Photon angular momentum based multidimensional quantum key distribution

In this invited paper, we describe the photon angular momentum based entanglement assisted quantum key distribution (QKD) protocols, analyse their security, and determine the secure finite key fraction rates. Two types of entanglement-assisted protocols, namely two-basis and (D+1)-basis protocols (D is dimensionality of corresponding Hilbert space), have been identified as the most promising. We further analyse the implementation of the qubit gates required for these protocols. We demonstrate that photon angular momentum based QKD protocols significantly outperform corresponding two-dimensional QKD protocols in terms of the finite secret key rates.