Structural and luminescence studies on Er3+/Yb3+ co-doped boro-tellurite glasses

The present work reports structural and optical behaviour of the Er3+/Yb3+ co-doped boro-tellurite glasses 50TeO2 + 15H3BO3 + (5 − x − y)La2O3 + 15MgCO3 + 15SrCO3 + xEr2O3 + yYb2O3 (where x = 1, y = 0, 0.5, 1 and 2 in wt%) studied through Fourier transform infrared (FTIR), Raman, absorption, luminescence, upconversion luminescence and lifetime measurements for green laser applications. The TeOTe, O3BOBO3 bond bending vibrations and the fundamental stretching vibration of OH groups are confirmed through FTIR and Raman spectra. Through the absorption spectra, bonding parameters, oscillator strengths and Judd–Ofelt (JO) parameters were calculated and reported. From the luminescence spectra, radiative parameters have been calculated for the 2H9/2→4I15/2,4S3/2→4I15/2 and 4I13/2→4I15/24I13/2→4I15/2 excited state transitions. Upconversion luminescence spectra of the prepared glasses have been recorded and the excited state absorption (ESA) and Energy transfer (ET) processes are discussed. The luminescence decay curves for the 4I13/2→4I15/24I13/2→4I15/2 transition of the title glasses under 980 excitation wavelength have also been studied and reported.

Energy level diagram of Er3+ and Yb3+ ions and upconversion mechanisms of Er3+/Yb3+ doped boro-tellurite glasses under 980 nm excitation.Figure optionsDownload as PowerPoint slideHighlights
► The intensity of the 4I11/2(Er3+) transition increases linearly with Yb3+ content.
► Higher oscillator strengths for the 2H11/2 and 4G11/2 confirm the lower asymmetry.
► Enhancement in upconversion emission is observed through energy transfer from Yb3+ to Er3+ ion.
► E2YBT glass is suggested for suitable green laser applications.