Compact and sensitive Er3+/Yb3+ co-doped YAG single crystal optical fiber thermometry based on up-conversion luminescence

Compact and sensitive Er3+/Yb3+ co-doped YAG single crystal optical fiber thermometry based on up-conversion (UC) luminescence is presented. The thermal probe is a YAG single crystal fiber with end Er3+/Yb3+ co-doped grown by laser heated pedestal growth method. Excited by a 976 nm laser diode, the UC fluorescence intensity ratio (FIR) of the Er3+ ions in two emission bands (2H11/2,4S3/2 → 4I15/2) was investigated in the temperature range from 298 K to 723 K. The results indicate that the maximum temperature sensitivity is approximately 0.00486 K−1 at 577 K. Thus, the Er3+/Yb3+ co-doped YAG single crystal fiber has potential application in optical thermometry by the FIR technique. Furthermore, the thermal probe has compact structure and high thermal stability, making it a more convenient and effective optical fiber temperature sensor.