Enhancement of Optical Magnetic Modes by Controlling the Handedness of Symmetry Breaking in Fano Metamolecules

Artificial plasmonic magnetic metamaterials consisting of closely spaced metallic nanoparticles have been extensively investigated in recent years. In this paper, a novel approach to enhancing the optical magnetic mode in a nanoquadrumer Fano metamolecule by controlling the handedness of symmetry breaking under linearly polarized illumination is proposed. Circular dichroism of the asymmetrical metamolecule under circularly polarized illumination can also be generated. The results are analyzed using coupled-mode theory. This paper will be of benefit to artificial magnetism design, negative permeability metamaterial engineering, and optical activity tuning.