Local field effects induced by near-dipole-dipole interaction in optically dense and resonant medium

The interactions between an ultrashort intense pulse and a dense resonant medium with local-field effects induced by near-dipole-dipole interaction were investigated. According to the semi-classical theory of light-matter interaction, the modified Bloch equations were established with near-dipole-dipole interactions in an optically dense two-level medium, and an accurate and efficient fourth-order Runge-Kutta method was applied for solving the equations. The numerical results show that, during the transient coherence, the evolutions of Bloch vectors and the final state of inversion are strongly modulated by the local-field effects. Furthermore, two modulation schemes of Bloch vectors in dense two-level media were proposed.