Transverse magnetic mode along THz waveguides with biased superlattices

We study the propagation of transverse magnetic modes arising from a waveguide consisting on a GaAs-based superlattice located at vacuum–dielectric interface. The transverse mode is generated by the ultrafast intersubband response of the superlattice subjected to a high-frequency electric field. The superlattice is also subjected to a homogeneous bias potential to get a biased superlattice with equipopulated levels. The heterostructure is analyzed through the tight-binding approximation, and considering the level broadening caused by different scattering processes (homogeneous and inhomogeneous broadening mechanisms). We pay special attention to the dispersion relations of the complex dielectric permittivity because of real and imaginary parts of this function play a key role in wide miniband superlattices.