Figure 5

Log–log dependence of the up-conversion intensities of 1.0 mol% Er3+ and 7.97 mol% Yb3+ co-doped Na5Lu9F32 single crystal at 525,548, 668 nm emissions as a function of the excitation power at 980 nm.
Log–log dependence of the up-conversion intensities of 1.0 mol% Er3+ and 7.97 mol% Yb3+ co-doped Na5Lu9F32 single crystal at 525,548, 668 nm emissions as a function of the excitation power at 980 nm.