ABSTRACT
This chapter investigates the transmission and reflection properties of a resonant nonlinear medium when the incoming wave is a short pulse, generally shorter than the relaxation times of the atoms in the medium. It shows that if the lifetime of the macroscopic polarization is long enough, and neither the incident field nor the relaxation processes reduce it, then the field originating from this polarization gives rise to effects which may be called cooperative reflection and transmission. The chapter considers the resonant reflection from the surfaces of the inverted medium of waves propagating inside the medium. It uses this effect to explain the synchronization of the counter-propagating pulses in super-radiance which has been observed in KCl:O2– [FSS84a]. There are several proposals to explain why this synchronization of super-radiance appears in solids.
