Thermal Lens (TL) and spectroscopic characterizations were performed in 70TeO2-19WO3-7Na2O-4Nb2O 5 (mol%) tellurite glasses. TL measurements were accomplished in Er3+/Tm3+ co-doped tellurite glasses in function of the Tm2O3 concentration (0.4 -1.6 ×1020 ions/cm3). Fluorescence spectra at 488 nm showed that Er 3+/Tm3+co-doped tellurite glasses present several emission bands between (500-1800) nm. However, the more iniense emission bands correspond to the Er3+ and Tm3+ transitions ( 4I13/2 → 4I15/2 and 3F4 → 3H6), respectively. The absolute nonradiative quantum efficiency (φ) was determined by TL method. Higher values of φ were obtained with the increase of Tm2O 3 concentration inside of the Er3+/Tm3+ co-doped tellurite glasses. These results are corroborated by the Judd-Ofelt calculations.6116Ryba-Romanowski, W., Effect of Temperature and activator concentration on luminescence decay of erbium-doped tellurite glass (1990) J. Lumin., 46, pp. 163-172Tanabe, S., Hirao, K., Soga, N., Upconversion fluorescences of TeO2 and Ga2O 3. based oxide glasses containing Er3+ (1990) J. Non-cryst. Solids, 122, pp. 79-82Inoue, S., Nukui, A., Yamamoto, K., Yano, T., Shibata, S., Yamane, M., Refractive index patterning of tellurite glass surfaces by ultra short pulse laser spot heating (2002) J. Mater. Sci., 37, pp. 3459-3465Huang, L., Jha, A., Shen, S., Chung, W.J., Visible emissions at 592 and 613 nm in Er3+-Eu3+ -codoped tellurite fibers (2004) Opt. Commun., 239, pp. 403-408Chillece, E.F., Rodriguez, E., Neves, A.A.R., Moreira, W.C., César, C.L., Barbosa, L.C., Er3+-Tm3+ co-doped tellurite fibers for broadband optical fiber amplifier around 1550 nm band (2005) Opt. Fiber Tech.Tanabe, S., Suzuki, K., Soga, N., Hanada, T., Mechanisms and concentration dependence of Tm3+ blue and Er3+ green up-con version in codoped glasses by red-laser pumping (1995) J. Lumin., 65, pp. 247-255Dai, S.X., Yang, J.H., Liu, Z.P., Wen, L., Hu, L.L., Jiang, Z.H., The luminescence of Er3+, Yb3+, Tm 3+-codoped tellurite glass pumped at 970 nm (2003) Acta Physica Sinica, 52, pp. 729-735Shen, S.X., Jha, A., Huang, L.H., Joshi, P., 980-nm diode-pumped Tm3+/Yb3+-codoped tellurite fiber for S-band amplification (2005) Optics Letters, 30, pp. 1437-1439Shen, X., Nie, Q., Xu, T., Peng, T., Gao, Y., Green and red upconversion emission and energy-transfer between Er 3+ and Tm3+ions in tellurite glasses (2004) Phys. Lett. A, 332, pp. 101-106Daf, S., Yang, J., Xu, S., Dai, N., Hu, L., Jiang, Z., The spectroscopic properties of Er3+, Yb3+, Tm 3+ -codoped tellurite glass (2003) Proc. SPIE, 4990, pp. 150-156. , Rare-Earth-Doped Materials and Devices Vil, S. Jiang, J. Lucas (Eds.)Lima, S.M., Sampaio, J.A., Catuncla, T., Bento, A.C., Miranda, L.C.M., Baesso, M.L., Mode-mismatched thermal lens spcctrometry for thermo-optical properties measurement in optical glasses: A review (2000) J. Non-cryst. Solids, 273, pp. 215-227Sampaio, J.A., Catunda, T., Gama, S., Baesso, M.L., Thermo-optical properties of OH-free erbium-doped low silica calcium aluminosilicate glasses measured by thermal lens technique (2001) J. Non-cryst. Solids, 284, pp. 210-216Lima, S.M., De Camargo, A.S.S., Nunes, L.A.O., Catunda, T., Fluorescence quantum efficiency measurements of excitation and nonradiative deexcitation processes of rare earth 4f-states in chalcogenide glasses (2002) Appl. Phys. Lett., 81, pp. 589-591Oliveira, S.L., Lima, S.M., Catunda, T., Nunes, L.A.O., Rohling, J.H., Bento, A.C., Baesso, M.L., High fluorescence quantum efficiency of 1.8 μm emission in Tm-dopcd low silica calcium aluminate glass determined by thermal lens spectroscopy (2004) Appl. Phys. Lett., 84, pp. 359-361Jacinto, C., Oliveira, S.L., Nunes, L.A.O., Catunda, T., Bell, M.J.V., Thermal lens study of the OH influence on the fluorescence efficiency of Yb3+ -doped phosphate glasses (2005) Appl. Phys. Lett., 86Sampaio, J.A., Gama, S., Baesso, M.L., Catunda, T., Fluorescence quantum efficiency of Er3+ in low silica calcium aluminate glasses determined by mode-mismatched thermal lens spectromctry (2005) J. Non-cryst. Solids, 351, pp. 1594-1602Pilla, V., Lima, S.M., Catunda, T., Medina, A., Baesso, M.L., Jenssen, H.P., Cassanho, A., Thermal quenching of the fluorescence quantum efficiency in colquiriite crystals measured by thermal lens spcctrometry (2004) J. Opt. Soc. Am. B., 21, pp. 1784-1791Pilla, V., Catunda, T., Balogh, D.T., Faria, R.M., Zilio, S.C., Thermal lensing in Polyvinyl alcoholVpolyaniline blends (2002) J. Polym. Sc., Part B Polym. Physics, 40, pp. 1949-1956Lima, S.M., Catunda, T., Lebullenger, R., Hernandes, A.C., Baesso, M.L., Bento, A.C., Miranda, L.C.M., Temperature dependence of thermo-optical properties of fluoride glasses determined by thermal lens spectrometry (1999) Phys. Rev. B, 60, pp. 15173-15178Lima, S.M., Sampaio, J.A., Catunda, T., De Camargo, A.S.S., Nunes, L.A.O., Baesso, M.L., Hewak, D.W., Spectroscopy, thermal and optical properties of Nd3+ -doped chalcogenide glasses (2001) J. Non-cryst. Solids, 284, pp. 274-281Zou, X., Izumitani, T., Spectroscopic properties and mechanisms of excited state absorption and energy transfer upconversion for Er3+ -doped glasses (1993) J. Non-cryst. Solids, 162, pp. 68-8
