Flux Density through Guides with Microstructured Twisted Clad DB Medium

The paper deals with the study of flux density through a newly proposed twisted clad guide containing DB medium. The inner core and the outer clad sections are usual dielectrics, and the introduced twisted windings at the core-clad interface are treated under DB boundary conditions. The pitch angle of twist is supposed to greatly contribute towards the control over the dispersion characteristics of the guide. The eigenvalue equation for the guiding structure is deduced, and the analytical investigations are made to explore the propagation patterns of flux densities corresponding to the sustained low-order hybrid modes under the situation of varying pitch angles. The emphasis has been put on the effects due to the DB twisted pitch on the propagation of energy flux density through the guide. 1. Introduction Metamaterials are artificially designed mediums that owe unusual phenomena, such as reversal of Snell’s law and Doppler’s effect, negative reflection/refraction, and many others. These exotic features are basically due to the structures of materials rather than their compositions, and are used in many interesting applications, for example, cloaking, perfect lensing, and power confinement [1–4]. References [5, 6] describe negative index chiral metamaterial based on eight-crank molecule designed structure; homogeneous as well as isotropic behavior of chiral medium, based on the periodic inclusion of cranks, have been demonstrated. During the last couple of decades, complex structured guides have attracted the R&D community, primarily because of their varieties of potential applications that include optical sensing, integrated optics, and microwaves devices. The electromagnetic behavior of guides can be tailored by altering structural geometry, medium composition, and the nature of excited electromagnetic field. References [7–11] describe several forms of waveguide structures and their electromagnetic response. Reference [8] demonstrates wave propagation through chiral nihility metamaterial, a special class of chiral medium, in which the real part of permittivity and permeability simultaneously becomes zero, while its chirality remains nonzero. In the context of complex optical micro- and/or nanostructures, helical clad optical guides offer control over the dispersion behavior through suitable adjustments of the helix pitch angle [12–16]. Such helical forms or the twists can be written on fiber structures by the use of current advancements in nanotechnology. The usefulness of DB boundary conditions in the construction of spherical and cylindrical cloaks