Preparation and spectroscopy of Yb/sup 2+/ doped fluorides

Summary form only given. Up to now UV solid state lasers are realised on the basis of 5d-4f transitions of Ce/sup 3+/. The aim of the work is the development of a new laser material in the UV and visible spectral range making use of 5d-4f transitions of divalent rare earth. The optical transitions between the 4f/sup n-1/-5d state and the 4f/sup n/ state involve energy levels of different parity and are therefore electric dipole allowed. Thus high transition rates are expected. Furthermore, the strong electron-phonon coupling yields broad emission and excitation bands. In the past, especially Sm/sup 2+/ and Eu/sup 2+/ ions were thoroughly investigated, whereas Tm/sup 2+/ is difficult to stabilise. In the work Yb/sup 2+/ as doping material is the focus of interest. In case of divalent incorporation the 4f-shell is completely filled and as a result no disturbing 4f-4f transitions influences the luminescence due to the 5d-4f transition. Spectroscopic data on Yb/sup 2+/-doped LiCaAlF/sub 6/ (LiCAF) and LiSrAlF/sub 6/ (LiSAF) are presented for the first time.