Guided Modes in a Slab Wayeguide with Air Core Layer and Left-handed Materials Claddings

A symmetric three-layer slab waveguide with air as core and anisotropic left-handed materials as claddings is investigated. Some dispersion equations are derived and corresponding dispersion curves are plotted, respectively. From these curves, with the increase of the waveguide thickness, their operating frequencies become widely such as surface TE0 mode, surface TE1 mode and oscillating TM1 mode. However, for the surface TM0 mode, its dispersion curves move down and operating frequencies get narrow, and for oscillating TE1 mode, its dispersion curves move to left and cutoff frequencies become less. Since all experimental realization of left-handed materials have narrow bands, thus, these new features may give us a direction to increase band width.