Regensburg 2016 – scientific programme

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O: Fachverband Oberflächenphysik

O 52: Photonics and Nanooptics II: Nonlinear Response

O 52.7: Talk

Wednesday, March 9, 2016, 12:00–12:15, S051

Nonlinear Refractory Plasmonics with TiN Nanoantennas — •Lili Gui, Xinghui Yin, Mario Hentschel, and Harald Giessen — 4th Physics Institute and Research Center SCoPE, University of Stuttgart, 70569 Stuttgart, Germany

Optical activity exists generally in nature, as many biomolecules such as proteins are chiral. Chiral plasmonic nanostructures are highly interesting since they are potentially ideal and sensitive platforms for biosensing due to the strong superchiral near fields and their own giant chiroptical effects. Exploration of nonlinear chiroptical effects in chiral plasmonic structures is even more desired since the nonlinear chiroptical effects are typically orders of magnitude higher than the linear optical counterparts. Here we study the third-order nonlinear chiroptical effects of 3D chiral structures consisting of corner-stacked gold nanorods. Compared to second-order effects, third-order effects are more immune to fabrication defects and surface roughness. We experimentally investigate the third-harmonic spectroscopy with left- and right-circularly polarized fundamental light, respectively. The third-order chiroptical responses can be well understood when we utilize a coupled anharmonic oscillator model considering the phase retardation of light interaction with the 3D gold nanorods. This model is instructive to guide a practical design of plasmonic chiral structures for a giant third-harmonic-generation circular dichroism (THG-CD) effect.