Chiral Metamaterials of Plasmonic Slanted Nanoapertures with Symmetry Breaking
We propose a universal design scheme for a new type of chiral metamaterials based on plasmonic slanted nanoapertures simply milled in a single metal layer. Strong optical chirality is introduced by tilting nanoapertures with almost arbitrary shape along a certain direction to break all the mirror symmetries. As a typical example, chiral metamaterial based on slanted split-ring apertures is demonstrated with giant circular dichroism in transmission (CDT) over 78% at 760 nm. We reveal that the high CDT originates from the circularly dichroic mode coupling process in the slanted nanoapertures induced by spin-dependent field overlap conditions. Furthermore, tunable CDT is presented through the in-plane rotation of nanoapertures to form chiral images with controllable image contrast. Besides, chiral metamaterials with slanted nanoapertures of two other shapes including L-shaped aperture and rectangular aperture are also presented with large circular dichroism. We envision that our demonstrated chiral metamaterials enable promising platforms for a variety of applications in nonlinear optics, chiral imaging and sensing, spectroscopy, and polarization manipulation.
Y. Chen et al., "Chiral Metamaterials of Plasmonic Slanted Nanoapertures with Symmetry Breaking," Nano Letters, vol. 18, no. 1, pp. 520-527, American Chemical Society (ACS), Jan 2018.
The definitive version is available at https://doi.org/10.1021/acs.nanolett.7b04515
Mechanical and Aerospace Engineering
Intelligent Systems Center
Keywords and Phrases
Dichroism; Nonlinear optics; Optical design; Plasmons; Surface plasmon resonance; 3D fabrication; Chiral metamaterials; Mode coupling; Plasmonics; Rectangular aperture; Single metal layers; Symmetry-breaking; Metamaterials; Circular dichroism
International Standard Serial Number (ISSN)
Article - Journal
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