Efficient Holographic Polymer Dispersed Liquid Crystal Bragg Grating Preparation Study

Holographic polymer dispersed liquid crystal(HPDLC) is a kind of novel photoelectronic information materials,it has many perfect characters including high diffraction efficiency, rapid response and easy manufacture.HPDLC devices are potentially useful for optical communication,panel display,information storage,holographic display and integrated optics,especially for fabricating the optical switching because the diffraction efficiency can be modulated by the electric field.In the past two decades,people have done plenty of theoretical and experimental research on HPDLC.However,some characters,such as the diffraction efficiency and driving voltage of the HPDLC device,still need to be improved.Focusing on the subject of making good performance HPDLC volume Bragg Grating,we have done several works as below:1.The polymerization process of different functional group acrylate cured by gaussian beam have been studied.The parameters of making HPDLC under present conditions have been obtained and optimized through comparing different curing methods and changing composition percentage of the sample.2.The integrated system of making HPDLC optical switching and real-time measurement was established.The affect of different curing intensity and time on diffraction, transmittance and scattering loss during the process of making HPDLC.3.The grating structure and morphology of the HPDLC optical switching have been analyzed through polarizing microscope and Scanning Electron Microscope(SEM);the first order diffraction efficiency,the dependence of diffraction efficiency on incident angle and polarization of the probing light;as well as the driving performance of the HPDLC sample have been tested,with the measured threshold voltage of 4V/μm and the switching voltage of 15 V/μm.4.Theoretical research have been made based on Zhao's one dimensional diffusion-reaction model.We have proposed a analytical method of determining the reaction and diffusion constant in the model,thereafter the first order diffraction efficiency of the HPDLC sample measured during the curing process have been simulated,the simulation results matched perfectly with the experiment data.