Yb3+/Tm3+ co-doped germanate-tellurite glass: conversion luminescent and temperature-sensing characteristics

Tm3+/Yb3+ co-doped germanate-tellurite glasses were prepared by high temperature melting with components of 50GeO2-20TeO2-25Na2O-3Ga2O3-2Nb2O5-2Yb2O3-xTm2O3 (x = 0.25, 0.5, 1, 1.5, 2 mol%). According to the absorption spectrum and J-O theory, the spectral line intensity parameters (Ω2, Ω4 and Ω6) of Tm3+ ions and the spectral parameters of each excitation energy level transition were calculated. Under the excitation of 980 nm LD, the up-conversion and down-conversion emission spectrum of glasses at different concentrations of Tm3+ ions were measured with the emission wavelengths at 478, 651, 808 ,1484, and 1937nm respectively, and the concentration quenching of each luminescence was found, the up-conversion emission intensity was maximum at the doping concentration of 0.1mol%, and the concentration quenching of Tm3+ ions was analyzed. Furthermore, the optical temperature sensing properties was investigated based on the 3F2 and 3H4 levels of Tm3+ ions.