The effects of lanthanum addition on optical characteristics of Ge-Ga-S-AgI chalcogenide glasses

Tm3+-doped Ge-Ga-S-AgI chalcogenide glasses with the addition of La2S3 have been fabricated. The effects of La2S3 on the glass structure and the Tm3+-doped infrared emission property have been discussed. The results show that incorporation of La in the Ge-Ga-S-AgI glass matrix induces the dissociation of Ge-Ge metal bonds and transforms the [S3Ge-GeS3] bonds to GeS4 tetrahedra. A new peak at about 230 cm(-1) is detected in Raman spectra and a redshift at the visible absorbing cut-off edge is observed with introduction of La2S3. The La2S3-modified glasses exhibit enhanced emission intensity in both 1.46 mu m and 1.8 mu m emission bands and have larger solubility of rare-earth because of substitution mechanism of Tm3+ for La3+ ions. The introduction of high Tm concentration into glasses induces the attenuation of emission intensity. This phenomenon is correlated with the recurrence emission quenching effect. (C) 2017 Elsevier B.V. All rights reserved.