The Research On Microsphere Quality Factor By Continuous-wave Cavity Ring-down Technique

With the development of society, the industrial production process will emit largeamounts of toxic and hazardous substances, which would seriously endanger human health.It’s a huge challenge to monitor these substances fast and availably for high-sensitivity sensortechnology.In recent years, the rapid development of optical microsphere provide new ideas forhigh-sensitivity sensor technology, which is widely concerned because it has a very smallmode volume and high quality factor, and is increasingly used as the core of sensitivecomponents of the new sensors, and obtain better detection results. The sensitivity andaccuracy of these new sensors are affected directly by microsphere’s quality factor, therefore,measuring its quality factor accurately can not only provide feedback data for the processingof sensitive components, but also accurate numerical analysis for high-sensitivity sensors.In this paper, we propose a microsphere quality factor measurement system based oncontinuous-wave cavity ring-down technique. Through the analysis of the microsphere basictheory and continuous-wave cavity ring-down technique basic principles, we complete thedesign of the experimental program; through the depth analysis of the method of extractingthe ring-down time, we establish that we utilize the Levenberg-Marquardt algorithm to fit thering-down signal, and extract the ring-down time; In the choice of the experimental apparatus,we analyze the operating principle and performance parameters of the key components, whichlays a solid foundation for the measurement system; In order to verify the feasibility of theexperimental program, we set up a complete cavity ring-down analysis and test system, andobtain the ring-down time of a typical microsphere by experiment, and calculate its qualityfactor.