Investigation On The Dynamic Reconfigurable Liquid Crystal Optical Devices Based On Optofluidics

Optofluidics is a new technology combining microfluidic and optics.By manipulating the light or fluid at micro/nano scale,the optical performance of the system can be adjusted.Traditional solid-state optical devices have many problems,such as high cost,large volume,poor tunability,etc.,which still have many limitations in practical application.Compared with the traditional solid-state optical devices,optofluidic devices are smaller in size and lower in cost.In particular,because of the selectivity of liquid composition,the optofluidic devices can realize dynamic controlling of optical properties,which meets the need of modern optical system for tunability.Liquid crystal is a soft material with anisotropy and liquid fluidity.Its unique optical and physical properties have become an important material for people to explore diversified response and tunable devices.In this paper,two kinds of dynamic reconfigurable liquid crystal optofluidic devices with advantages of both optofluidics and liquid crystal are designed and fabricated:cholesteric liquid crystal reflective optical devices based on optofluidics and nematic liquid crystal optical devices based on optofluidics and the optical properties of liquid crystal optofluidic devices are studied respectively.1、By mixing cholesteric liquid crystal with reactive liquid crystal monomer and photoinitiator,the cholesteric liquid crystal polymer template was prepared by photopolymerization and organic solvent leaching.The cholesteric liquid crystal reflective optofluidic chip was prepared by integrating cholesteric liquid crystal polymer template into the PDMS microchannel prepared by soft lithography.By taking advantage of the Bragg reflection of cholesteric liquid crystal with unique helical structure and the "Wash out-refill" cholesteric liquid crystal polymer film,a wideband adjustable cholesteric liquid crystal reflective optofluidic device is realized by regulating the "refill" of the fluid into the liquid crystal polymer network.Then we explore the influence of the flow rate and the width of the microchannel on the movement of the reflector band.2、By introducing the nematic liquid crystal polymer system,the distributed Bragg reflection film with alternating period structure and the nematic liquid crystal polarization grating were prepared by the interference exposure method.Then,two liquid crystal polymer films were combined with the optofluidics respectively to realize the dynamically adjustable nematic liquid crystal reflective optofluidic chip and the nematic liquid crystal polarized grating optofluidic chip by manipulating the fluid.The influence of fluid composition and flow velocity on the reflection and diffraction characteristics of both are also investigated.