An Er3+/Yb3+ Co-Doped Tellurite Temperature Sensor Based on Fluorescence Intensity Ratio Technology for Real-Time Thermal Monitoring of Automotive 3-D LiDAR

In this article, Er $^{{3}+}$ /Yb $^{{3}+}$ co- doped TeO2-Li $_{{2}}\text{O}$ -ZnF2-WO3-Nb2O5 (TZWLN) glasses were prepared using the melt annealing methods, and the rare Earth (RE) ion concentrations were optimized to achieve the strongest green up-conversion (UC) luminescence. Based on it, a temperature sensor drawing on the fluorescence intensity ratio (FIR) technique was developed via a dual solidification process for real-time temperature monitoring of automotive 3-D LiDAR (A3DL). The sensing performance of the sensor was evaluated in the temperature range of 252 to 453 K. The maximum absolute sensitivity ( ${S}_{a}{)}$ was $3.98\times 10^{-{3}}\,\,\text{K}^{-{1}}$ at 453 K, and the maximum relative sensitivity ( ${S}_{r}{)}$ was 0.0146 $\text{K}^{-{1}}$ at 252 K. Global rapid thermal cycling repetition experiments and local temperature jump stability experiments were conducted, and temperature information was demodulated using the FIR mathematical model. In the repetition experiments, the maximum residual sum of squares (RSSs) was $9.98\times 10^{-{3}}$ , and in the temperature jump experiments, the standard deviation of demodulated temperatures was 0.064 and 0.063. It is worth noting that the maximum measurement error of the sensor in the real-time temperature detection of the onboard LiDAR was only 0.77 K. To the best of our knowledge, this was the first report on using fluorescent temperature sensors for real-time temperature detection of A3DL. The proposed sensor has the advantages of excellent stability and repeatability, resistance to electromagnetic interference and corrosion, as well as the capacity to avoid cross-sensitivity. It offers an effective and reliable measurement scheme for real-time temperature detection in A3DL.