Regensburg 2016 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 10: Plasmonics and Nanooptics: Light-Matter Interaction
HL 10.6: Vortrag
Montag, 7. März 2016, 12:00–12:15, S054
Enantiomorphic chiral near-fields in locally chiral plasmonic lattices — •Martin Schäferling, Xinghui Yin, Maxim Nesterov, Harald Giessen, and Thomas Weiss — 4th Physics Institute and Research Centers SCoPE and SimTech, University of Stuttgart, Germany
Chiral near-fields, which interact strongly with chiral molecules, can be obtained by illuminating geometrically chiral plasmonic nanostructures with circularly polarized light [1,2]. Fields with opposite handedness can be used to probe the chiroptical properties of chiral molecules with enhanced sensitivity. However, the field pairs generated by periodic arrangements of chiral nanostructures are, in general, not enantiomorphic. Additionally, such structures exhibit a chiroptical far-field response even in absence of chiral probe molecules. Both effects hamper the implementation of plasmonically enhanced chiroptical spectroscopy schemes.
In this contribution, we discuss periodic arrangements of simple achiral building blocks where the resulting superstructure is geometrically achiral, but still provides left- and right-handed geometrically chiral substructures. Due to their symmetry, such configurations provide enantiomorphic chiral near-fields, but no chiroptical far-field response. We show how to identify all such arrangements of plasmonic nanodiscs in a 4×4 unit cell that additionally provide C4 symmetry and compare the simulated chiroptical near-field response of selected examples.
[1] Y. Tang and A. E. Cohen, Science 332, 333 (2011).
[2] M. Schäferling et al., Phys. Rev. X 2, 031010 (2012).