title: Tailorable chiroptical activity of metallic nanospiral arrays.
abstract: The engineering of the chiroptical activity of the emerging chiral metamaterial, metallic nanospirals, is in its infancy. We utilize glancing angle deposition (GLAD) to facilely sculpture the helical structure of silver nanospirals (AgNSs), so that the scope of chiroptical engineering factors is broadened to include the spiral growth of homochiral AgNSs, the combination of left- and right-handed helical chirality to create heterochiral AgNSs, and the coil-axis alignment of the heterochiral AgNSs. It leads to flexible control over the chiroptical activity of AgNS arrays with respect to the sign, resonance wavelength and amplitude of circular dichroism (CD) in the UV and visible regime. The UV chiroptical mode has a distinct response from the visible mode. Finite element simulation together with LC circuit theory illustrates that the UV irradiation is mainly adsorbed in the metal and the visible is preferentially scattered by the AgNSs, accounting for the wavelength-related chiroptical distinction. This work contributes to broadening the horizons in understanding and engineering chiroptical responses, primarily desired for developing a wide range of potential chiroplasmonic applications.
authors.affiliation: Department of Physics, Hong Kong Baptist University (HKBU), Kowloon Tong, Kowloon, Hong Kong SAR, P. R. China. zfhuang@hkbu.edu.hk and HKBU Institute of Research and Continuing Education, 9F, the Industrialization Complex of Shenzhen Virtual University Park, No. 2 Yuexing 3rd Road, South Zone, Hi-tech Industrial Park, Nanshan District, Shenzhen, Guangdong Province, P. R. China.
authors.forename: Junhong
authors.initials: J
authors.lastname: Deng
authors.affiliation: Department of Physics, Hong Kong Baptist University (HKBU), Kowloon Tong, Kowloon, Hong Kong SAR, P. R. China. zfhuang@hkbu.edu.hk.
authors.forename: Junxue
authors.initials: J
authors.lastname: Fu
authors.affiliation: Department of Physics, Hong Kong Baptist University (HKBU), Kowloon Tong, Kowloon, Hong Kong SAR, P. R. China. zfhuang@hkbu.edu.hk and Institute of Computational and Theoretical Studies, HKBU, Kowloon Tong, Kowloon, Hong Kong SAR, P. R. China and Institute of Advanced Materials, HKBU, Kowloon Tong, Kowloon, Hong Kong SAR, P. R. China.
authors.forename: Jack
authors.initials: J
authors.lastname: Ng
authors.affiliation: Department of Physics, Hong Kong Baptist University (HKBU), Kowloon Tong, Kowloon, Hong Kong SAR, P. R. China. zfhuang@hkbu.edu.hk and HKBU Institute of Research and Continuing Education, 9F, the Industrialization Complex of Shenzhen Virtual University Park, No. 2 Yuexing 3rd Road, South Zone, Hi-tech Industrial Park, Nanshan District, Shenzhen, Guangdong Province, P. R. China and Institute of Advanced Materials, HKBU, Kowloon Tong, Kowloon, Hong Kong SAR, P. R. China and Partner State Key Laboratory of Environmental and Biological Analysis, HKBU, Kowloon Tong, Kowloon, HongKong SAR, P. R. China.
authors.forename: Zhifeng
authors.initials: Z
authors.lastname: Huang