Optical temperature sensing of the non-thermally coupled energy levels (N-TCLs) based on fluorescence intensity ratio (FIR) technologies has excellent temperature sensitivity and signal recognition properties. In this study, a novel strategy is established to enhance the low-temperature sensing properties by controlling photochromic reaction process in Na0.5Bi2.5Ta2O9: Er/Yb samples. The maximum relative sensitivity reaches up to 5.99% K-1 at cryogenic temperature of 153 K. After irradiation with commercial laser of 405 nm for 30 s, the...