Our paper on the dynamics of silison nanowires in optical tweezers has been published as A. Irrera et al, 'Photonic torque microscopy of the non-conservative force field for optically trapped silicon nanowires', Nano Letters 16, 4181-4188 (2016).
From the abstract: We measure, by photonic torque microscopy, the nonconservative
rotational motion arising from the transverse components of the
radiation pressure on optically trapped, ultrathin silicon nanowires.
Unlike spherical particles, we find that nonconservative effects have a
significant influence on the nanowire dynamics in the trap. We show that
the extreme shape of the trapped nanowires yields a transverse
component of the radiation pressure that results in an orbital rotation
of the nanowire about the trap axis. We study the resulting motion as a
function of optical power and nanowire length, discussing its
size-scaling behavior. These shape-dependent nonconservative effects
have implications for optical force calibration and optomechanics with
levitated nonspherical particles.