Surface-Wave Coupling in Double Floquet Sheets Supporting Phased Temporal Wood Anomalies

TL;DR

This paper demonstrates how phase-controlled temporal modulation in double-layer systems can selectively excite and switch surface waves efficiently, enabling ultrafast control of surface modes.

Contribution

It introduces a semi-analytic transfer matrix formalism for time-modulated double-layer structures and shows how phase difference controls surface-wave excitation.

Findings

Phase difference enhances surface mode excitation

Efficient switching between modal channels

Full-wave simulations confirm theoretical predictions

Abstract

We investigate symmetry-selective surface-mode excitation in a general periodically time-modulated double-layer system, where the modulation of the two layers has a constant phase difference. By deriving a semi-analytic trans-fer matrix formalism of a Drude-dispersive double-layer structure with periodic time-modulation, we calculate the scattering amplitudes and the corresponding transmission coefficient. Our results show that the phase-difference between the modulation of the two sheets plays an essential role in significantly enhancing and selectively exciting either the even or odd surface mode with high efficiency. We verify our calculations with full-wave time-domain simulations, showing that efficient switching between the surface-wave excitation of the two distinct modal chan-nels can be achieved, even under illumination from a single off-resonant Gaussian pulse, by controlling the phase difference between the two modulations. Our results pave the way towards ultrafast, symmetry-selective mode excitation and switching via temporal modulation.