The influence of Yb3+ co-doping on optical properties of Sm3+-doped sodium tellurite glasses

Abstract

A series of Sm3+-doped sodium tellurite glasses co-doped with Yb3+ 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 Sm3+ ions are observed. The broad absorption band in the range of ~870-1100 nm corresponds to the superposition of Sm3+: 6H5/2 6F11/2 and Yb3+: 2F7/2 2F5/2 transitions. The experimental and theoretical oscillator strengths of these bands were calculated by Judd-Ofelt theory. The optical band gap energy (Eopt) 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 4G5/26H5/2, 6H7/2, 6H9/2 and 6H11/2 were revealed under 406 nm excitation and intensity of all bands is found to be quenched with addition of Yb3+ ions. The role of Yb3+ co-doping in the optical properties is compared and understood.