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Circular Dichroism in Higher‐Order Diffraction Beams from Chiral Quasiplanar Nanostructures
Author(s) -
Kuppe Christian,
Williams Calum,
You Jie,
Collins Joel T.,
Gordeev Sergey N.,
Wilkinson Timothy D.,
Panoiu NicolaeCoriolan,
Valev Ventsislav K.
Publication year - 2018
Publication title -
advanced optical materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.89
H-Index - 91
ISSN - 2195-1071
DOI - 10.1002/adom.201800098
Subject(s) - diffraction , materials science , miniaturization , circular polarization , optics , circular dichroism , wavelength , polarization (electrochemistry) , nanostructure , optoelectronics , nanotechnology , physics , crystallography , chemistry , microstrip
Abstract Miniaturization down to the nanoscale has enabled a new paradigm of ultrathin optical devices, capable of manipulating the direction, polarization, and frequency of light. Great interest is drawn by the promising prospects of deep‐subwavelength material dimensions. However, interesting properties and opportunities offered by structures with sizes comparable to the wavelength of light appear to have been overlooked. Here, quasiplanar chiral arrays made of gold are considered and show that higher‐order diffracted beams can yield extremely large chiroptical responses for optical frequencies. The chosen sample geometry demonstrates spectrally tunable polarization conversion and extremely large circular dichroism. Experimental and numerical data are in good agreement, for both sample chiral forms, and for the complementary geometries under Babinet's principle. Specifically, the experimental results show that the fractional circular dichroism (CD) can be as high as 20%, in the third‐order diffraction beam. Based on the numerical results, a great potential for improvement is anticipated, which makes higher‐order diffraction CD a very promising candidate for ultrathin optical applications.