Vector Beam Bending

It is well known that the trajectory of a light beam can curve if the medium in which the beam propagates is inhomogeneous or if the local spacetime is curved. In this paper we present a third possibility and show that a properly-prepared optical beam follows a curved trajectory even in free space where the spacetime is locally flat. By casting the problem in terms of transport of optical intensity, we show that a beam comprising a gradient in state of polarization to second order or higher (i.e., a specifically prepared vector beam) must also follow a curved trajectory. The effect is confirmed experimentally for the case of a second-order gradient in a linearly polarized vector beam.