Laser action and upconversion of Nd3+ in tellurite bulk glass

Laser action together with upconversion processes that produce green, orange, and red emissions in Nd3+-doped tellurite glass (TeO2–TiO2–Nb2O5) have been investigated. The upconversion processes were conducted in such a way that the dynamics of the visible fluorescence was analyzed under lasing and nonlasing conditions. The features observed in the time resolved upconverted emission show the existence of excited state absorption of both pump radiation and laser emission.