  Different optical nanostructures containing both loss and gain components
attract ever-increasing attention as novel advanced materials and building
blocks for a variety of nanophotonic and plasmonic applications. Unique tunable
optical signatures of the so-called active metamaterials support their
utilizing for sensing, imaging, and signal processing on micro- and nanoscales.
However, this tunability requires flexible control over the metamaterials
parameters, which could be provided by involving a set of nonlinear
interactions. In this paper, we propose a method of governing ultrashort pulses
by varying the level of a population difference disorder in a random active
metamaterial. This enables to deliver three different interaction regimes:
self-induced transparency (low disorder), localization regime (moderate
disorder), and light amplification (strong disorder) corresponding to strongly
different light pulses speeds. Since this control could be realized via rather
plain tools, like simple pump tuning, the proposed disordered medium opens a
room of opportunities for designing peculiar active component for a whole set
of highly demanded optical applications.
