Concentration-dependent energy-transfer processes in Er^3+- and Tm^3+-doped heavy-metal fluoride glass

The energy-transfer rate from the Er(3+)(4)I(13/2) level to the Tm(3+)(3)H(4) level (C(11')N(T)) in BaF(2)/ThF(4) fluoride glass is measured and calculated. The results can be used to determine whether rate equations can be used to predict energy-transfer rates.