Enhancement of group velocity via homogenization: isotropic and anisotropic dielectric scenarios

Under certain circumstances, the magnitude of the group velocity in a homogenized composite material (HCM) can exceed that of the group velocity in its constituent materials. An enhancement in the magnitude of group velocity in isotropic as well as anisotropic dielectric HCMs is predicted by the application of the Bruggeman formalism for the homogenization of two constituent dielectric materials, one of which is characterized by a relatively large permittivity and relatively small frequency dispersion as compared with the other constituent material. Group-velocity enhancement is sensitively dependent upon the shape and orientation of the constituent particles.