Fabrication And Characterization Of Polymer Based Optical Resonate Microcavity Via Microfluidics

Optical micro-cavity is an outstanding potential sensor for biomedical detection and monitoring due to its high quality factor,high detective capability,small mode volume and universal detection mode(physical absorption).There are several types of optical micro-cavities such as Fabry-Perot,photonic crystal and whispering gallery modes in recent years.Whispering gallery mode particle(WGMP)has attracted huge attention in the field of biological detection.In the merits of its high sensitivity,versatility,wide applicability and no need for labels,it is getting rapidly increasing attention in the field of biomedical detection.Despite all previous and achievements in biomedical detection,there are quite few options about WGMP fabrication.Most of previous progress are achieved on the basement of micro-toroid structure which requires very complicated fabrication procedure and the cost is not affordable for general application yet.People try to simplify the structure from micro-toroid to micro spheres,micro cylinders and even micro-disks to simplify fabrication procedure and reduce the cost.Those simplified micro-cavities did ease the fabrication process in certain aspect but also bring performance descending and less light resonation modes problem.We present a selfcoupling low-cost bulk WGMP preparation method by microfluidic.In this paper,fluorescent dyes are loaded into the resonant microcavity to achieve self-coupling,which removes the complex and fragile coupling part of the WGM resonator,frees WGMP from the coupled fiber,and avoids the possibility of adjusting the position and angle.Test system errors.The self-coupling optical microcavity can precisely adjust the amount of fluorescent dye loaded as needed,and can systematically adjust the optical properties such as laser threshold,etc.,and provide a reliable preparation platform for systematic research on the performance of optical microcavities.In this dissertation,the driving pressure,ratio and pressure difference of the dispersed phase and continuous phase in the microfluidic preparation of WGMP and the posttreatment conditions of microsphere solidification were investigated.Finally,micronsized monodisperse polystyrene microspheres were successfully prepared.Self-coupling optical microcavity with Nile red were successfully prepared by incorporating fluorescent dye Nile red into polystyrene microspheres.Its particle size distribution and fluorescence spectra were characterized and its optical resonance properties was tested.After detailed optical characterization,its quality factor and laser threshold were calculated,which proved that this simple method can prepare monodisperse polystyrene optical microcavity in large quantities.Further research will expand the preparation of microspheres for a wide variety of functionalization.This preparation platform provides a new method of the preparation of WGM optical microcavities,allowing more people to systematically research and develop the application of WGM optical microcavities,and to lay a good foundation for the mass production and commercial application of WGM optical microcavities,and to narrow the gap between academic research and practical applications.