Greatly enhanced broadband near-infrared emission due to energy transfer from Cr³⁺ to Ni²⁺ in transparent magnesium aluminosilicate glass ceramics

Cr³⁺/Ni²⁺ co-doped optically transparent magnesium aluminosilicate glass-ceramics containing MgAl₂O₄ nanocrystals have been prepared by heat-treatment. Greatly enhanced broadband near-infrared emission centered at 1216 nm in Cr³⁺/Ni²⁺ co-doped glass ceramics is observed when compared with the Ni²⁺ single-doped glass ceramics under 532 nm excitation. The observed enhancement of infrared emission is attributed to the energy transfer from Cr³⁺ to Ni²⁺ ions in the nanocrystalline phase, which leads to the emission due to ³T₂ (³F) →+ ³A₂ (³F) transition of octahedral Ni²⁺ ions.