The influence of Yb~(3+) Co-doping on Optical Properties of Sm~(3+) -doped Sodium Tellurite Glasses

摘要

A series of Sm~(3+)-doped sodium tellurite glasses co-doped with Yb~(3+) were synthesized by melt quenching technique. The amorphous nature of the glasses was confirmed by X-Rays diffraction technique. From UV-Vis-NIR spectroscopy, eight absorption peaks of Sm~(3+) ions are observed. The broad absorption band in the range of -870-1100 nm corresponds to the superposition of Sm~(3+): ~6H_(5/2)→~6F_(11/2) and Yb~(3+): ~2F_(7/2)→~2F_(5/2) transitions. The experimental and theoretical oscillator strengths of these bands were calculated by Judd-Ofelt theory. The optical band gap energy (E_(opt)) values for direct allowed transition and Urbach energy were found to be in the range of 2.73-2.91 eV and 0.21-0.27 eV respectively. Four luminescence emission bands ~4G_(5/2)→~6H_(5/2),~6H_(7/2),~6H_(9/2) and ~6H_(11/2) were revealed under 406 nm excitation and intensity of all bands is found to be quenched with addition of Yb~(3+) ions. The role of Yb~(3+) co-doping in the optical properties is compared and understood.