Dynamic plasmon-empowered electrically controlled metasurfaces

Abstract

Optical metasurfaces (OMSs) represent subwavelength-dense planar arrays of nanostructured elements designed to control local phases and amplitudes of scattered optical fields, thus being able to manipulate radiation wavefronts at a subwavelength scale. In the past decade, many configurations involving different physical mechanisms have been developed, and numerous diverse applications have been demonstrated, including free-space wavefront shaping, versatile polarization transformations, optical vortex generation, optical holography and many others [1]. However, to date, most reported OMSs are static, featuring well-defined optical responses determined by OMS configurations that are set during fabrication, although, for more intelligent and adaptive systems, dynamic OMSs with externally controlled functionalities are in high demand. Realization of dynamic OMSs is, however, very challenging because of the high density of array nm-sized elements that are also arranged in nm-thin planar configurations, circumstances that limit severely the interaction volumes. In this talk, I present recent results that we obtained with two different configurations for realizing electrically controlled OMSs operating in reflection: piezoelectric micro-electro-mechanical systems (MEMS) integrated with gap surface-plasmon (GSP) based OMSs [2] and FabryPerot resonators based on thin electro-optic crystal layers sandwiched between nanostructured electrodes [3]. Their operational principles are described, and the main experimental results obtained are presented. Furthermore, new developments and functionalities demonstrated will be presented at the conference.