Berlin 2015 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 50: Coupled Nanostructures and Light Localization
O 50.5: Vortrag
Mittwoch, 18. März 2015, 11:30–11:45, MA 043
Simple plasmonic design for homogeneous chiral near-fields — •Martin Schäferling1, Nader Engheta2, Thomas Weiss1, and Harald Giessen1 — 14th Physics Institute and Research Centers SCoPE and SimTech, University of Stuttgart, Germany — 2Department of Electrical and Systems Engineering, University of Pennsylvania, Philadelphia, USA
Chiroptical spectroscopy utilizes chiral electromagnetic fields to probe the handedness of natural chiral molecules. The strength of the chiroptical interaction can be quantified by the so-called optical chirality, which is a property of the electromagnetic field [1].
Plasmonic nanostructures can tailor the optical chirality of their near-fields [2]. We have shown recently that geometrically chiral nanostructures can lead to strong chiral fields over an extended region [3]. However, our proposed design of four intertwined helices is difficult to fabricate and therefore not the optimum for potential applications.
In this contribution, we present a novel design combining a layer of diagonal slits with a mirror for the generation of chiral near-fields. The design is easy to fabricate by electron-beam lithography. Access to the chiral near-fields is straightforward. Although the optical chirality is weaker than for helices, our structure might be preferable for applications due to its simplicity. We examine the strength and shape of the generated chiral near-fields and discuss optimization strategies.
[1] Y. Tang and A. E. Cohen, Science 332, 333 (2011).
[2] M. Schäferling et al., Phys. Rev. X 2, 031010 (2012).
[3] M. Schäferling et al., ACS Photonics 1, 530 (2014).