Plasmonic enhancement of Faraday rotation with gold nanodisks with low height-to-diameter aspect ratios

We investigate the Faraday rotation induced in gold nanodisks with low height-to-diameter aspect ratios. Through a systematic study, we analyze the phenomenon using electrostatic theory with the modified long-wavelength approximation. We show that the Faraday rotation is enhanced at the localized surface plasmon resonance when the nanodisk’s effective mean free path is equal to the mean free path of the conduction electrons in the bulk metal, where light absorption dominates over light scattering. We also show that the Faraday rotation is largely enhanced at shorter rather than longer wavelengths.