Study on quantum cryptography using orbital angular momentum states of photons

Abstract

We present a simple quantum cryptographic scheme that encodes information in two orthogonal orbital angular momentum states. The states used in this scheme are invariant under rotations of the propagation direction，making this implementation independent of the alignment between the reference frames of Alice and Bob. Besides，since the two orbital angular momentum states are orthogonal，100% use of the photons is attained，which increases the key generation rate of the protocol.