Broadband infrared luminescence of Ni2+-doped silicate glass–ceramics containing lithium aluminate spinel nanocrystals

Transparent Ni2+-doped SiO2-Al2O3-Ga2O3-Li2O (LGAS) glass–ceramics embedding lithium aluminate spinel nanocrystals was prepared. After heat treatment, LiAl5O8 crystallite was precipitated in the glasses, and its size was about 3 nm. It was confirmed from the absorption spectra that the ligand environment of Ni2+ ions changed from the trigonal bi-pyramid fivefold sites in the as-made glass to the octahedral sites in the glass–ceramics. Upon excitation at 980 nm, broadband infrared luminescence centered at around 1250 nm with full width at half maximum (FWHM) more than 250 nm was observed originating from the 3T2(3F) → 3A2(3F) transition of Ni2+ in octahedral sites. The broadband near-infrared (NIR) emission from Ni2+-doped glass–ceramics can be as host materials for broadband optical amplifier.