Constant Intensity Supermodes in Non-Hermitian Lattices

We study the existence of a novel class of waves, with constant intensity (CI) in coupled non-Hermitian photonic systems. These generalized plane waves exist only in optical structures that are composed of gain and loss (in both linear and nonlinear domains). In the framework of coupled mode theory, we examine the properties of such supermodes in finite waveguide lattices. In particular, CI-supermodes with periodic, localized, and disordered phases in finite chains of optical elements are considered in detail. Extensions to the nonlinear regime and the connection to the continuum limit are also studied.