Influence of the refractive index cladding on guided modes in a negative-index slab waveguide

This paper tackles the wave propagation along a slab waveguide composed of a left handed material (LHM) and surrounded by conventional media. We predict that such a waveguide can support symmetric modes in such a symmetric structure. We study the dispersion relation of found modes and the associated energy flow. The effect of refractive index cladding is investigated on dispersion curves and energy flow. We numerically show that the characteristic modes of the energy flow and the domain of the existence of the mode are significantly changed and can be controlled by varying the refractive index of the linear medium.