Refractive index sensing with localized plasmonic resonances

The book explores the sensing capabilities of plasmonic resonators in response to changes in the surrounding refractive index. It presents a comprehensive theory that links the resonators' electrodynamic properties, such as resonance wavelength and electric field distribution, to their sensitivity. A figure of merit (FOM) is introduced, accounting for noise and determining the measurability of refractive index changes. Theoretical bounds and scalings in the quasi-static limit are derived, supported by numerical calculations and experiments with crescent-shaped resonators, demonstrating strong alignment with the theory.