%0 Journal Article
%T Fundamental limitations to gain enhancement in periodic media and waveguides
%A Jure Grgi£¿
%A Johan Raunkj£¿r Ott
%A Fengwen Wang
%A Ole Sigmund
%A Antti-Pekka Jauho
%A Jesper M£¿rk
%A N. Asger Mortensen
%J Physics
%D 2012
%I arXiv
%R 10.1103/PhysRevLett.108.183903
%X A common strategy to compensate for losses in optical nanostructures is to add gain material in the system. By exploiting slow-light effects it is expected that the gain may be enhanced beyond its bulk value. Here we show that this route cannot be followed uncritically: inclusion of gain inevitably modifies the underlying dispersion law, and thereby may degrade the slow-light properties underlying the device operation and the anticipated gain enhancement itself. This degradation is generic; we demonstrate it for three different systems of current interest (coupled resonator optical waveguides, Bragg stacks, and photonic crystal waveguides). Nevertheless, a small amount of added gain may be beneficial.
%U http://arxiv.org/abs/1202.4911v2