Abstract:
Giant in-plane anisotropy can be exhibited by a finitely thick periodic multilayer comprising
bilayers of an isotropic noncentrosymmetric material and a non-dissipative isotropic medium of
negative permittivity, when a dc electric field is applied in the thickness direction. Compared to a
homogeneous layer of the noncentrosymmetric material with the same thickness as the periodic
multilayer, the latter exhibits an effective in-plane anisotropy that can be three orders larger in
magnitude. This enhancement gets more substantial at higher frequencies and is electrically controllable.
The incorporation of dissipation reduces the enhancement of the effective in-plane anisotropy,
which nevertheless remains significant. We expect the finitely thick periodic multilayer to be
useful as a polarization transformer or a modulator in the terahertz regime fully controllable via
external dc bias