Abstract-Unusual electromagnetic modes in space-time-modulated dispersion-engineered media

Nima Chamanara, Zoé-Lise Deck-Léger, Christophe Caloz, and Dikshitulu Kalluri

https://journals.aps.org/pra/accepted/eb07cY2dX7b18569c07917c062834bf82d647b861

We report on new electromagnetic modes in space-time modulated dispersion-engineered media. These modes exhibit unusual dispersion relation, field profile and scattering properties. They are generated by coupled codirectional space-time harmonic pairs, and occur in space-time periodic media whose constituent materials exhibit specific dispersion. Excitation of a slab of such a medium with subluminal modulation results in periodic transfer of energy between the incident frequency and a frequency shifted by a multiple of the modulation frequency, whereas superluminal modulation generates exponentially growing frequencies. These modes may find applications in optical mixers, terahertz sources and other optical devices.