Frequency Dependence Effective Refractive Index of Meta\u2013Materials by Effective Medium Theory

In this present communication we studied the frequency dependenceof the effective electromagnetic parameters of left-handed and relatedmeta-materials (NIMs) of the split ring resonator (SRR) and wire type.By varying the width of inserted material as well as the host material,we also calculate the effective parameters of NIM like effectivepermittivity and effective permeability. Using these parameters, wecalculate the effective refractive index and impedance of theconsidered medium. Our results reveal that the negative index ofmaterials can be achieved when the thickness of the host materialsshould equal to the thickness of the inserted materials

Tunable transmission of a nematic liquid crystal as defect in a 1D periodic structure of dielectric materials by orientation and re-orientation of liquid crystal molecules

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