Rotation and Revolution of Optically Trapped Gold Nanorods Induced by the Spin and Orbital Angular Momentum of a Laguerre–Gaussian Vortex Beam

Abstract

Optical trapping, spinning, and orbiting of nanoparticles allow the study of nanoscale mechanical, thermal, and optical effects. A circularly polarized Laguerre–Gaussian beam can simultaneously rotate a gold nanorod about its symmetry axis while revolving it around the beam's symmetry axis. The first motion is rotational in character, whereas the second is translational. Effective temperatures of each motion are experimentally obtained and compared with predictions from the Hot Brownian Motion theory. The results also show the optical‐to‐mechanical torque‐transduction efficiency to be equal for the spin and orbital angular momentum.

Optical manipulation of resonant nanoparticles for thermal and rheological measurements

“…Simultaneous induction of rotational and translational motions with equal efficiencies can be used for temperature dependent microrheological and mechanical measurements in microliter biological samples, which can be in future combined with enhanced Raman or florescent studies. [2]…”

Optomechanical Motions of Gold Dimer’s Spin, Rotation and Revolution Manipulated by Bessel Beam

“…optomechanical motions of these particles become more versatile. For example, utilizing Bessel beam to capture a single GNP or GNR onto an orbit to perform an orbital revolution with spinning [25,26]. The observation of spin-orbit interaction (SOI) of the electromagnetic (EM) eld through the light interacting with these plasmonic nanostructures is noted; a part of SAM of optical vortex may be converted into OAM via the light-matter interaction [23,26].…”

“…Our nding may provide an insight to the optomechanical manipulation of optical vortexes on the motions of GNP clusters.Recently, the study of using an optical vortex, e.g. Laguerre-Gaussian beam or Bessel beam, to manipulate dielectric microparticles, GNPs or SNPs has also drawn considerable attention [21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39]. Since an optical vortex, a structured light, possesses both SAM and OAM simultaneously, the…”