Opt Lett. 2022 Dec 1;47(23):6249-6252. doi: 10.1364/OL.478285.
Ratiometric optical thermometry based on upconversion (UC) luminescence with different multi-photon processes in CaWO:Tm,Yb phosphor was developed. A new fluorescence intensity ratio (FIR) thermometry, utilizing the ratio of the cube of F emission to the square of G emission of Tm and retaining the feature of anti-interference of excitation light source fluctuations, is proposed. Under the hypotheses of the UC terms being neglected in the rate equations and the ratio of the cube of H emission to the square of G emission of Tm being a constant in a relatively narrow temperature range, the new FIR thermometry is valid. The correctness of all hypotheses was confirmed by testing and analyzing the power-dependent emission spectra at different temperatures and the temperature-dependent emission spectra of CaWO:Tm,Yb phosphor. The results prove that the new ratiometric thermometry based on UC luminescence with different multi-photon processes is feasible through optical signal processing, and maximum relative sensitivity of the thermometry is 6.61% K at 303 K. This study provides guidance in selecting UC luminescence with different multi-photon processes to construct ratiometric optical thermometers with anti-interference of excitation light source fluctuation.
基于上转换（UC）发光的比率光学测温法，在 CaWO:Tm,Yb 荧光粉中采用了不同的多光子过程。提出了一种新的荧光强度比（FIR）测温法，利用 Tm 的 F 发射的立方与 G 发射的平方之比，并保留了对激发光源波动干扰的抗干扰特性。在假设 UC 项在速率方程中被忽略，并且在相对较窄的温度范围内 Tm 的 H 发射的立方与 G 发射的平方之比为常数的情况下，新的 FIR 测温法是有效的。通过测试和分析不同温度下的功率依赖发射光谱以及 CaWO:Tm,Yb 荧光粉的温度依赖发射光谱，验证了所有假设的正确性。结果证明，通过光学信号处理，基于不同多光子过程的 UC 发光的新型比率测温法是可行的，在 303 K 时，该测温法的最大相对灵敏度为 6.61% K。本研究为选择 UC 发光不同多光子过程来构建抗干扰激发光源波动的比率光学温度计提供了指导。
