Wideband Polarization Conversion with the Synergy of Waveguide and Spoof Surface Plasmon Polariton Modes

The ability to freely control the polarization of electromagnetic waves is of great significance, and state-of-the-art challenges include achieving efficient, wide-band polarization control with a relatively thin device in transmission geometry. To meet the challenge, this study combines slow waves (from spoof surface plasmon polariton modes) with fast waves (from waveguide modes) to handle orthogonal polarization components. Such a system can be quite thin, due to the strong dispersion between these two types of modes, with cancellation of the two nonlinearly dispersive modes yielding high-efficiency polarization conversion over a wide frequency range.