Elliptical metallic rings-shaped fractal metamaterial absorber in the visible regime

R M H Bilal,M A Saeed,P K Choudhury,M A Baqir,W Kamal,M M Ali,A A Rahim

doi:10.1038/s41598-020-71032-8

Abstract

Achieving the broadband response of metamaterial absorbers has been quite challenging due to the inherent bandwidth limitations. Herein, the investigation was made of a unique kind of visible light metamaterial absorber comprising elliptical rings-shaped fractal metasurface using tungsten metal. It was found that the proposed absorber exhibits average absorption of over 90% in the visible wavelength span of 400–750 nm. The features of perfect absorption could be observed because of the localized surface plasmon resonance that causes impedance matching. Moreover, in the context of optoelectronic applications, the absorber yields absorbance up to ~ 70% even with the incidence obliquity in the range of 0°–60° for transverse electric polarization. The theory of multiple reflections was employed to further verify the performance of the absorber. The obtained theoretical results were found to be in close agreement with the simulation results. In order to optimize the results, the performance was analyzed in terms of the figure of merit and operating bandwidth. Significant amount of absorption in the entire visible span, wide-angle stability, and utilization of low-cost metal make the proposed absorber suitable in varieties of photonics applications, in particular photovoltaics, thermal emitters and sensors.

Highlights

Achieving the broadband response of metamaterial absorbers has been quite challenging due to the inherent bandwidth limitations
We investigate the effects of operating conditions and geometrical parameters on the spectral response of the proposed absorber, which involves the analyses of performance characteristics evaluating the figure of merit (FOM) and operational bandwidth (OBW)
In order to evaluate the prospective robustness of the proposed fractal metamaterial absorber (FMA), we study the influence of incidence obliquity on the performance of the same

Summary

Introduction

Achieving the broadband response of metamaterial absorbers has been quite challenging due to the inherent bandwidth limitations. Significant amount of absorption in the entire visible span, wide-angle stability, and utilization of low-cost metal make the proposed absorber suitable in varieties of photonics applications, in particular photovoltaics, thermal emitters and sensors. From the perspective of absorption bandwidth, the narrowband metamaterial absorbers covering the visible and infrared (IR) regimes find applications, such as thermal emission manipulation, nano-antennas, sensors, and resonators[28,29]. Such metamaterials exhibit the application of plasmonic resonance in medical imaging[33], photo thermal therapy[34] and biosensing toward environmental p rotection[35,36]. The two-dimensional (2D) materials have been greatly attracting as these open-up avenues for varieties of photonics-based applications – the feature basically due to strong absorption that happens because of their unique optical and electronic properties[37,38,39,40]

Methods

Results

Conclusion