Berlin 2015 – wissenschaftliches Programm

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DF: Fachverband Dielektrische Festkörper

DF 11: Small Polarons in LiNbO₃

DF 11.5: Poster

Mittwoch, 18. März 2015, 11:20–11:20, EB 133C

Polar niobate-nanocrystals: Synthesis and nonlinear optical analysis — •Anke Düttmann¹, Christian Kijatkin¹, Karsten Kömpe², Javid Shirdel¹, and Mirco Imlau¹ — ¹Dept. of Physics, Osnabrueck University, D-49069 Osnabrueck — ²Instit. of Chemistry, Osnabrueck University, D-49076 Osnabrueck

Niobate-nanocrystals can be used as light emitters on the nanoscale by means of second harmonic generation (SHG). They are of interest as markers in high-resolution nonlinear optical microscopes for cell biology and tumor visualization as they offer a tremendeous contrast in comparison to fluorescent markers. Although, however, the growth of KNbO₃ or LiNbO₃ single crystals is well established, almost nothing is known about respective nanocrystals synthesis with homogeneous size distribution and diameters in the range from 5-50 nm. In this contribution, we present our results on size-controlled synthesis of niobate-nanocrystals and their nonlinear optical analysis by means of SHG-microscopy. By choosing suitable oxidic precursors and their stabilization, we succeeded in a targeted synthesis of KNbO₃ and NaNbO₃ (20 - 80 nm). The dispersion properties of the SHG signal verify the polar nature of the nanocrystals and the possibility to induce a polarization wave in crystals with diameters smaller than the wavelength. Studies as a function of nanocrystal diameter follow the behavior expected from coupled wave theory such that signals detection of particles below 10 nm becomes possible. Financial support by the DFG (INST 190/165-1 FUGG) is gratefully acknowledged.