Multifunctional Cascaded Metamaterials: Integrated Transmitarrays

TL;DR

This paper introduces a novel concept of multifunctional cascaded metasurfaces that perform different electromagnetic functions at various frequencies, enabling advanced wave control with transparency outside operational bands.

Contribution

It presents the design and experimental validation of transmitarrays and cascaded metasurfaces that achieve multiple functionalities across different frequencies, expanding the capabilities of engineered electromagnetic materials.

Findings

Designed transmitarrays for wavefront shaping and anomalous refraction.

Successfully tested the cascaded metasurfaces experimentally.

Demonstrated multifunctionality at different frequencies with transparency outside the operational band.

Abstract

Control of electromagnetic waves using engineered materials is very important in a wide range of applications, therefore there is always a continuous need for new and more efficient solutions. Known natural and artificial materials and surfaces provide a particular functionality in the frequency range they operate but cast a "shadow" and produce reflections at other frequencies. Here, we introduce a concept of multifunctional engineered materials that possess different predetermined functionalities at different frequencies. Such response can be accomplished by cascading metasurfaces (thin composite layers) that are designed to perform a single operation at the desired frequency and are transparent elsewhere. Previously, out-of-band transparent metasurfaces for control over reflection and absorption were proposed. In this paper, to complete the full set of functionalities for wave control, we synthesize transmitarrays that tailor transmission in a desired way, being "invisible" beyond the operational band. The designed transmitarrays for wavefront shaping and anomalous refraction are tested numerically and experimentally. To demonstrate our concept of multifunctional engineered materials, we have designed a cascade of three metasurfaces that performs three different functions for waves at different frequencies. Remarkably, applied to volumetric metamaterials, our concept can enable a single composite possessing desired multifunctional response.