Editing Faraday effect (section)

=== Plasmonic and magnetic materials ===
[[File:Optical cavity created by plasmonic materials.png|upright=1.35|thumb|left]]
In 2009 <ref>{{cite journal|last1=Cohen|first1=Adam|title=Surface Plasmon Resonance Enhanced Magneto-optics(SuPREMO): Faraday Rotation Enhancement in Gold-Coated Iron Oxide Nanocrystals|journal=Nano Letters|volume=9|issue=4|pages=1644–1650|doi=10.1021/nl900007k|pmid=19351194|year=2009|bibcode=2009NanoL...9.1644J}}</ref> γ-Fe<sub>2</sub>O<sub>3</sub>-Au core-shell nanostructures were synthesized to integrate  magnetic (γ-Fe<sub>2</sub>O<sub>3</sub>) and plasmonic (Au) properties into one composite. Faraday rotation with and without the plasmonic materials was tested and rotation enhancement under 530&nbsp;nm light irradiation was observed. Researchers claim that the magnitude of the magneto-optical enhancement is governed primarily by the spectral overlap of the magneto-optical transition and the plasmon resonance.

The reported composite magnetic/plasmonic nanostructure can be visualized to be a magnetic particle embedded in a resonant optical cavity. Because of the large density of photon states in the cavity, the interaction between the electromagnetic field of the light and the electronic transitions of the magnetic material is enhanced, resulting in a larger difference between the velocities of the right- and left-hand circularized polarization, therefore enhancing Faraday rotation.