Analogy To Quasi-conformal Transformation Optical Devices Based On Optofluidics

Optofluidics is a fast-developing subject combining microfluidics and optics.The optical devices are directly integrated in the optofluidic system,and play an important role in bio-chemical area.As the developing of optofluidics,the characteristics of guiding light of optofluidic system attract much attention.Based on the step index formed by fluidics,many optofluidic waveguides have been demonstrated.For the gradient index formed by fluidics,it found that much classic optical phenomenon could be realized.The index profile is analogy to the quasi-conformal mapping for a diffusion-dominated process,and it could be used to design transformation optic devices,such as invisible cloak,waveguide corner.The refractive index profile in optofluidic system is formed by natural diffusion of fluids,avoiding micro/nano fabricating process in traditional solid transformation optic devices.The method using liquids is low-cost and easy-fabricated,and it is also real-time switchable.This dissertation analyses the convection-diffusion profile based on Navi-Stokes Equation,and designs transformation optic devices based on the profile.The liquid devices could realize stealth and light guiding.The main works included in this dissertation are:1.The refractive index profile by liquids in optofluidic system is analyzed based on Navier-Stokes Equation for different circumstances,including different flow rates and different shapes.It proves that the profile formed by convection-diffusion at low flow rate is analogy to the quasi-conformal profile.The rules of optofluidic chips designing are also analyzed.2.A switchable optofluidic invisible cloak has been designed based on convectiondiffusion.It experimentally shows that the cloak could operate at visible light frequencies of 400 nm,488nm,532 nm and 588 nm.The cloak-on state and cloakoff state are also shown for those wavelengths,Two incident angle of 20° and 70° are experimentally shown.The error of the cloak is analyzed and the performance under quasi-conformal mapping and convection-diffusion mapping are simulated as well.3.A switchable optofluidic waveguide bend is designed and experimentally realized.The experiments show that the bend has no loss for bending 90° and 180°.Analyzing the performance of traditional fiber and optofluidic waveguide bend under the same bending degree,and the mode changing for different bending degrees.The switch characteristics of optofluidic waveguide bend is also shown experimentally.