Handedness-dependent electromagnetic induced transparency in dielectric polymer-based 3D structures

Abstract

Electromagnetic induced transparency (EIT) is a quantum phenomenon, featuring strong dispersion at the transparent window in an absorption spectral region. In recent years, EIT-like behaviors have also been discussed in artificial nanostructures, where a transparent window emerges in an otherwise high reflection band. Up to date, many demonstrations are implemented based on all-dielectric metamaterials as the loss can be reduced compared to their metallic counterparts. However, studies are mostly presented based on high-refractive-index dielectrics, in which the choice of materials is limited at optical frequencies. In this study, we present a new strategy that enables handedness-dependent EIT in a lower refractive index dielectric material (n~1.5), which can be more widely implemented in polymer-based fabrication platforms. In the first part of the study, we numerically present the evolution of EIT response in a helix structure from high to low refractive indices. As the refractive index decreases from 3.5 to 1.5, the resonances are less pronounced and the EIT behavior cannot be maintained. Therefore, we show that by properly tailoring the geometrical parameters, the EIT response may emerge again without increasing the refractive index. In the second part of the study, we characterize the effect of substrate on the handedness-dependent EIT response of the helix structure. We show that the EIT performance is severely degraded since the dielectric helix has a refractive index close to the glass substrate. To resolve the issue, we present a rod-supported structure to effectively retrieve the EIT response. As EIT-based devices are widely used for sensors and nonlinear optics, our design which can be implemented on a polymer-based platform may broaden the horizon of applications in sensors and optoelectronics devices.