Transmission Properties of TE Surface Wave Mode in Asymmetric Metal Stripe Arrays on Low-index Substrate Coating with High-index Dielectric Layers

It is well-known that only transverse magnetic (TM) waves can excite surface plasmons on the metal surface. However, with a high-index dielectric layer coated on the metal surface, the TE surface wave modes can be controlled similarly to the surface plasmon in subwavelength scale. Here using the finite difference time domain method, the transmission properties of TE surface wave modes in asymmetric metal stripe arrays on low-index substrate coating with high-index dielectric layers, are numerically simulated and double fano-resonance is present in the spectrum which lead to relatively narrow spectral line shape. To investigate the double fano resonant modes, transmission spectra with various asymmetric widths of the metal stripes in a cell are calculated. It is observed that the transmittance of the resonant dips can be modulated by increasing the difference between the asymmetric widths of metal stripes. the double fano resonance phenomenon disappeared when the widths of the metal stripes in a cell are symmetry. This work has potential applications in high sensitive sensing, filtering, light-matter interaction and so on.