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Department of Physics

Dr. Norbert Scherer
University of Chicago, Department of Chemistry
Norbert Scherer
Reactive Optical Matter: non-reciprocal force-powered nano-swimmers and negative optical torque

102 Cardwell Hall
April 2, 2018
4:15 p.m. 

Remarkable collective properties that are found in nature, e.g., fish schooling, bird flocking, and other novel behaviors have been realized in Active Matter systems. The dynamics require consumption of energy to induce motility and interactions (e.g. hydrodynamic, magnetic) that together can give rise to emergent behavior of a collection. This talk will discuss analogous and novel phenomena that occur in collections of (plasmic) nanoparticles in spatially shaped optical beams. The constituents interact electrodynamically by scattering light and thereby create their own interaction potentials that are many body in nature. Broken symmetries in these interactions can lead to non-reciprocal forces of the collection resulting in directed motions. These behaviors are in apparent violation of Newton's Actio et Reactio principle; net translational or rotational motion in contradiction with the properties of the incident field; i.e., angular motion opposite to the handedness of circular polarization or translational motion transverse to the Poynting vector of the optical beams. The origins of these effects will be discussed using electrodynamics simulations and explicit theory.