Dresden 2011 – wissenschaftliches Programm
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DF: Fachverband Dielektrische Festkörper
DF 12: Poster
DF 12.10: Poster
Mittwoch, 16. März 2011, 15:00–17:30, P1
Photostable imaging by second-harmonic-generating nanoparticles — •Thomas Kämpfe, Philipp Reichenbach, Stefan Grafström, and Lukas M. Eng — Institute for Applied Photophysics, University of Technology Dresden, 01062 Dresden
Fluorescence microscopy is a widespread and elaborate method in imaging.
However, in practice several disadvantages, most notably bleaching and blinking,
can be observed. Second-harmonic generation (SHG) in noncentrosymmetric nanocrystals with
diameters up to 100 nm seem to be a promising alternative. These particles circumvent the
mentioned constraints as no real transition is invoked and thereby no phototoxic or dark state can be excited.
Long-time stability as well as sufficient signal strength for standard microscopy techniques was obtained for barium titanate
nanoparticles with tetragonal crystal structure. The SHG signal increases quadratically with the
excitation intensity (typ. 10 9 W/cm2); these nanoparticles outshine all fluorescent
markers at dye saturation. Moreover, the emitted second-harmonic radiation is spectrally sharp (∼6 nm)
so that the signal-to-noise ratio can be augmented by means of narrow bandpass filters.
We present the experimental results on the nonlinear optical properties of single BaTiO3 nanoparticles including the
dependence on intensity, excitation wavelength and in-plane polarization as well as obtain the according crystal axis theoretically.