Thermal lens study of energy transfer in Yb(3+)/Tm(3+)-co-doped glasses.

Energy transfer (ET) and heat generation processes in Yb(3+)/Tm(3+)-co-doped low-silica calcium-aluminosilicate glasses were investigated using thermal lens and photoluminescence measurements. Stepwise ET processes from Yb(3+) to Tm(3+), with excitation at 0.976 mum, produced efficient emission in the mid-infrared range at around 1.