Guided modes in slab waveguides with negative index cladding and substrate

In this work, three normalized parameters are used to study the dispersion characteristics of three different asymmetric slab waveguide structures. Each structure contains at least one layer made of left-handed material (LHM). The first structure comprises a LHM cladding layer, the second contains a LHM substrate layer, and the third has a LHM cladding and substrate. The results show that the dispersion characteristics of these structures differ from conventional guided waves in waveguide structures comprising right-handed materials. A number of unusual properties are observed including the dispersion characteristics of the fundamental mode for the first structure is different for different μc and μs. The fundamental mode exists and can only propagate within a small frequency range in the second structure. In the third structure, the fundamental mode does not exist whereas the first-order mode exists in a narrow frequency range. No propagation modes in some frequency ranges is observed which enables the structure to behave as a bandpass filter.