Optical properties of Mg2+, Yb3+, and Ho3+ tri-doped LiNbO3 crystals
Dai Li1, †, Liu Chun-Rui1, Tan Chao1, Yan Zhe-Hua1, Xu Yu-Heng2
       

(color online) Plots of the logarithemic up-conversion intensity versus logarithmic excitation power at 980 nm of Mg:Yb:Ho:LiNbO3 sample.