Regensburg 2010 – scientific programme
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O: Fachverband Oberflächenphysik
O 83: Plasmonics and Nanooptics VII
O 83.1: Talk
Friday, March 26, 2010, 11:15–11:30, H32
Metamaterial sensor for glucose and molecular monolayers using the plasmonic analog of EIT — •Martin Mesch1, Na Liu1, Thomas Weiss1, Carsten Sönnichsen2, and Harald Giessen1 — 14th Physics Institute, University of Stuttgart, Germany — 2Institute of Physical Chemistry, University of Mainz, Germany
We utilize the plasmonic analog[1] of electromagnetically induced transparency (EIT) to construct an optical LSPR (localized surface plasmon resonance) sensor. A combination of stacked gold dipole and quadrupole antennas exhibits a sharp spectral resonance, which shifts for changes in the structures' dielectric environment. To characterize the sensor, aqueous glucose solutions with concentrations between 0% and 25% have been measured in a custom flow cell by Fourier transform infrared spectroscopy. The results reveal a sensitivity of 374 nm per refractive index unit, corresponding to a figure of merit (sensitivity/linewidth) of 4.1. We compare our measurements to S-matrix simulations and give a recipe to determine the most sensitive structure geometry. To our knowledge, this is up to date the most sensitive lithographically manufactured LSPR sensor design. Additional experiments demonstrate the ability to detect a single molecular layer of biotin/streptavidin. [1] N. Liu et al., Nature Materials 8, 758 (2009)