Fundamental tests on higher quantum dimensionality by exploiting the photonic orbital angular momentum

The orbital angular momentum carried by single photons represents a promising resource in the quantum information field. In this paper we report a series of optical schemes adopted for the manipulation of quantum states encoded in the orbital angular momentum exploiting the q-plate device. We further demonstrate the capability of generating hybrid entangled states as well as quantum states in dimension higher than two. Indeed we present the manipulation of ququart states encoded in the polarization and orbital angular momentum, which have been adopted for new quantum cryptographic protocols