Unprecedented multiphonon vibronic transitions of erbium ions on copper nanoparticles-containing tellurite glasses

The erbium–doped tellurite glass containing copper nanoparticles showed multi-band emission of one particular transition (4I9/2 →4I15/2, at 980 nm) due to electron-lattice coupling. The present study reports on for the first time vibronic transitions of intraconfigurational 4fn transitions of Er3+ ions in tellurite host matrix at room temperature. The mechanisms of multiphoton transitions and the effect of laser heating are discussed. This unprecedented behavior enables designing of a plethora of different applications spanning from tunable emission in the near infrared, such as laser for bioimaging and biomedical fields, to energy conversion by thermophotovoltaic conversion of thermal radiation