Extremely short and quasi-monochromatic electromagnetic solitons in a two-component medium

The propagation of extremely short (without high-frequency filling) pulses and nonresonant envelope solitons in a two-component medium comprising two-level atoms with substantially different quantum transition frequencies was studied. The dynamics of a pulse whose reciprocal time scale lay between these frequencies was shown to be described by the Kosevich-Kovalev equation, the one-way variant of which was the Konno-Kameyama-Sanuki equation. If the transition dipole moments of medium components were equal, the one-way equation became integrable. Soliton and soliton-like solutions to these equations were used to analyze pulse propagation regimes at various two-component medium initial states. The stability of these localized wave formations was analyzed. The possible existence of stable soliton-like pulses propagating in a nonequilibrium medium at group velocities exceeding the velocity of light in vacuum was discussed. (C) 2001 MAIK "Nauka/Interperiodica".