Magneto-optical metasurfaces

Vassilios Kapaklis
Vassilios Kapaklis. Photo: Camilla Thulin.

The Swedish Research Council reached a decision on October 31, 2019 on project grants and starting grants for Natural and Engineering Sciences. The Department of Physics and Astronomy is granted 40 840 000 SEK for the period 2020-2023 for in total nine project grants and three starting grants. The projects will begin during 2020.

Project description

Project title: Magneto-optical metasurfaces
Main applicant: Vassilios Kapaklis, Division of Materials Physics
Grant amount: 3 400 000 SEK for the period 2020-2023
Funder: Project grant from the Swedish Research Council

Metasurfaces are arrays of nanometer-sized islands modulating the behavior of light and shaping optical wavefronts. While the promise of such designer flat optical components is substantial, significant challenges must be overcome if they are to reach their full potential in modern applications. In particular, there is a need for control of their functionality, by enabling dynamical reconfigurability. To address this challenge, we will use magnetism to define a ground-breaking framework for the creation of adaptive and reconfigurable flat optical devices. We will employ a novel class of magnets – two-dimensional lattices of single-domain nano-magnets – as a means to achieve this control. Magneto-static interactions between these nano-magnets, result in a collective magnetic order and dynamics. Furthermore, this order can be controlled and reconfigured, using external stimuli such as magnetic fields, temperature or opto-magnetic effects. The nano-magnet lattice acts as a phase grating for incident light, since magneto-optical effects impose local changes on the polarization and phase of the optical wavefronts across the metasurface. Crucially, this grating structure is defined by the degree and nature of the magnetic order of the nano-magnets. We aim to elucidate the fundamentals of light scattering from magneto-optical metasurfaces, relating it to the magnetic order and dynamics. This framework can be used for the ultimate goal of achieving flat reconfigurable optics.