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Main Authors: Engay, Einstom, Shanei, Mahdi, Mylnikov, Vasilii, Wang, Gan, Johansson, Peter, Volpe, Giovanni, Käll, Mikael
Format: Preprint
Published: 2024
Subjects:
Online Access:https://arxiv.org/abs/2406.11489
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author Engay, Einstom
Shanei, Mahdi
Mylnikov, Vasilii
Wang, Gan
Johansson, Peter
Volpe, Giovanni
Käll, Mikael
author_facet Engay, Einstom
Shanei, Mahdi
Mylnikov, Vasilii
Wang, Gan
Johansson, Peter
Volpe, Giovanni
Käll, Mikael
contents Nanostructured dielectric metasurfaces offer unprecedented opportunities to control light-matter momentum exchange, and thereby the forces and torques that light can exert on matter. Here we introduce optical metasurfaces as components of ultracompact untethered microscopic metaspinners capable of efficient light-induced rotation in a liquid environment. Illuminated by weakly focused light, a metaspinner generates torque via photon recoil through the metasurfaces ability to bend light towards high angles despite their sub-wavelength thickness, thereby creating orbital angular momentum. We find that a metaspinner is subject to an anomalous transverse lateral optical gradient force that acts in concert with the classical gradient force. Consequently, when two or more metaspinners are trapped together in a laser beam, they collectively orbit the optical axis in the opposite direction to their spinning motion, in stark contrast to rotors coupled through hydrodynamic or mechanical interactions. The metaspinners delineated herein not only serve to illustrate the vast possibilities of utilizing optical metasurfaces for fundamental exploration of optical torques, but they also represent potential building-blocks of artificial active matter systems, light-driven micromachinery, and general-purpose optomechanical devices.
format Preprint
id arxiv_https___arxiv_org_abs_2406_11489
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Transverse optical gradient force in untethered rotating metaspinners
Engay, Einstom
Shanei, Mahdi
Mylnikov, Vasilii
Wang, Gan
Johansson, Peter
Volpe, Giovanni
Käll, Mikael
Optics
Nanostructured dielectric metasurfaces offer unprecedented opportunities to control light-matter momentum exchange, and thereby the forces and torques that light can exert on matter. Here we introduce optical metasurfaces as components of ultracompact untethered microscopic metaspinners capable of efficient light-induced rotation in a liquid environment. Illuminated by weakly focused light, a metaspinner generates torque via photon recoil through the metasurfaces ability to bend light towards high angles despite their sub-wavelength thickness, thereby creating orbital angular momentum. We find that a metaspinner is subject to an anomalous transverse lateral optical gradient force that acts in concert with the classical gradient force. Consequently, when two or more metaspinners are trapped together in a laser beam, they collectively orbit the optical axis in the opposite direction to their spinning motion, in stark contrast to rotors coupled through hydrodynamic or mechanical interactions. The metaspinners delineated herein not only serve to illustrate the vast possibilities of utilizing optical metasurfaces for fundamental exploration of optical torques, but they also represent potential building-blocks of artificial active matter systems, light-driven micromachinery, and general-purpose optomechanical devices.
title Transverse optical gradient force in untethered rotating metaspinners
topic Optics
url https://arxiv.org/abs/2406.11489