TY - JOUR SN - 1530-6992 N1 - Copyright © 2016 American Chemical Society. This document is the Accepted Manuscript version of a Published Work that appeared in final form in Nano Letters, copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see http://pubs.acs.org/doi/abs/10.1021/acs.nanolett.6b01059 ID - discovery1507864 AV - public EP - 4188 JF - Nano Letters N2 - 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. VL - 16 SP - 4181 UR - http://dx.doi.org/10.1021/acs.nanolett.6b01059 TI - Photonic Torque Microscopy of the Nonconservative Force Field for Optically Trapped Silicon Nanowires KW - Brownian motion KW - Optical tweezers KW - nonequilibrium dynamics KW - silicon nanowires IS - 7 Y1 - 2016/07/13/ A1 - Irrera, A A1 - Magazzù, A A1 - Artoni, P A1 - Simpson, SH A1 - Hanna, S A1 - Jones, PH A1 - Priolo, F A1 - Gucciardi, PG A1 - Maragò, OM ER -