Plasmon-mediated magneto-optical transparency

TLDR

Magnetic field control of light enables rapid modulation of intensity and polarization, and nanostructured hybrid materials amplify magneto‑optical effects, yet only enhancement of existing effects has been shown to date. The study proposes a new magneto‑optical effect arising from a specially designed magneto‑plasmonic crystal. In the crystal, incident light excites coupled plasmonic and waveguide modes, and an in‑plane magnetic field activates an orthogonally polarized waveguide mode that alters the spectrum and boosts transparency. Experimentally, the effect achieves 24 % light‑intensity modulation, can potentially exceed 100 %, and enables magnetic‑field control of waveguide modes, highlighting its significance for applied nanophotonics.

Abstract

Magnetic field control of light is among the most intriguing methods for modulation of light intensity and polarization on sub-nanosecond timescales. The implementation in nanostructured hybrid materials provides a remarkable increase of magneto-optical effects. However, so far only the enhancement of already known effects has been demonstrated in such materials. Here we postulate a novel magneto-optical phenomenon that originates solely from suitably designed nanostructured metal-dielectric material, the so-called magneto-plasmonic crystal. In this material, an incident light excites coupled plasmonic oscillations and a waveguide mode. An in-plane magnetic field allows excitation of an orthogonally polarized waveguide mode that modifies optical spectrum of the magneto-plasmonic crystal and increases its transparency. The experimentally achieved light intensity modulation reaches 24%. As the effect can potentially exceed 100%, it may have great importance for applied nanophotonics. Further, the effect allows manipulating and exciting waveguide modes by a magnetic field and light of proper polarization.