电可调谐的聚合物液晶光子晶体

Electrically switchable polymer dispersed liquid crystal photonic crystals

设计了一个无顶的(top-cut)六角棱镜,高h为3.73 cm,侧面与底面夹角α为66°。利用此棱镜和光全息刻蚀的方法,在光抗材料上制作了对称六角结构、蜂窝结构和椭圆柱非对称等结构的光子晶体(PhC);并且在聚合物分散液晶(PDLC)材料上制作了大面积电可调谐的PhC结构。PhC的理论干涉模式和实验制作结构相比较,结果吻合得非常好。研究了PhC的远场衍射模式和电转换特性,对称的六角衍射模式更好地揭示了PhC的六角结构。晶体结构中液晶微滴的尺寸最小可到10 nm,直流转换电压最小达到13.3 V/μm。

A top-cut hexagonal prism （TCHP） was designed with a height h = 3.73 cm and a cross angle α = 66° between side face and the base. By using the TCHP and holographic lithography, various photonic crystals （PhCs） were fabricated including symmetrical hexagonal structure, honeycomb structure and asymmetrical structures with elliptical rods in photo-resist film. Large area of electrically switchable PhCs were also obtained in polymer dispersed liquid crystal （PDLC） film. A good agreement is obtained for PhC structures between theoretical modeling and experimental results. Furthermore, far-field diffraction patterns and electrical switching characteristics were also investigated. The smallest droplets of liquid crystals is 10 nm. The switching voltage can be decreased to 13.3 V/μm.