Two novel Yb:YAG-based garnet solid solutions with broader spectral bandwidth

Two novel solid solutions of Yb:YAG and Ca3Al2(SiO4)3, Yb:YAG and Mg3Al2(SiO4)3 in various molar ratios were synthesized by solid-state reactions, respectively. The spectral bandwidth remarkably increased with increasing M3Al2(SiO4)3 (M=Ca and Mg) contents, and the maximal full width at half maximum (FWHM) of absorption and emission spectra for the solid solutions are almost 9 and 3 times larger than that of Yb:YAG, respectively. This large broadening of spectral bandwidth can be attributed to the inhomogeneity in the local environment of Yb3+ caused by the cationic substitutions of Ca2+ (Mg2+) for Y3+, Si4+ for Al3+ and the high crystal-field strengths caused by distorted host sites. Meanwhile, the fluorescence lifetimes of solid solutions decrease with the increases of M3Al2(SiO4)3 contents.