Dark Mode - Faraday Rotation Synergy for Enhanced Magneto-Optics

摘要

We examine the efficacy of Dark-mode plasmonics as a platform for enhancedmagneto-optics. Dark-mode of a small particle consists of two co-existingequal-intensity and mutually opposing dipolar excitations. Each of these twoopposing dipoles may even resonate at or near the dark-mode frequency, but thenet dipole moment vanishes due to the mutual cancelation between the opposingdipoles. We show that application of external magnetic bias may alleviate theintense destructive interference. Furthermore, under external magnetic bias theopposing dark-resonances of a plasmonic particle shift in opposite directionsand create a region of extremely sensitive Faraday rotation. We show that themagnetized dark resonance in lossless Ag-like particle may provide more than 20degrees rotation under magnetic fields of the order of 1-2 Tesla, exhibitingmagneto-plasmonic activity that is 2-3 orders of magnitude larger than thatobserved in conventional plasmonic particle of the same material.