1.5 µm Amplification and Upconversion Emission of Er3+ Doped Tellurite Glasses for Laser Applications

Abstract

In the present investigations, a series of Er3+ doped glasses with the composition 30TeO2 + (30–x) Bi2O3 + 20ZnO + 20CdO + xEr2O3 (x = 0.05, 0.1, 0.5, 1 and 3 wt%) were prepared by melt-quenching technique and characterized through FTIR, Raman, optical absorption, emission and decay curve measurements. Optical absorption spectra have been analyzed using Judd–Ofelt theory to interpret the local environment of the Er3+ ion site. In order to elucidate the potential application of Er3+ ions in the prepared glasses the radiative properties were calculated for the 4S3/2 →4I15/2 and 4I13/2→4I15/2 emission transitions. The absorption and emission cross-section for the 4I13/2→4I15/2 transition at 1.5 µm were calculated using McCumbar theory and compared with the results obtained from JO theory. The decay curves of the 4I13/2 level have been measured and the fall in lifetime value with the increase in Er3+ ion concentration can be attributed to the cross-relaxation between Er3+ ion to the free OH− radical. The upconversion emission spectra were recorded at 980 nm excitation and their energy transfer mechanism through ground state absorption and various excited state absorption are discussed.