Free-space quantum key distribution by rotation-invariant twisted photons

Understand

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.