Regensburg 2010 – wissenschaftliches Programm

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DF: Fachverband Dielektrische Festkörper

DF 15: Optical and nonlinear optical properties, photonics II

DF 15.3: Vortrag

Donnerstag, 25. März 2010, 11:05–11:25, H11

Investigation of nonlinear optical effects in strontium barium niobate — •Alexander Niemer, Rainer Pankrath, and Klaus Betzler — University of Osnabrück, Department of Physics, Barbarastr. 7, 49076 Osnabrück

The ferroelectric relaxor and optical nonlinear material strontium barium niobate (SBN) shows some very interesting effects in the nonlinear generation of light and offers the possibility to study the interaction between the luminescence of rare earth ions and the nonlinear processes.

The possibility of getting radially polarized light from an SBN crystal is investigated. By excitation with an optical parametrical oscillator radially polarized white light can be generated. In the literature [1] it is shown, that such light can be focused to a smaller spot size than linear or azimutal polarized light. At the moment an about 10% smaller spot size is realized.

Further the luminescence from different rare earth impurities is studied. To understand the processes which are responsible for the upconversion the dependency of time and excitation energy was investigated. For erbium and ytterbium an anomalous dependency of the fluorescence decay time on the dopant concentration is found. Because ytterbium doped SBN shows a very high luminescence intensity the luminescence light could be used for other nonlinear processes like, e.g. sum frequency generation.

[1] R. Dorn, S. Quabis, G. Leuchs: Optics Communications 179, 1-7 (2000)