Strong Purcell effect in anisotropic $\varepsilon$-near-zero   metamaterials
  We theoretically demonstrate the strong Purcell effect in $\varepsilon$-near-zero ultra-anisotropic uniaxial metamaterials with elliptic isofrequency surface. Contrary to the hyperbolic metamaterials, the effect does not rely on the diverging density of states and evanescent waves. As a result, both the radiative decay rate and the far-field emission power are enhanced. The effect can be realized in the periodic layered metal-dielectric nanostructures with complex unit cell containing two different metallic layers. 
A.V. Chebykin, A.A. Orlov, A.S. Shalin, A.N. Poddubny, and P.A. Belov
physics.optics cond-mat.mes-hall