Temperature dependence and quantum efficiency of ultrabroad NIR photoluminescence from Ni2+ centers in nanocrystalline Ba-Al titanate glass ceramics.

Ultrabroad near-infrared (NIR) photoluminescence from Ni2+-centers in nanocrystalline Ba-Al titanate glass ceramics was studied by temperature-dependent static and dynamic photoluminescence spectroscopy in the regime of 10 to 300 K. Photoluminescence covers the spectral range of about 1100 nm to >1600 nm with a typical bandwidth (FWHM) greater than 300 nm. For UV-LED excitation at 352 nm, an internal quantum efficiency of 65% is obtained. The excited state lifetime τ at room temperature is 39 μs. The stimulated emission cross section σ(em) is 8.5×10(-20) cm2, resulting in a practical figure of merit, σ(em) * τ, of 3.3×10(-24) cm2 s at room temperature. These properties suggest suitability as a broadband gain medium for tunable lasers and optical amplifiers.