Gain control and diffraction-managed solitons in metamaterials

The question of whether stable, active metamaterials can be created is addressed, both through a discussion of absolute instability and an analysis of a transmission line that produces dispersion analogous to that of the familiar split-ring resonator/wire-based metamaterial. The gain is introduced using negative conductance diodes and it is shown that the frequency bandwidth controls the stability window. The diodes are located as lumped elements in the unit cell. It is demonstrated that the production of an, active, negative phase (left-handed) frequency window, with spatial amplification is possible. The paper then goes on to assume that since loss can be controlled in this way special types of solitons can be created from phase and loss compensation and they could be the basis of future computational devices. The candidates selected are diffraction-managed spatial solitons and their basic properties are displayed numerically.