The Optical Properties Of The Whispering Gallery Modes In Liquid Microspheres

The whispering gallery modes(WGMs)in micro resonate cavity possess some special optical properties,and has very important application value.The WGMs in solid micro cavity have been studied extensively,while the characteristics and applications of the WGMs in liquid micro cavity are relatively few.Based on the existing WGMs in the micro cavity,the optical properties of the WGMs in liquid microspheres and their applications are studied in this paper.the important parameters related to WGMs in the micro cavity are simulated and numerically calculated,and the basic laws are obtained.In order to achieve the research goal,a single droplet preparation method based on hollow tapered optical fiber is proposed.The method can prepare a single liquid microsphere with volume of pL level or sub pL level.The process of producing microspheres by ultrasonic atomization is described,and the advantages and disadvantages of different methods are compared.According to the different requirements of the application,the dual-fiber optical tweezers control method and the annular core single-fiber optical tweezers control method are used to control the micro-droplet in the liquid microsphere.And finally we provide a new way to study the WGMs in liquid micro droplet.The excitation method of the WGMs in the traditional solid microspheres was studied by means of fiber optic taper coupling,and then the WGMs in liquid micro droplets was excited by combining the optical fiber tweezers and the tapered fiber coupling.The resonant spectrum of the WGMs in the liquid micro sphere obtained confirms the basic law of the WGMs in the micro cavity We choose dibutyl ester as the droplet material,and DCM as doping fluorescent dye.We use the optical fiber tweezers to trap and stimulate the WGMs in the micro droplet.We observe dye lasing in the DCM doped micro droplets and complete the laser temperature sensing experiment.In the dye droplet laser experiment,the fluorescence spectra and multi-longitudinal-mode laser spectra of dye droplets were obtained.Using the dye droplets with diameter less than 20?m and dye concentration about 2.6mmol/L,the threshold value of output laser was 0.7?J.Dye droplet lasers were used to study the influence of droplet diameters on the position of laser spectra.In the experiment of dye droplet laser temperature sensing,the temperature sensing data of dye droplet laser spectra were obtained.The temperature sensitivity of the droplet laser is 0.377nm/?,which is higher than that of the WGMs in the solid material cavity,and has a higher temperature sensitivity.In addition,the problem of photobleaching of the dye is also discussed.In conclusion,the optical properties and application of the WGMs in liquid microspheres are explored in this paper,which may promote the improvement and development of the application of WGMs.