适用于高空间频率透射式全息聚合物分散液晶光栅的材料研究

提出了适用于空间频率为3000 lp/mm的透射式全息聚合物分散液晶(HF-THPDLC)光栅的材料体系,并在反应动力学方面进行了深入的分析.为了能够得到高衍射效率并具有良好表面形貌的HF-THPDLC 光栅,首先确定了体系的平均官能度,使得预聚单体和液晶的扩散时间、液晶的成核时间以及于聚合物的凝胶时间达到最佳匹配状态...

MATERIALS FOR TRANSMISSION HALOGRAPHIC POLYMER DISPERSED LIQUID CRSYTAL GRATING WITH HIGH SPATIAL FREQUENCIES

Transmission halographic polymer dispersed liquid crsytal grating with high spatial frequencies(3000 lp/mm),abbrivrated as HF-THPDLC,was fabricated,and the material system was investigated.In order to get the HF-THPDLC grating with high diffraction efficiency and perfect surface morphology,the average functionality of the reaction system was determined first.Therefore,the diffusion time of the pre-polymer monomer and the liquid crystal,the nucleation time of the liquid crystal and the gelation time of the polymer are on the same order.Consequently,the perfect surface morphology was obtained and the scattering loss of the grating was reduced.Secondly,small monomer NVP was added into the reaction system of fabricating grating,and the optimum concentration was found.The addition of NVP enhanced the degree of phase separation and got perfect surface morphology as well as higher refractive index modulation.And accordingly the diffraction efficiency of HF-THPDLC grating was remarkably improved.Experimental results indicated that when the average functionality was 3.2 and NVP concentration was 10%,the optical properties of the HF-THPDLC grating were the best and the diffraction efficiency reached 78.3%.