Upon 976 nm diode laser excitation, the temperature dependence of the red upconversion emission of Er3+ in CaWO4:Yb3+/Er3+ phosphor was studied from 298 to 478 K. The spectrum was verified to consist of two Stark components originating from two Stark sublevels of 4F9/2 excited state to 4I15/2 ground state of Er3+. The valley-to-peak intensity ratio (VPR) of this double-peak spectrum was found to increase linearly with the rise of temperature. The maximum relative sensitivity of this VPR method was obtained to be about 0.20% K-1 at 298 K. Moreover, a study on the power dependence was also performed, suggesting that VPR method is immune to the pump power and is thus suitable for monitoring the temperature.
All Science Journal Classification (ASJC) codes
- Atomic and Molecular Physics, and Optics