New type of lenses based upon left-handed materials
  New type of lenses which are a slab of a left-handed material embedded into a regular material is proposed. These two materials should have equal refractive indices. Lenses with a focal length larger than the width of the slab can be constructed. These lenses should be easier to make than the well known Veselago lens, because the materials of the Veselago lens should obey an additional matching condition. Lenses of new type have multiple foci and might be useful for the 3D imaging. 
A. L. Pokrovsky, A. L. Efros