YAG:CR3+ for wide ranging temperature sensing: correlation of theory and experiment

Results are presented on the cross-correlation of the results of an accurate theoretical model with experiment data obtained for YAG:Cr3+ used as a temperature sensor, obtained over a wide range of temperature, including the cryogenic and biomedical (approximately 37 degree(s)C) region, and a close correlation is seen. Both sets of results support the hypothesis that the phonon-induced transitions between the 2E and 4A2 states have a significant effect on the lifetime of the YAG:Cr3+ fluorescence at low temperatures, where the concept of a single equivalent phonon is proposed to account for the mixing effect of phonons with various energy, and is used to modify the single configurational coordinate model discussed. Typical temperature discrepancies between the theoretical and experimental systems are 0.4 K at 300 K, 0.8 K at 500 K and 0.4 K at 900 K.