Investigation of spectral output of Er3+ and Yb3+/Er3+ doped TeO2-ZnO-BaO glasses for photonic applications

Er3+ and Yb3+/Er3+ doped TeO2-ZnO-BaO glasses were synthesized using the melt quenching technique with two different Er3+ concentrations. The refractive index was calculated to be around 2.14 from the optical band gap energies of the glasses. Under 975 nm laser excitation, weak blue, strong green and red emissions were observed in the visible region, while broadband emission around 1530 nm was recorded in the near infrared region. The increase in red emission intensity as a result of energy transfer from Yb3+ ions to Er3+ ions in Yb3+/Er3+ co-doped glasses is clearly reflected in the change in color coordinates. The temperature sensing abilities of the glasses were determined from the intensity ratios of light emitted from thermally coupled energy levels (H-2(11/2) and S-4(3/2)) of Er3+ ions. The highest absolute sensitivity was determined as 0.0046 K-1 at 453 K for Er3+ doped glass and 0.0067 K-1 at 353 K for Yb3+/Er3+ co-doped glass. These results show that Er3+ and Yb3+/Er3+ doped TeO2-ZnO-BaO glasses are promising candidates for both lighting and optical temperature sensors.