Nano shell impact on Huygens’ metasurface dipolar resonances and optical response

Abstract

Due to several advantages over conventional devices for the control of electromagnetic (EM) radiation, the demand for metasurface utilization based on artificially engineered micro and nanostructures is boosted, especially in new generation devices. Among the metasurfaces family, there has been a growing interest in Huygens’ metasurfaces that are easy to fabricate due to their lower aspect ratio compared to their counterparts and also provide alternative electromagnetic radiation control by tuning the dipolar electric and magnetic resonances. In this study, an all-dielectric Huygens’ metasurface consisting of the high-refractive-index nano shells embedded in the low-refractive-index environment is designed and extensively investigated numerically and analytically in the near-infrared spectrum. By simply tuning the nano shell inner radius, the effects on the dipolar resonances are unveiled specific to the proposed design. To assess the EM wave interactions in the designed Huygens’ metasurface, an analytical model based on the coupled discrete dipole approach is applied for selected distinct cases of the designed metasurface. It is shown that the spectral position of the dipolar resonances can be detuned or tuned simultaneously depending on the structural parameter of the meta-atoms arranged in a periodic array. This study sheds light on the physics and abilities of the nano shell structure as a Huygens’ metasurface for the potential applications of metasurface-based light–matter interaction including imaging and sensing.