Effects of Silicon Dioxide on Structure and Spectroscopic Properties of Neodymium Doped Calcium Aluminate Glass

Nd3+-doped calcium-aluminate glasses with different contents of Si O2 were prepared by conventional melting method. The change of glasses structures were studied by Raman spectroscope. The non-bridging oxygens(NBOs) around Si4+ ions increase at higher Si O2 content samples which are transferred from alumina tetrahedron lattices and a more polymerization Al-O network appears in glass structure due to lower NBOs content. From the absorption spectra, J-O strength parameters(?), spontaneous transition probabilities(Arad), branching ratios(β), emission cross-sections(σe), and radiative life(τrad) were evaluated by Judd-Ofelt theory. Analysis on the evaluation result and fluorescence spectra reveal that the surrounding structure symmetry of Nd3+ ions is ameliorated and the full width at half maximum(FWHM) of emission peak at 1067 nm is narrowed, meanwhile the emission cross-sections is enlarged gradually with the Si O2 content increasing. These results show that Nd3+-doped calcium aluminate glass containing low content of Si O2 has potential applications in ultrashort-pulse laser materials.