Oblique incidence and polarization effects in coupled gratings

Abstract

Oblique incidence and polarization orientation of the input beam have dramatic effects on the spectral response of coupled dielectric waveguide gratings. Coupled gratings with small periodic perturbations can be described as a problem of two coupled resonances at strictly normal incidence, but we find that the device involves four coupled resonances when oblique incidence and polarization effects are included in the analysis. Very small deviations from normal incidence change qualitatively the spectral response and four peaks are observed, whereas only two peaks are present at normal incidence. Polarization misalignments produce a decrease of the reflectance of the resonances at normal incidence, but a simultaneous shift of the spectral position of the peaks is observed at oblique incidence.

Design of narrow‐band dielectric frequency‐selective surfaces for microwave applications

“…Previous studies on DWGs reveal that very small deviations from normal incidence can change qualitatively the spectral response of this kind of structures [28], [38]. In Fig.…”

Surface-Impedance Formulation for Hollow-Core Waveguides Based on Subwavelength Gratings

“…Because of this, the field penetration depth in a HCG-HW cladding is significantly reduced compared to DBR or PhC based hollow-core waveguides, and consequently, its attenuation loss factor diminishes. In this case, surface-relief gratings have been chosen as high reflective structures for easy-of-fabrication purposes [25]. Thus, the proposed THz hollow-core waveguide consists of two reflecting surfacerelief subwavelength gratings that are periodic in the z direction and infinite in the y direction (see the figure inset in Fig.…”