Propagation of Short Pulses in Dielectric Media

For the first time, generalization of theoretical and experimental works on pulse propagation in different media (including the active ones) was given by L. A. Vainshtein 1976. Since then a lot of works have appeared, wherein such new classes of active media as the ferroelectric, semiconductive and superconductive ones are described. Thin films manufactured from active medium materials amplify electromagnetic waves (EMW) while they propagate through the films. EMW propagation through nonlinear films in antenna systems is also investigated. In survey, short pulse propagation is studied with the use of special space-time Green´s function proposed by the author. On the same basis, Vainshtein has studied active media, wherein propagating signals are amplified due to the electron non-balanced energy state in atoms and molecules. To some extent, his results can be also used when studying propagation of short pulses in other active media, but in this case, methods of work have to be essentially changed. In the paper, the character of changes is illustrated on the example of ferroelectric media