Multipolar Effects in the Optical Active Second Harmonic Generation from Sawtooth Chiral Metamaterials

• DOI: 10.1038/srep22061
• Publication Date: 2016-02-25T10:43:47Z
• Authors: Huimin Su; Yuxiang Guo; Wensheng Gao; Jie Ma; Yongchun Zhong; Wing Yim Tam; C. T. Chan; Kam Sing Wong
• Keywords: Sawtooth wave; Chirality; Planar chirality

Abstract Based on the facts that chiral molecules response differently to left- and right-handed circular polarized light, chiroptical effects are widely employed for determining structure chirality, detecting enantiomeric excess, or controlling chemical reactions of molecules. Compared those in natural materials, behaviors can be significantly amplified plasmonic metamaterials due concentrated local fields structure. The on-going research towards giant metamaterial generally focus optimizing field-enhancement effects. However, observed rely more complicated factors various possibilities remains unexplored. Here we study optical-active second harmonic generation (SHG) a pair planar sawtooth gratings with mirror-imaged patterns. Significant multipolar were polarization-dependent SHG curves. We show chirality nanostructure not only give rise nonzero susceptibility tensor components within electric-dipole approximation, but also lead different levels interactions two orthogonal polarizations further enhance nonlinear optical activity material. Our results thus indicate novel ways optimize structures achieve via interactions.