  The momentum carried by structured light fields exhibits a rich array of
surprising features. In this work, we generate transverse orbital angular
momentum (TOAM) in the interference field of two parallel and
counterpropagating linearly-polarised focused beams, synthesising an array of
identical handedness vortices carrying intrinsic TOAM. We explore this
structured light field using an optomechanical sensor, consisting of an
optically levitated silicon nanorod, whose rotation is a probe of the optical
angular momentum, which generates an exceptionally large torque. This simple
creation and direct observation of TOAM will have applications in studies of
fundamental physics, the optical manipulation of matter and quantum
optomechanics.
