Mechanically tuned cholesteric elastomer waveguide slab

Abstract

In this research, a planar waveguide whose core is a cholesteric liquid crystalline elastomer whose helical axis is perpendicular to its planar boundaries, is studied. The electrodynamics equations are established, together with the constitutive equations. The mechanical stress is tuned through elastic deformations in the parallel direction along the helix axis, in order to control the propagation parameters. The resulting equations system is solved numerically by assuming the guide to be surrounded either by air or vacuum. The propagation parameter and the ratio between the magnetic and electrical modes are obtained as a function of frequency, which provides the band structure of the aforementioned modes. The amplitudes of the profiles of the electromagnetic fields and the Poynting vector distributions are also sought as a function of position. Finally, the mixing of transverse electric and magnetic modes to generate new eigenmodes and their conditions for propagation within the waveguide, are also studied.