  Among the optical degrees of freedom, the orbital angular momentum of light
provides unique properties, including mechanical torque action with
applications for light manipulation, enhanced sensitivity in imaging techniques
and potential high-density information coding for optical communication
systems. Recent years have also seen a tremendous interest in exploiting
orbital angular momentum at the single-photon level in quantum information
technologies. In this endeavor, here we demonstrate the implementation of a
quantum memory for quantum bits encoded in this optical degree of freedom. We
generate various qubits with computer-controlled holograms, store and retrieve
them on demand. We further analyse the retrieved states by quantum tomography
and thereby demonstrate fidelities exceeding the classical benchmark,
confirming the quantum functioning of our storage process. Our results provide
an essential capability for future networks exploring the promises of orbital
angular momentum of photons for quantum information applications.
