Self-induced transparency pulses propagating in a random medium embedded in a two-level system can transfer energy to localized Anderson states. This allows the onset of two-level laserlike action.
Self-induced transparency effects are examined in an absorbing medium having degenerate optical transitions. Undistorted propagating light pulses exist under restrictive conditions for $j\ensuremath{\rightleftharpoons}j$ transitions (j>0) and for 0 \ensuremath{\rightleftharpoons} 1 and $\frac{1}{2}\ensuremath{\rightleftharpoons}\frac{3}{2}$. Pulses which propagate without energy loss for any transition ${j\ensuremath{\rightleftharpoons}j}^{\ensuremath{'}}$ also include zero-degree pulses defined as $\ensuremath{\int}\mathcal{E}(z,t)dt=0$.
Self-action effects in two copropagating q-Gaussian laser beams within Kerr nonlinear media featuring electromagnetically induced transparency: role in slow light
We consider a one-dimensional photonic crystal embedded in a two-level medium with various degrees of disorder, such that the tail of localized states in the forbidden gap is resonant with self-induced transparency pulses, which can propagate in the absorbing system. We theoretically and numerically predict that the SIT pulse not only is slowed down by the disorder, but, at high scattering strengths, it is trapped by coupling with Anderson states located in proximity of the cavity surface. We develop a perturbative analysis to address the role of the random perturbation on the propagation of a 2π pulse in a two level medium.
Self-induced transparency (SIT) pulses induce a traveling population inversion in two-level atoms. As a rule, the active medium in which the soliton travels has to be homogeneous. Here, we study the effect of a spatially disordered modulation in the refractive index profile that may lead to Anderson localizations. The interplay between the ultrashort SIT pulse, a nonlinear effect, and this kind of disorder-induced mode exhibits intriguing features. Once the SIT pulse is confined in the spatially confined regions, they act as closed cavities for the SIT population inversion. A positive optical feedback mechanism can be thus activated and, as a result, a two-level laserlike emission can be obtained.