Broadening Reflective Spectrum by Polymer Disposition
Based on the analytic expression of electromagnetic field solution of helical symmetric dielectric material, the paper presents the relationship between spectral reflectivity and birefringence of chiral liquid crystal, and the blue shift of Bragg reflection in the condition of oblique incidence. The theoretic results indicated that: 1) if birefringence of liquid crystal greater than 0.2 and thickness of liquid crystal layer reaches to 3 micrometers, the liquid crystal layer will reflect more than 90％ of incident light; 2) to reflect whole visible spectrum by Bragg reflection of the plane state of liquid crystal, it needs birefringence of liquid crystal to exceed 0.6; 3) when incidence angle inclines to 60 degree from normal direction, blue shift of reflective spectrum of chiral liquid crystal will reach to 100 nm. As birefringence of commercial available chiral liquid crystal is about 0.2, it needs to deposit polymer film by phase separation process in the internal surfaces of liquid crystal cell besides preparation of polymer network in liquid crystal. Combine the polymer network with the mountainous roughness on glass substrates, which tilt the axes of chiral liquid crystal, Bragg reflectance spectrum expands. Experiments demonstrated that Bragg reflection spectrum by chiral liquid crystal was increased from 80 nm to more than 120 nm, and contrast keeps to 4 : 1 by introduce both polymer network and sagging structure on surface of the cell.
Reflective Spectrum Chiral Liquid Crystal Cholesteric Nanometer Particle Network
Ziqiang Huang Wenjun Yang Jimin Wang
Opto-Electronic Information School, University of Electronic Science and Technology of China, Chengdu 610054, China
国际会议
上海
英文
123-127
2007-03-12（万方平台首次上网日期，不代表论文的发表时间）