Metasurfaces based on Functional Materials in THz and Optical Regions

Abstract

In this paper we present the properties of metamaterials and metasurfaces composed of resonant micro/nano-structures in which their tunable electromagnetic (EM) properties can be achieved by employing the substrate or resonant structures consisting of functional materials such as polydimethylsiloxane (PDMS), Vanadium-dioxide (VO2), shape memory alloys (SMAs) or in general smart materials. Using a mechanical stretching PDMS substrate for a metasurface, reflectance and transmission of electromagnetic (EM) wave can be remarkably altered. Moreover, by employing resonators consists of Nitinol (NiTi) split ring resonators (SRR) which transforms to complete ring resonator (CRR) thermally, the resonance wavelength and its modal behaviour are affected. Furthermore, the chiroptical activity of planar optical metasurfaces composed of L-shape heterogeneous (Ag-VO2) dimer is studied as well. It is shown that by increasing temperature from room temperature to 81°C, the observed optical activity (OA) at 690 nm has been raised ∼ 50%, because of the occurred phase transition.