Effect of cross relaxation on the 1470 and 1800 nm emissions inTm3+:TeO2–CdCl2 glass

Abstract

We have used spectroscopic methods to investigate the effect of cross relaxation on the 1470 and 1800 nmemissions in Tm3+:TeO2–CdCl2 glass for Tm3+ ion concentrations of 0.05, 0.1, 0.25, 0.5 and 1.0 mol%. The emission spectra obtained under800 nm excitation reveal the existence of energy transfer via cross relaxation among theTm3+ ions. As a result, as the thulium concentration is increased, the strength of the 1470 nm emission isfound to decrease in relation to that of the 1800 nm emission. The analysis of the time evolution ofthe 3F4 emission due to the transition further shows that the electronic mechanism responsible for the ion–ioninteraction can be identified as an electric dipole–dipole energy transfer process and occursin the diffusion-limited relaxation regime. The average critical distance parameter whichprovides a measure for the strength of cross relaxation was further determined to be 17.9 Å.