Optical temperature sensing of NaYbF4: Tm3+ @ SiO2 core-shell micro-particles induced by infrared excitation

NaYbF4:Tm3+@SiO2 core-shell micro-particles were synthesized by a hydrothermal method and subsequent ultrasonic coating process. Optical temperature sensing has been observed in NaYbF4:Tm3+@SiO2 core-shell micro-particles with a 980 nm infrared laser as excitation source. The fluorescence intensity ratios, optical temperature sensitivity, and temperature dependent population re-distribution ability from the thermally coupled D-1(2)/(1)G(4) and F-3(2)/H-3(4) levels of the Tm3+ ion have been analyzed as a function of temperature in the range of 100 similar to 700 K in order to check its availability as a optical temperature sensor. A better behavior as a low-temperature sensor has been obtained with a minimum sensitivity of 5.4 x 10(-4) K-1 at 430 K. It exhibits temperature induced population re-distribution from D-1(2)/(1)G(4) thermally coupled levels at higher temperature range. (C) 2013 Optical Society of America