Broadband near-infrared luminescence from transparent glass-ceramics containing Ni²⁺-doped SrTiO₃ nanocrystals

Transparent strontium titanium silicate glass-ceramics (GCs) containing Ni²⁺-doped SrTiO₃ nanocrystals were synthesized by heat treatment method. Absorption spectra confirmed that the coordination environment of Ni²⁺ ions was changed from the trigonal bipyramid fivefold sites in as-cast glasses to the octahedral sites in the GCs. Upon 980 nm laser excitation, the GCs exhibited broadband near-infrared emissions covering 1.1-1.7 μm wavelength region with the full width at half maximum (FWHM) of more than 290 nm and fluorescent lifetime of up to 735 μs, which originated from the ³T_2g (³F) → ³A_2g (³F) transition of octahedral Ni²⁺ ions in the SrTiO ₃ nanocrystals. This kind of Ni²⁺-doped transparent GCs have potential applications in super-broadband optical amplifiers and tunable lasers.