| The optical sensor based on whispering gallery mode has the advantages of high sensing sensitivity and the small size.It has broad application prospects in many fields,such as the ocean,biology,etc.In this paper,the whispering gallery mode sensor based on the hollow microsphere cavity is studied.Apart from being a sensor,the hollow core can also work as a channel for the delivery of the microfluidic.Flexible sensor can be designed by injecting with microfluidic for multiple parameters sensing.Temperature and magnetic field optical fiber sensors were studied by injecting microfluidic with high thermo-optical coefficient and magnetic fluid,respectively.The main work of this paper includes:1.The whispering gallery mode microcavity is introduced.The current status of the researches about the temperature and magnetic field sensing of the whispering gallery mode microcavity fiber sensor and the fabrication of hollow microsphere cavity are summarized.Based on the analytical calculation,the distribution characteristics of the electric field is revealed.The coupling theory between the tapered fiber and the hollow microsphere cavity is introduced.2.Based on hydrogen oxygen flame melting stretching system,the fabrication of the hollow microsphere cavity and tapered fiber is proposed.Using the two-step heating process method,we get a series of hollow microsphere cavities with outer diameters ranging from 300?m to 500?m,thicknesses ranging from 1?m to 5?m.And tapered fibers with 2?m to 3?m waist diameter are fabricated.The main parameters of the hollow microsphere cavity are measured.3.The sensing model of temperature of the hollow microsphere cavity fiber sensor is deduced.Ocean temperature sensing based on this sensor is investigated.The effect of sensor parameters on temperature sensitivity is investigated with the experiments using different parameters hollow microspheres,tapered fibers with different waist diameters and different kinds of solution.The dynamic response characteristics is experimentally analyzed.A high sensitivity of 396.70pm/?is obtained when the hollow microsphere is filled with ethanol.A high temperature resolution 1.75×10-3?is obtained when the hollow microsphere is filled with cyclohexane.4.The sensing model of magnetic field of the hollow microsphere cavity fiber sensor is studied.Magnetic field sensing based on this sensor using two different mechanisms is investigated.Compared with the body sensing mechanism of magnetic refractive index change,magnetic field sensing sensitivity is increased by 3.6 times based on the magnetic fluid's magnetic nanoparticles adsorption and shedding surface sensing mechanism.On the basis of this,the effect of hollow microsphere cavities'parameters on magnetic field sensitivity is investigated. |
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