Selective excitation spectra and energy level structure of Dy3+:ThO2 crystal

Dy3+ : ThO2 crystal was grown by the flux technique for the first time. The emission spectra, excitation spectra and fluorescence decay curves were measured and discussed. By using emission spectra obtained under selective dye laser excitation at 12 K, together with the crystal-field theory, the site symmetry of Dy3+ ions in ThO2 was determined as C-3v and its energy level structure was tabulated. The lifetime of radiative level F-4(9/2) was also determined as 0. 40ms.