Light amplification in zero-index metamaterial with gain inserts.

The concept of light amplification in a system of zero-index metamaterial with gain inserts is studied. We demonstrate that the radiation from a point source embedded in the system can be effectively amplified and the net gain is independent of the positions of gain inserts and the source. We further investigate how the net gain grows with the imaginary part of the inserts' permittivities and find that it saturates when the imaginary part is sufficiently large. It is also shown that the efficiency of amplification is significantly reduced when lossy inserts are introduced into the system. [ABSTRACT FROM AUTHOR]