Color variety of up-conversion emission of Er3+/Yb3+ co-doped phosphate glass ceramics

The sample of Er3+/Yb3+ co-doped phosphate glass ceramic was prepared. At 975 nm laser diode (LD) excitation, the strong up-conversion (UC) emissions were observed, which were the UC green emission at 510–570 nm and the UC red emission at 636–692 nm, respectively. At low pump power (126 mW), the red emission is primary, and the color purity Rcp is 0.81. With the increasing of pump power, the emission color gradually varies from red to green. The intensity of the green emission is stronger compared to that of the red emission at high power (868 mW), and the color purity Rcp is 0.76. Thus, this material can be applied to fluorescence anti-counterfeiting by the color variety of UC emission under different pump power.