Dresden 2014 – scientific programme

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O: Fachverband Oberflächenphysik

O 79: Plasmonics and Nanooptics IV

O 79.3: Talk

Thursday, April 3, 2014, 16:30–16:45, TRE Ma

Chiral Plasmonic Fano Resonance — •Xinghui Yin, Martin Schäferling, and Harald Giessen — 4. Physikalisches Institut, Universität Stuttgart, Pfaffenwaldring 57, 70550 Stuttgart

Chiral plasmonic structures are able to enhance the sensitivity in chiroptical spectroscopy methods. They provide superchiral fields that interact strongly with chiral molecular environments on the nanoscale. [1] At the same time, their inherent chiral spectral features are modified by such an interaction and thus serve as probes that can be readily accessed in far-field measurements. [2] From conventional refractive index based plasmonic sensors, it is known that their sensitivity is maximal for geometries that exhibit a Fano-dip. [3] Prominent examples are plasmonic oligomers with the pentamer as a special C4-symmetric case. Here, we show that stacking two Pentamers on top of each other with a relative rotation angle of 22.5° about the center particle, translates the sharp Fano feature into the circular dichroism spectrum of the thus created three-dimensional chiral plasmonic oligomer. Assessing the electromagnetic properties of the structure reveals that it additionally provides strong superchiral fields, rendering it the ideal candidate for highly-sensitive enhanced chiroptical spectroscopy.

[1] Y. Tang and A. E. Cohen, Science 332, 333 (2011).

[2] E. Hendry et al., Nature Nanotechnology 5 (11), 783 (2010).

[3] B. Gallinet et al., ACS Nano 7, 6978 (2013).