Regensburg 2013 – scientific programme
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O: Fachverband Oberflächenphysik
O 7: Plasmonics and Nanooptics I
O 7.5: Talk
Monday, March 11, 2013, 11:30–11:45, H31
Nonlinear optical response of complex plasmonic nanoantennas and Fano structures — •Bernd Metzger1, Mario Hentschel1,2, Thorsten Schumacher1,2, and Harald Giessen1 — 14th Physics Institute and Research Center SCoPE, University of Stuttgart, Pfaffenwaldring 57, 70569 Stuttgart, Germany — 2Max Planck Institute for Solid State Research, Heisenbergstr. 1, 70569 Stuttgart, Germany
For the design of optical materials with desired functionality and optical response, we require a deep understanding of the light-matter interaction. In particular plasmonic nanoantennas have shown great potential for tailoring the linear as well as the nonlinear optical response. To gain insight into the nonlinear optical processes that occur upon illumination of these nanoantennas with strong light fields, we perform third harmonic spectroscopy of different complex nanoantenna structures using widely tunable sub-30 fs laser pulses. We find the peak efficiency of the third harmonic emission of rod-type antennas slightly red-shifted to their far-field extinction spectrum. This behavior can be understood and modeled using a classical anharmonic oscillator [1]. Furthermore, we investigate complex nanoantennas, such as dolmen-type and oligomer structures, which exhibit Fano resonances in their linear extinction spectrum. The nonlinear response of these structures is as well strongly related to their linear optical properties and originates mostly from the interplay of bright and dark modes as well as the intense localized near-fields within the metallic nanostructures.
[1] M. Hentschel et al., Nano Lett. 12, 3778 (2012).