Optical matter machines: angular momentum conversion by collective modes in optically bound nanoparticle arrays
Abstract
The creation of optically powered self-assembling nano-to-meso-scale machines that do work is a long-standing goal in photonics. We demonstrate an optical matter (OM) machine that converts the spin angular momentum (SAM) of light into orbital angular momentum (OAM) to do mechanical work. The specific OM machine we study is based on a sixfold symmetric hexagonally ordered nanoparticle array that operates as an OM “gear” that is assembled and made to rotate in a circularly polarized Gaussian beam. The rotational symmetry of the OM gear leads to a selection rule for the allowed scattering modes based on their angular momentum. Electrodynamics calculations show that the collective scattering modes with the largest angular momentum scatter strongly in the transverse direction. Simulations and experiments show that the angular momentum that accompanies the scattered light causes a “negative torque” response on the OM gear and drives a “probe” particle placed outside the OM gear around the gear in an asymmetric force field analogously to Brownian ratchets. The gear–probe OM machine concept can be expanded to applications in nanofluidics and particle sorting.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Oct 08, 2020
- Source ID
- 10.1364/optica.396147
Entities
People
- Curtis W Peterson
- J. A. Parker
- Norbert F. Scherer
- Stephen K Gray
- Stuart A. Rice
- Yuval Yifat
- Zijie Yan
Organizations
- Office of Naval Research
- United States Department of Energy
- W. M. Keck Foundation