Optical thermometry through infrared excited green upconversion emissions in Er3+–Yb3+ codoped Al2O3

Fluorescence intensity ratio (FIR) variation of green upconversion emissions at 523 and 545nm in the Er3+–Yb3+ codoped Al2O3 has been studied as a function of temperature using a 978nm semiconductor laser diode as an excitation source. In the temperature range of 295–973K, the maximum sensitivity and the temperature revolution derived from the FIR technique are approximately 0.0051K−1 and 0.3K, respectively. The Er3+–Yb3+ codoped Al2O3 material with the highest operating temperature up to 973K, the higher temperature revolution, and the fluorescence efficiency indicated that it is promising for applications in optical high temperature sensor.