Optical detection of near infrared femtosecond laser-heating of Er3+-doped ZnO-Nb2O5-TeO2 glass by green up-conversion fluorescence of Er3+ ions

► Er3+ up-conversion fluorescence in an optical nonlinear ZnO-Nb2O5-TeO2 glass. ► Sensitive tool to determine the spot temperature due to femtosecond (fs) laser-heating. ► Two photon absorption estimated by Z-scan technique. ► Discussion on fs laser heating properties between SiO2-based and TeO2-based glasses. ► Optical temperature-sensing techniques providing a useful tool on development of laser processes.