Modal analysis and solution of electromagnetic wave propagation in cholesteric liquid crystal cells

Abstract

Cholesteric Liquid Crystals (Ch-LC) are anisotropic and inhomogeneous materials with intriguing and useful properties in the visible region of the electromagnetic spectrum. In this paper, we use eigenmode analysis to obtain the supported field expressions in a thin, homogeneous sub-layer of the Ch-LC cell; the liquid crystal is made of multiple sub-layers. The cell is sandwiched between layers of dielectric and is excited by an elliptically polarized plane wave at an oblique incidence. The governing field expressions in the dielectric layers are also obtained using eigenmode analysis. A mode-matching technique (MMT) is then employed to enforce the continuity of the tangential electric and magnetic fields at the interface of two neighboring layers, thus, resulting in a matrix system representative of the problem at hand. Solution of the linear system of equations yields the reflection and transmission coefficients on the two principal planes as well as the expansion coefficients for the modal fields inside the Ch-LC and the dielectric layers. The underlined formulation is verified by comparing results to the open literature.