Compositional dependences on the mechanism of upconversion in Nd3+/Tm3+ co-doped chalcohalide glasses

Abstract Mechanisms of the compositional dependence of blue emission from Nd 3+ /Tm 3+ co-doped Ge–Ga–S–CsBr chalcohalide glasses were investigated. The blue upconversion emissions (centered at 475 nm) due to the Tm 3+ : 1 G 4 → 3 H 6 transition decreased as the CsBr/Ga ratio in glasses while the other upconversion emissions from the Nd 3+ ions increased. Changes in the local environment of rare-earth ions incurred by the CsBr addition significantly increased the excited state absorption within Nd 3+ ions. This resulted in the decrease in the Nd 3+ → Tm 3+ energy transfer rates that led to the large decrease in blue upconversion emission.