Chiral plasmonic nanomaterials present preferential interactions with circularly polarized lights originated from their geometries in mirror. Recently substantial efforts have been made in the area of synthesis of such materials, however understanding of chiroptical responses from these complicated structures were not fully understood yet. In this work, we examined the model structures with helical arrays of plasmonic nanoparticles with presence of anisotropic nanopillars at center. In previous studies, the anisotropy of nanopillars was typically ignored due to complexity. We investigated the chiroptical responses of such models with variance of anisotropy in nanopilllars based on the calculation via finite elements method (FEM). The results show that the anisotropy of center nanopillar can have significant effects on the chiroptical response of overall chiral nanostructure. Calculated circular dichroism (CD) spectra can be changed into opposite sign in the specific conditions of negative birefringence. In addition, we could observe that, when refractive index of anisotropic pillars are large enough &gt; 2.5, the chiroptical responses can be significantly enhanced by 17 times in maximum. At last, the optical properties of surrounding media can effectively shift the peak positions and the magnitudes in the CD spectra. Our calculations show the significance of anisotropy, which has not been conceived as important parameters. We believe that this work will deepen the understanding of chiroptical responses in the area of chiral nanomaterials and further will help to pave the way toward various applications such as optical devices, biosensors, and chiral catalysis.

Chiroptical responses of helical arrays of plasmonic nanoparticles around anisotropic nanopillars

253rd National Meeting (2017)

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