Ultrashort optical pulses in two-level systems with Coulomb interaction and defects

The dynamics of an ultrashort optical pulse in an ensemble of two-level systems (in particular, in the presence of defects) is considered in the framework of the microscopic pseudospin formalism without limitation on the pulse power in the approximation of unidirectional propagation. The effective equations for the electric field amplitude and polarization of two-level systems are derived and solved numerically. Quasi-soliton modes of propagation of ultrashort optical pulses are revealed and the dependences on the macroscopic Hamiltonian parameters are analyzed. The effect of various types of defects on the propagation of ultrashort pulses is detected.