Quenching behaviour of highly doped Yb:YAG and YbAG

In this paper, 80% doped Yb:YAG and YbAG crystals were investigated by means of fluorescence lifetime, optical absorption and photoconductivity measurements in order to study the effect of the Yb/sup 2+/ impurities in the quenching of the /sup 2/F/sub 5/2//spl rarr//sup 2/F/sub 7/2/ Yb/sup 3+/ transition. The samples were grown in rhenium crucibles in order to avoid other impurities like Fe/sup 3+/ in the crystals. Annealed samples (1050/spl deg/C for 7 days) were also studied in order to investigate the properties of the crystals without Yb/sup 2+/.