Guided modes in a planar anisotropic biaxial slab with partially negative permittivity and permeability

We have investigated the guidance conditions for both bulk and surface modes in a anisotropic biaxial slab whose permittivity and permeability tensors can be partially negative under the excitation of a two-dimensional line source. We have shown that such guidance conditions will vary greatly with the change of the tensor components. We also show that infinite bulk modes are excited under some specific conditions in the anisotropic slab, unlike the case in the traditional dielectric waveguide. An efficient graphical method has been proposed to determine the propagation constants of the guided modes in the anisotropic slab. (C) 2005 American Institute of Physics.