New Trends in Optical Resonant Bio-Chemical Sensing

The development of innovative bio-chemical sensors is of great importance to make new devices available to the market. In the current paper, we review recent trends on optical resonant sensors that may involve plasmonic or geometrical resonances. In all cases, resonance is activated by excitation with electromagnetic light of proper wavelength. Plasmonic hot electrons, obtained by shining light on metal nanoparticle decorated metal oxides, can bring new effects in physicochemical processes, affecting electrical and optical properties (absorption/transmission, Surface Enhanced Raman Spectroscopy SERS). Geometrical resonances are involved in Mie and Whispering Gallery Modes (WGM) based sensing, including metasurfaces for optical detection of molecules and nonlinear effects in metamaterials.