Broadband control of group delay using the Brewster effect in metafilms

TL;DR

This paper introduces a method to control electromagnetic wave group delay over broad frequencies using Brewster effect in metafilms, enabling large delays near resonance with high transmittance, and demonstrates stacking multiple metafilms for additive effects.

Contribution

The study develops a novel approach to achieve broadband group delay control using reflectionless metafilms based on the Brewster effect, verified through simulations and experiments.

Findings

Reflectionless metafilms exhibit near-unity transmittance across frequencies.

Total group delay in stacked metafilms is additive.

Experimental results confirm theoretical predictions.

Abstract

We propose and verify a method for controlling the frequency dependence of the group delay of electromagnetic waves over a broad frequency range using the Brewster effect in single-layer metamaterials with finite thickness, here referred to as metafilms. When the metafilm's reflectance vanishes regardless of the incident frequency, the group delay can be large near its resonance frequency while maintaining the transmittance close to unity regardless of the incident frequency. Furthermore, when several reflectionless metafilms are stacked together, the total group delay should be given as the sum of the individual group delays. In this study, we realize reflectionless metafilms by arranging the meta-atoms so that the Brewster effect occurs regardless of the incident frequency. We evaluate in numerical simulations and experiments the frequency dependence of the transmittance and of the group delay of a three-layer metamaterial composed of reflectionless metafilms with different resonance frequencies, and find that the total transmittance and group delay of this metamaterial agree respectively with the product of the transmittances and the sum of the group delays of the constituent metafilms.