Preparation and performance of Cr3+/Tm3+/Ho3+ co-doped fluorophosphate glasses

Fluorophosphate glasses with various Al(PO3)3 contents were prepared, and their structure, thermal properties and spectral properties were studied. The emission properties at around 2.0 μm of Cr3+/Tm3+/Ho3+ co-doped fluorophosphate glasses with different mole fractions of Tm3+ and Ho3+ were studied. The spectral strength parameters Ωt (t = 2, 4, 6) of those glasses have been calculated. Meanwhile, the spectral parameters, including the oscillator strength, spontaneous emission probability and branching ratios of Ho3+, have been calculated. The results show that the 2.0 μm emission intensity gradually grows higher with the increase of the mole fraction of Tm3+. The Tm3+→(3F4)→Ho3+ (5I7) energy transfer in (Tm3+/Ho3+) co-doped fluorophosphate glasses is very efficient, and it is dependent on the doping concentration.