Singh Pawan, Thapa Khem B, Kumar Narinder, Kumar Devesh
Department of Physics, School for Physical and Decision Sciences Babasaheb Bhimrao Ambedkar University, Lucknow, India.
Eur Phys J E Soft Matter. 2018 Sep 3;41(9):100. doi: 10.1140/epje/i2018-11710-0.
In this paper, we investigate tunable transmission characteristics of a one-dimensional periodic structure (1DPS), designed with periodic dielectric materials containing a nematic liquid crystal (NLC) as a defect layer, on the basis of orientation and re-orientation of LC molecules. The nonlinear differential equation for the director of the liquid crystal under the light field is solved numerically. The relation between the liquid crystal director and the intensity of the electromagnetic wave (EMW) is derived. Transmittances of the liquid crystal defect layer in the 1DPS are calculated with the variation of the intensity of the incident wave and liquid crystal director tilt angles. By varying the director tilt angle of the liquid crystal molecules as well as the incident angle of the EMW, the shifting of the transmitted defect mode wavelengths is studied. Such study is helpful to understand how orientation and reorientation of the molecules affect the transmittance of the considered periodic structure when the EMW interacts with an embedded liquid crystal as a defect layer in the 1DPS of dielectric materials. Such photonic structure of dielectric materials with the liquid crystal layer as a defect layer can be used to fabricate bistable switches, optical filters, feedback lasers, etc.
在本文中，我们基于液晶（LC）分子的取向和重新取向，研究了一种一维周期结构（1DPS）的可调谐传输特性，该结构由包含向列型液晶（NLC）作为缺陷层的周期性介电材料设计而成。对光场下液晶指向矢的非线性微分方程进行了数值求解。推导了液晶指向矢与电磁波（EMW）强度之间的关系。计算了1DPS中液晶缺陷层的透过率随入射波强度和液晶指向矢倾斜角的变化情况。通过改变液晶分子的指向矢倾斜角以及EMW的入射角，研究了透射缺陷模式波长的移动。这样的研究有助于理解当EMW与作为介电材料1DPS中缺陷层的嵌入液晶相互作用时，分子的取向和重新取向如何影响所考虑的周期结构的透过率。这种以液晶层作为缺陷层的介电材料光子结构可用于制造双稳态开关、光学滤波器、反馈激光器等。
