Photon spin-to-orbital angular momentum conversion via an electrically tunable q-plate

Exploiting electro-optic effects in liquid crystals, we achieved real-time control of the retardation of liquid-crystal-based q-plates through an externally applied voltage. Electro-optic q-plates can be operated as electrically driven converters of photon spin into orbital angular momentum, enabling a variation of the orbital angular momentum probabilities of the output photons over a time scale of milliseconds