Different regimes of ultrashort pulse propagation in disordered layered media with resonant loss and gain

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.