Fluorescence intensity ratio method for temperature sensing

A thermometry method based on the ratio between the valley intensity formed by fluorescence peak overlap and the peak fluorescence intensity has been developed. Excited by a 405 nm laser, the valley to peak ratio (VPR) of the emissions originating from D-5(0) to F-7(2) Stark sublevels in Eu3+-doped CaWO4 shows a monotonic change with temperature. Spectrum analysis indicates that this monotonic increase is caused by the homogeneous broadening of the spectral lines as the temperature increases. The relative sensitivity S-r is in the magnitude of 10(-4) K-1 in the experimental temperature range of 303-573 K. (C) 2015 Optical Society of America