Giant circular dichroism induced by silver nanocuboid heterodimers

Metallic nanocuboid heterodimers are proposed to generate a giant circular dichroism (CD) effect. Two cuboids in the heterodimers have different heights. The dipole and quadrupole charge oscillation modes in the cuboids occur under left-and right-handed circular polarizations. The height difference generates phase difference between charge oscillations in the two cuboids. The two charge oscillations and the phase difference between them are consistent with the Born-Kuhn model for the CD effect. The CD effect of the nanocuboid heterodimers can be tuned by changing the structural parameters of the nanocuboid heterodimers, especially the height difference between two cuboids. The results of this research are not only useful for designing plasmonic structures to generate the CD effect but also for understanding the physical mechanisms of the CD effect. (C) 2015 Optical Society of America