Near infrared long-persistent phosphorescence in La3Ga5GeO14:Cr3+ phosphor

Near infrared (NIR; 660-1300 nm) long-persistent phosphorescence from Cr3+ ions with persistence time of more than 1 hour was realized in La3Ga5GeO14:Cr3+ phosphor (with or without co-dopants such as Li+, Zn2+, Ca2+, Mg2+ and Dy3+). The NIR phosphorescence can be effectively achieved under UV illumination (similar to 240-360 nm) but is barely achieved by blue light (similar to 480 nm) irradiation, even though the blue light excitation are effective to the NIR fluorescence. The NIR phosphorescence mechanisms were discussed by measuring the irradiation energy dependence of the phosphorescence intensity. (C) 2010 Optical Society of America