Thermally-controlled magnetooptical metasurface for tunable Faraday rotation

Abstract

We present novel type of tunable magneto-optical metasurfaces performing Faraday rotation, the sign and value of which are not fixed after the structure fabrication but can be tuned in a wide range via heating of the metasurface. We demonstrate both experimentally and theoretically that the Faraday rotation angle is enhanced in the vicinity of the magnetodipole and electrodipole Mie resonances and can be changed in a wide range from -0.3 degrees to +0.1 degrees for the same metasurface at fixed wavelength of incident light under the temperature changes from the 294~K to 488~K. Such thermal heating can be performed by an external control laser. As laser radiation can be focused at the spots of $~\sim 1\mu$m diameter, the magneto-optical response can also be tuned locally. Thus one may obtain the inhomogeneous magnetooptically-induced polarization rotation distributions across the metasurface by the creation of the laser beam patterns with the desired intensity profiles. Another possibility opened by the proposed merasurface is self-modulation of polarization of laser light performed depending on its intensity.