Engineering Fano-Resonant Hybrid Metastructures with Ultra-High Sensing Performances

Metamaterials-based sensors are of primary interest in physics, materials science, medicine, and biophysics thanks to their ability to detect very tiny amount of molecules spread into a medium. Here, a metastructure utilizing the epsilon near zero (εNZ) and Fano–Rabi physics is engineered to design a system with ultra-high sensitivity. So far, a dedicated study of such systems has been missing. In this work, the authors report the results of their efforts to fill the gap by considering a metasurface, designed as a periodical array of rings with a cross in their center, placed on top of a silver (Ag) and zinc oxide (ZnO) epsilon near-zero optical nanocavity (εNZ-ONC) metamaterial. The accurate selection of the metasurface parameters allows the design of a sensor exhibiting an extremely high sensitivity of about 16 000 and 21 000 nm RIU−1 depending on incoming polarization. This work paves the way for the development of novel groundbreaking devices for biomedical and environmental application based on plasmonic and photonic design principles.