Figure 4From: Use of thulium-sensitized rare earth-doped low phonon energy crystalline hosts for IR sourcesTemperature dependence of infrared fluorescence from Tm3+:YCl 3 . Normalized fluorescence intensity versus temperature between 300 and 500 K for Tm3+:YCl3. The fluorescence intensity of the 3 F4 level at 300 K is normalized to 1. The sample has a Tm3+ concentration of 0.7 × 1020 ions/cm3.Back to article page