Enhancing the resolution of hyperlens by the compensation of losses   without gain media
  We present a method to improve the resolution of available hyperlenses in the literature. In this method, we combine the operation of hyperlens with the recently proposed plasmon injection scheme for loss compensation in metamaterials. Image of an object, which is otherwise not resolvable by the hyperlens alone, was reconstructed up to the minimum feature size of one seventh of the free-space wavelength. 
Xu Zhang, Wyatt Adams, Mehdi Sadatgol, and Durdu \"O. G\"uney
physics.optics