White-light manipulation in Ho3+/Yb3+/Tm3+-doped LiNbO3 single crystals through transition metal Mn2+ ion doping

A strategy for ideal upconversion white-light emission in LiNbO3:Ho3+/Yb3+/Tm3+ single crystals is demonstrated simply through transition metal Mn2+ doping. The addition of different Mn2+ concentrations favors the probability of upconversion red emission transition, and the ratio of red-to-green is enhanced resulting in a purer upconversion white-light emission. It is observed the cross-relaxation of energy between Ho3+, Tm3+ and Mn2+ ions plays an important role in improving the red emission. The obtained results greatly benefit in the further discovery to design upconversion process and fabricate other ideal upconversion white-light materials.