Study On Properties Of High-Q Optofluidic Microcavity

As a new frontier technology,Optofluidic microcavity sensing possess not only ultrahigh quality(Q)factors and ultralow mode volumes of traditional optical microcavity,but also low consumption and high integration of microfluidic.In science research,optofluidic microcavity sensing provides a good platform for basic research and application development in material science,chemistry,life science,biomedicine and other fields.This dissertation focuses on the whispering galley mode(WGM)microcavity and Fabry-Pérot cavity,has designed and fabricated several types of high-Q optofluidic microcavity.Using these devices,we have successfully realized low threshold lasers and high sensitivity sensors.The main achievements are as follow:1.A new structure of microbubble-embedded Fabry-Pérot(MBFP)cavity has been proposed and fabricated.Higher Q-factor,smaller mode volumes and more stable performance can be achieved in MBFP.The camber of microbubble,position inside the FP cavity,refractive index of liquid core and mirror misalignment are systematically investigated in MBFP using a finite-element method.The calculation results show that MBFP cavity has strong optical confinement in the lateral direction with a tight mode radius and high tolerance to mirror misalignment.The Q value of MBFP cavity is 1-2orders higher than that of plano-plano FP cavity.We experimentally realize MBFP optofluidic lasers with lasing threshold as low as 1.25?J/mm~2.The threshold in MBFP is one magnitude lower than the Planar-FP.In addition,the transverse mode of the output laser can be also selecting in MBFP.2.For the first time,a high-Q microbottle made from egg white has been fabricated and experimentally demonstrated.As a natural protein,egg white has desirable properties for biosensing applications,including non-toxicity,biodegradability,biocompatibility,and high transparency in the visible light band.The Q-factor of the self-assembled ovalbumin protein microbottle is on the order of 10~5.The bio-microcavity is simple in preparation,convenient in material acquisition and has good biological properties,which had some potential applications for in-vivo biosensing.In addition,stable,packaged,quasi-droplet and droplet microcavities are proposed and fabricated to overcome the defects in droplet evaporation.The lasing packaged droplet and quasi-droplet microcavity sensors with a high thermal sensitivity of up to205.3 pm/~oC are experimentally demonstrated.The fabricated thermal sensor is superior due to its ultrahigh sensitivity and robust properties,which have significant potential in environmental monitoring,biomedical applications,and photothermic devices.3.We introduce and systematically study a novel biochemical sensor based on water-immersion-objective(WIO)pumped on-chip microdisk laser.This WIO pumped configuration is an open sensing system.By monitoring the laser wavelength,any feeble disturbance of the RI of the water can be detected in real-time.Then,basic physical elements of RI and temperature sensing is tested.Finally,proof-of-concept demonstration of chemical sensor is performed by observing the process of salt dissolution in water and diffusion of two droplets with different RI.Our results suggest that the WIO pumped configuration has the advantage of easy-to-operated,responding quickly and detected in real-time,which provided a promising technology platform for chemical reaction kinetics and multifunctional biological monitoring and treatment.