Longitudinal medium vibrations in dielectrics excited by ultrashort optical pulses

Summary form only given. We show in the present paper that the propagation of TM polarized ultrashort pulses in a two dimensional geometry, even though detuned very far from its resonance for transverse fields, shows the possibility of resonant matter-field interaction. Namely, the interaction of longitudinal fields with longitudinal medium vibrations. As we expect the longitudinal fields to be also present in three dimensional pulse propagation, our two dimensional investigation of the TM polarized pulses serves as a paradigm for an additional mechanism with the potential to modify the critical self-focusing of intense ultrashort pulses.