Asymptotic theory of mode coupling in a spacetime periodic medium. I  Stable interactions
Abstract
An asymptotic theory, constituting an extension of existing coupled mode theory to any high order of interaction, is developed for plane waves in a spacetime periodic medium. Stable interactions are examined in the case where the phase velocity of the progressive modulating wave is less than the phase velocity of the EM wave traversing the unmodulated medium. Interactions of the fundamental wave progressing in the direction of the modulating wave are investigated, with the first four harmonics progressing in the reverse direction considered. Selfeffect and mutual effect introduced by the periodic inhomogeneity, and their effects in turn, are treated. Analytical formulas are derived for frequency shift and wavenumber; asymptotic results and numerical results are compared.
 Publication:

IEEE Proceedings
 Pub Date:
 July 1977
 Bibcode:
 1977IEEEP..65..996S
 Keywords:

 Asymptotic Methods;
 Coupled Modes;
 Electromagnetic Interactions;
 Periodic Variations;
 Plane Waves;
 SpaceTime Functions;
 Electromagnetic Interactions;
 Electromagnetic Wave Transmission;
 Frequency Shift;
 Inhomogeneity;
 Modulation;
 Perturbation Theory;
 Phase Velocity;
 Propagation Modes;
 Communications and Radar