Ultra-high figure-of-merit dielectric metasurface

Abstract

Metamaterials are the sub-wavelength arrays of the composite structure made of metallic and/or dielectric materials. The metal-dielectric structure provides a significant enhancement in the field but has a high loss, low Q-Factor and poor spectral contrast in the visible and infrared frequencies. To overcome these problems, all-dielectric metamaterials structures are the better alternative which offers negligible losses due to their low absorption and hence they have narrow resonance peak and high spectral contrast. When all-dielectric metamaterial with specific geometry (asymmetric oscillators) interacts with the electromagnetic field in visible and infrared (IR) wavelength range, the interaction produces the Fano-Resonance. The Fano resonance depends on the shape and size of the metasurface structure and the refractive index of the surrounding. The Fano-resonance based on all-dielectric metamaterials can be used as a refractive index sensor for biomedical sensing and optical modulation in telecommunication. All-dielectric metamaterials based on Fano resonance can be utilized to have a high Figure-of-merit (FoM) refractive index sensor device. In this work, we are proposing a Fano resonance-based refractive index (RI) sensor which has a high FoM of the order of 2465.