Please use this identifier to cite or link to this item: http://hdl.handle.net/1783.1/77314

Multipolar effects in the optical active second harmonic generation from sawtooth chiral metamaterials

Authors Su, Huimin HKUST affiliated (currently or previously).
Guo, Yuxiang HKUST affiliated (currently or previously).
Gao, Wensheng HKUST affiliated (currently or previously).
Ma, Jie
Zhong, Yongchun
Tam, Wing Yim View this author's profile
Chan, Che Ting View this author's profile
Wong, Kam Sing View this author's profile
Issue Date 2016
Source Scientific Reports , v. 6, February 2016, article number 22061
Summary 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 to those in natural materials, chiroptical behaviors can be significantly amplified in chiral plasmonic metamaterials due to the concentrated local fields in the structure. The on-going research towards giant chiroptical effects in metamaterial generally focus on optimizing the field-enhancement effects. However, the observed chiroptical effects in metamaterials rely on more complicated factors and various possibilities towards giant chiroptical effects remains unexplored. Here we study the optical-active second harmonic generation (SHG) behaviors in a pair of planar sawtooth gratings with mirror-imaged patterns. Significant multipolar effects were observed in the polarization-dependent SHG curves. We show that the chirality of the nanostructure not only give rise to nonzero chiral susceptibility tensor components within the electric-dipole approximation, but also lead to different levels of multipolar interactions for the two orthogonal circular polarizations that further enhance the nonlinear optical activity of the material. Our results thus indicate novel ways to optimize nonlinear plasmonic structures and achieve giant chiroptical response via multipolar interactions.
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ISSN 2045-2322
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Language English
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