Electrically engineering synthetic magnetic fields for polarized photons

Abstract

Polarized photons are, in essence, neutral particles and therefore do not couple directly to external fields, thus hampering the effective interaction of photons with external fields. Here, we theoretically identify an equivalent spin-1/2 model for polarized photons and synthesize a magnetization vector for coupling differently polarized photons in an engineered anisotropic medium. The synthetic magnetic field can be electrically engineered to manipulate the magnetic moments of the pseudo-spin-1/2 photons, leading to observation of the Lorentz force and analogous Stern–Gerlach effect. We experimentally demonstrate these fundamental effects by using different spins, including purely single-polarization spins and mutually two-polarization mixing spins. We also demonstrate the higher-order Stern–Gerlach effect by using spins having nontrivial topological structures. Our findings could enable polarization-based elements with potential applications in polarization selection and conversion, benefiting classical and quantum information processing.