Optical temperature sensing through extraordinary enhancement of green up-conversion emissions for Er–Yb–Mo:Al2O3

The extraordinary enhancement of green up-conversion emissions originated from the 2H11/2 → 4I15/2 and 4S3/2 → 4I15/2 transitions is obtained for the Er–Yb–Mo:Al2O3 with a 976 nm laser diode excitation. It indicates that such green enhancement arises from the high excited state energy transfer with |2F7/2, 3T2> state of the Yb3+–MoO42− dimer to the 4F7/2 level of Er3+. Fluorescence intensity ratio (FIR) technique based on the green up-conversion emissions of the Er–Yb–Mo:Al2O3 has been studied as a function of temperature. With an excitation power of 2 mW, the maximum of sensitivity and temperature revolution is approximately 0.0051 K−1 and 0.3 K in the range of 294–973 K, respectively. The Er–Yb–Mo:Al2O3 with intense green up-conversion emissions, a higher operating temperature and revolution indicates that it is a promising material for application in optical temperature sensing.