Berlin 2012 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 34: Poster Session I (Graphene; Plasmonics and nanooptics; Coherence and coherent control in nanophotonics and plasmonics)
O 34.39: Poster
Dienstag, 27. März 2012, 18:15–21:45, Poster E
Ferroelectric-metal core-shell nanoparticles — •Thomas Kämpfe, Philipp Reichenbach, Stefan Grafström, and Lukas M. Eng — Institute of Applied Photophysics, University of Technology Dresden, 01062 Dresden
The optical properties of plasmonic nanoparticles (NPs) are widely used in linear-optical microscopy techniques as well as in many nano-technological applications. However, in coherent nonlinear optical microscopy the narrow adjustment range of the localized surface plasmon (LSP) resonance wavelength practically restricts the application to far-off-resonant excitation, hence dramatically limiting the efficiency of the invoked nonlinear processes.
Here, we show how to increase the nonlinear particle scattering by using dielectric-metallic core-shell NPs. Such a core-shell nanosystem provides plasmon-resonance tuning from the visible into the near-infrared wavelength range, allowing to resonantly excite LSPs with standard femtosecond laser sources. Moreover, a ferroelectric core will give rise to strongly enhanced second-harmonic generation due to the field enhancement produced by the plasmonic shell. We demonstrate (a) the fabrication steps for BaTiO3@Au core-shell NPs, (b) the optically controlled in-situ adjustment of their plasmonic resonance by laser-induced metal precipitation [1], and (c) the ability of such BaTiO3@Au core-shell NPs to emit enhanced SHG. The approach sketched here is very versatile, and paves the way to nonlinear-optical read-out of nearfields by means of a single core-shell NP probe via the emitted second-harmonic radiation.
[1] T.Härtling et.al., Nanotechnology 21, 145309 (2010)