Regensburg 2016 – scientific programme
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O: Fachverband Oberflächenphysik
O 52: Photonics and Nanooptics II: Nonlinear Response
O 52.1: Talk
Wednesday, March 9, 2016, 10:30–10:45, S051
Nonlinear Plasmonic Sensing — •Martin Mesch, Bernd Metzger, Mario Hentschel, and Harald Giessen — 4th Physics Institute and Research Center SCoPE, University of Stuttgart, Germany
We introduce the concept of nonlinear plasmonic sensing, relying on third harmonic generation from simple plasmonic nanoantennas. Due to the nonlinear conversion process we observe a larger sensitivity upon a local change in the refractive index as compared to the commonly used linear localized surface plasmon resonance sensing. Refractive index changes as small as 10−3 can be detected. In order to determine the spectral position of highest sensitivity, we perform linear and third harmonic spectroscopy on plasmonic nanoantenna arrays, which are the fundamental building blocks of our sensor. Furthermore, simultaneous detection of linear and nonlinear signals allows quantitative comparison of both methods, providing further insight into the working principle of our sensor. While the signal-to-noise ratio is comparable, nonlinear sensing gives about seven times higher signal levels. Our scheme can be extended to other nonlinear processes such as second harmonic generation and sum frequency generation. This opens a new avenue in plasmonic sensing.