An infrared energy harvester based on radar cross-section reduction of chiral metasurfaces through phase cancellation approach

Muhammad Amin,Thamer S Almoneef,Omar Siddiqui

doi:10.1038/s41598-021-90886-0

Muhammad Amin, Thamer S Almoneef + Show 1 more

Open Access

https://doi.org/10.1038/s41598-021-90886-0

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Abstract

Conventional metasurface absorbers rely on high dissipation losses by incorporating lossy materials. In this paper, we propose a novel mechanism of absorption based on phase cancellation of polarization states of scattered fields emerging from adjacent L-shaped chiral meta-atoms (unit cells). A linearly polarized wave forms helicoidal currents in each meta-atom leading to diagonally polarized radiated waves. When phase cancellation is employed by reorienting four such meta-atoms in a supercell configuration, contra-directed chiral currents flow in adjacent cells to cancel all the radiated fields in far-field region leading to a minimal broadside radar cross-section. From the reciprocity, the currents that are induced in the meta-atoms produce a null towards the incident direction which can be utilized for infrared energy harvesting. Full wave electromagnetic simulation indicates near perfect resonant absorption around 52.2 THz frequency. Enhanced bandwidth is shown by adding smaller resonators inside the supercell in nested form leading to dual band absorption at 45.2 THz and 53.15 THz.

Highlights

Conventional metasurface absorbers rely on high dissipation losses by incorporating lossy materials
With the recent advancement in nanotechnology, the optical rectennas are being considered as strong candidates for future solar energy harvesting, in the infrared spectrum[19,20,21]
We show by full-wave simulations a significant reduction of radar cross-section (RCS) and electromagnetic energy absorption of all polarizations in the spectral range of 40 to 60 THz

Summary

Introduction

Conventional metasurface absorbers rely on high dissipation losses by incorporating lossy materials. With the recent advancement in nanotechnology, the optical rectennas are being considered as strong candidates for future solar energy harvesting, in the infrared spectrum[19,20,21]. Single resonator elements such as dipole, bow-tie and spiral antennas have been suggested for energy harvesting in the visible and infrared s pectra[18,22,23]. By adjusting the phases of adjacent unit cells of a metasurface and by exploiting the plane wave expansion, the incident wavefront has been manipulated in exciting novel applications such as Fresnel reflectors[47,48], beam steering[49] and carpet cloaking of objects[50,51]. The phase control have been digitally encoded by employing switchable unit cells to efficiently manipulate the wavefront of scattered electromagnetic waves[52,53]

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