Universal unitary gate for single-photon spinorbit four-dimensional states

TL;DR

This paper proposes a universal optical device capable of performing arbitrary unitary transformations on single-photon spin-orbit four-dimensional states, enabling advanced quantum information processing and manipulation of light's combined orbital angular momentum and spin.

Contribution

It introduces a practical design for a universal unitary gate for spin-orbit photon states using existing optical technology, filling a key gap in quantum photonics.

Findings

Design of a universal unitary gate for spin-orbit states

Device operates with existing optical components

Potential applications in quantum information and light manipulation

Abstract

The recently demonstrated possibility of entangling opposite values of the orbital angular momentum (OAM) of a photon with its spin enables the realization of nontrivial one-photon spinorbit four-dimensional states for quantum information purposes. Hitherto, however, an optical device able to perform arbitrary unitary transformations on such spinorbit photon states has not been proposed yet. In this work we show how to realize such a ``universal unitary gate'' device, based only on existing optical technology, and describe its operation. Besides the quantum information field, the proposed device may find applications wherever an efficient and convenient manipulation of the combined OAM and spin of light is required.