Title: Giant Field Enhancement in Longitudinal Epsilon Near Zero Films,
Abstract: We report that a longitudinal epsilon-near-zero (LENZ) film leads to giant
field enhancement and strong radiation emission of sources in it and that these
features are superior to what found in previous studies related to isotropic
ENZ. LENZ films are uniaxially anisotropic films where relative permittivity
along the normal direction to the film is much smaller than unity, while the
permittivity in the transverse plane of the film is not vanishing. It has been
shown previously that realistic isotropic ENZ films do not provide large field
enhancement due to material losses, however, we show the loss effects can be
overcome using LENZ films. We also prove that in comparison to the (isotropic)
ENZ case, the LENZ film field enhancement is not only remarkably larger but it
also occurs for a wider range of angles of incidence. Importantly, the field
enhancement near the interface of the LENZ film is almost independent of the
thickness unlike for the isotropic ENZ case where extremely small thickness is
required. We show that for a LENZ structure consisting of a multilayer of
dysprosium-doped cadmium oxide and silicon accounting for realistic losses,
field intensity enhancement of 30 is obtained which is almost 10 times larger
than that obtained with realistic ENZ materials