Ultrahigh-resolution whispering gallery mode thermometer based silica-microsphere

This paper proposes and implements a high-resolution sensing system using an ordinary microsphere whispering gallery mode (WGM) sensor. In exceptional cases, the microsphere resonators can produce satisfactory and dense resonant dips when coupled with tapered fiber, and these resonant dips usually have extremely high-quality factors. This paper explores the advantages of Pound-Drever-Hall (PDH) laser frequency stabilization technology in characterizing the resonance dip variation of high-order WGM in microsphere cavities. PDH technology reduces the difficulty of sensor signal monitoring and improves the detection accuracy and resolution of the WGM sensor. Finally, the system monitors the ambient temperature continuously in real-time and achieves an ultra-high resolution of 2.32×10-5 °C.