we implement quantum key distribution (QKD), a protocol exploiting the features of quantum mechanics to guarantee unconditional security in cryptographic communication, demonstrating error-rate performances that are fully compatible with real-world application requirements. Our results extend previous achievements of OAM-based quantum communication by over two orders of magnitudes in the link scale, providing an important step forward in achieving the vision of a worldwide quantum network.
View less >
Journal Title
Physical Review Letters
Volume
113
Copyright Statement
© 2014 American Physical Society. This is the author-manuscript version of this paper. Reproduced in accordance with the copyright policy of the publisher. Please refer to the journal's website for access to the definitive, published version.
Subject
Mathematical sciences
Physical sciences
Quantum information, computation and communication
Quantum optics and quantum optomechanics
Engineering