Name: Dr. Heinz Deters
Diploma / M.Sc degree: Westfälische Wilhelms-Universität Münster, Germany
(March 2008)

PhD Project: Structural elucidation of yttrium-containing laser materials


Abstract of Research Project


In comparison with single crystals, glasses offer considerable compositional flexibility and are able to accommodate and disperse larger quantities of rare-earth (RE) ions. In this manner glasses serve as great hosts for RE ions and are therefore very useful for laser applications. Because the structure of a certain host material, in particular the local environment of the RE ions, has a strong influence on the emission properties, structural information is essential in order to predict the required properties depending on composition.
Usually, solid-state nuclear magnetic resonance (NMR) spectroscopy is used for the structural elucidation of glasses, but unfortunately, the RE species themselves are not directly accessible to solid-state NMR investigations due to their paramagnetism. To get to know the local environment of the RE ions, this problem can be approximated making use of the following strategies:

1. The RE ions can be replaced by diamagnetic mimics having similar ionic radii. These mimics like yttrium can be measured by NMR spectroscopy.
2. Paramagnetic and compositional effects on the NMR-spectra of the glass-forming species (like ¹¹B, ²⁷Al, ³¹P etc. can be considered.
3. Pulsed electron paramagnetic resonance (EPR) spectroscopy, particularly the electron spin echo envelope modulation (ESEEM) technique, is a very promising tool to identify the nuclei within the immediate environments of the paramagnetic dopant ions.