Optical thermometry based on the red upconversion fluorescence of Er3+ in CaWO4:Yb3+/Er3+ polycrystalline powder

摘要

Based on the fluorescence intensity ratio method, the temperature-sensing behavior through thermally coupled levels (TCL) of the H-2(11/2) and S-4(3/2) states as well as the sublevels of the F-4(9/2) state of Er3+ has been studied. The thermometry is observed to be dependent on the pump power for the 2H11/2 and 4S3/2 states, leading to an error of more than 20 K at 478 K. By utilizing the sub-levels of the F-4(9/2) state, such a problem could be solved. The maximum sensitivity is about 0.15% K-1 at 298 K. This will provide guidance on selecting appropriate and practical TCL for precisely sensing the temperature. (C) 2016 Optical Society of America