Figure 5
From: Use of thulium-sensitized rare earth-doped low phonon energy crystalline hosts for IR sources
Temperature dependence of infrared fluorescence from Tm3+:YCl 3 . Overlay of temperature-dependent rate model for the relative population of the three lower levels for Tm3+:YCl3 with the temperature-dependent intensity data from Figure 4. The solid lines are the model, and the markers are the data. The population of the 3F4 level at 300 K is normalized to 1. The sample has a Tm3+ concentration of 0.7 × 1020 ions/cm3.