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.

Data-driven reaction coordinate discovery in overdamped and non-conservative systems: application to optical matter structural isomerization

“…The OM system consists of six silver nanoparticles of 150 nm diameter confined to a 2D plane and optically trapped by a circularly polarized focused laser beam, which makes the interactions isotropic in 2D 23 , 25 . The NPs tend to form metastable configurations that, to a first approximation, maximize the number of optical binding electrodynamic interactions, analogous to chemical bonds, with an inter-particle spacing of approximately one optical wavelength 43 .…”

“…A number of methods and tools have been developed to understand the effect of incident field on configurations, stability, and non-conservative dynamics of OM arrays 45 – 47 , including the spin angular momentum of light in optical tweezers used to introduce the driven spin of individual NPs 48 – 52 , and inter-particle electrodynamic interactions that create orbital rotation in OM arrays 23 , 24 , 53 . Therefore, determining the kinetic network and quantifying the effect of these interventions upon OM kinetic networks offers a new route to engineer and control the stability and transitions of particular OM structural isomers with applications in optical matter machines 25 .…”

“…Electrodynamics-Langevin dynamics (EDLD) simulations were performed with the Generalized Multiparticle Mie Theory (GMMT) using the MiePy software developed by the Scherer Lab 25 , 56 . Silver NPs with 150 nm diameter were used as the material constituents of the optical matter configurations.…”

Electric Propulsion Methods for Small Satellites: A Review

“…A recent demonstration of how laser light can manipulate mechanical processes of tiny optical nanomachines could be very advantageous. Potentially actuating parts of the light sail or initiating mechanical processes remotely [120]. Laser driven or beam powered propulsion, which operates over a continuous waveform (CW), is thought to offer a large reduction in cost whilst also greatly increasing the potential velocities due to a continuous acceleration and low mass ratios by not carrying the fuel.…”

Intermodal Brillouin scattering in solid-core photonic crystal fibers

“…In our simulations we employed: S = 2πr c , H = 0.3 µm (wall thickness separating any two holes), h 0 = πr 2 c /S = 0.85 µm, ρ = 2203 kg m −3 from Auld (1973) 3 , M m = 29 kg mol −1 from Lide (2003) 8 , p = 10 5 Pa, and T =300 K.…”