Optical coupling between resonant dielectric nanoparticles and dielectric waveguides probed by third harmonic generation microscopy

Abstract

We report on the observation of optical coupling between a Mie-resonant subwavelength silicon nanodisk and a silicon waveguide, revealed through third harmonic generation microscopy. Changing the gap between the nanodisk and the waveguide, we observe third harmonic intensity modulation of up to 4.5. We attribute this strong modulation to modifications of the magnetic dipole resonance and local electric fields inside the nanodisk, as supported by full-wave simulations.