Pulse propagation and gain dynamics in two-component media

A.V Andreev, Sergei Sheetlin

Anatoli V. Andreev

Abstract : The mathematical algorithms and programs for the study of the resonant light-matter interactions in the multi-component and multilevel media and photonic bandgap structures have been developed. The optimal component distribution in the two-component media have been found to get a pulse of a superradiative emission of the highest intensity. The mathematical algorithms and programs for the study of the femtosecond pulse propagation in an extended medium of the two-level atoms have developed. The regime of the inversionless superradiance in the two-component superradiative medium has been investigated. The theory of the superradiance by an ensemble of the two-level atoms embedded in the dielectric host was developed. It was shown that the near dipole-dipole interaction of dense collection of two-level atoms is enhanced by the presence of the host material, decreasing the pulse temporal width and increasing the peak pulse intensity of superradiative emission. The theory of nonlinear light-matter interaction in multidimensional resonant photonic crystals under Bragg diffraction condition has been developed. It was obtained the analytical and numerical solutions describing the novel kinds of nonlinear solitary waves: the Laue soliton, O-field, propagating and standing gap solitary waves. It has been described the spatio-temporal nonlinear dynamics of coherent field in periodic resonant structures with arbitrary modulation of atomic density and gain gratings.

А. В. Андреев, P. V. Polevoy

Alvin Katz, R. R. Alfano

Li‐Gang Wang, Nian-hua Liu, Qiang Lin +1 more

The propagation of pulses through dispersive media was investigated by solving Maxwell's equations without any approximation. It was demonstrated that the superluminal or subluminal pulse propagation originates essentially from the interference of the different frequency components of the pulse. The coherence of the different frequency components plays an important role in superluminal propagation. When the pulse becomes partially coherent, the propagation changes from superluminal to subluminal. Since superluminality always exists as long as the spectrum of the coherent pulse is within the anomalously dispersive region whatever the shape of the pulse is, such a coherent pulse must be transmitted superluminally.

Andrzej Raczyński, Jarosław Zaremba, Sylwia Zielińska‐Raczyńska

Simultaneous propagation of two probe pulses in a medium of four-level atoms irradiated by three control fields is studied. The double Λ configuration has been closed by a fifth field, coupling the lower levels. It is shown that the propagation can be described in terms of four modes characterized by particular effective susceptibilities, which have absorption or gain peaks and transparency windows. For incoming one-peak pulses, multipeak spectra are built during the propagation including a few components of well-defined frequencies. They evolve along the sample with some of their spectral components being transmitted, absorbed, or amplified.