Bilal R M H, Saeed M A, Choudhury P K, Baqir M A, Kamal W, Ali M M, Rahim A A
Faculty of Electrical Engineering, Ghulam Ishaq Khan Institute of Engineering Sciences and Technology, Topi, 23640, Pakistan.
Division of Electronics and Electrical Engineering, Dongguk University, Seoul, 04620, Republic of Korea.
Sci Rep. 2020 Aug 20;10(1):14035. doi: 10.1038/s41598-020-71032-8.
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.
由于固有的带宽限制，实现超材料吸收器的宽带响应一直颇具挑战性。在此，对一种独特的可见光超材料吸收器进行了研究，该吸收器由使用钨金属的椭圆环形分形超表面组成。研究发现，所提出的吸收器在400 - 750纳米的可见波长范围内表现出超过90%的平均吸收率。由于导致阻抗匹配的局部表面等离子体共振，可以观察到完美吸收的特征。此外，在光电应用方面，即使横向电极化的入射角在0° - 60°范围内，该吸收器的吸光度仍可达约70%。采用多次反射理论进一步验证了吸收器的性能。发现所获得的理论结果与模拟结果密切吻合。为了优化结果，从品质因数和工作带宽方面对性能进行了分析。在整个可见范围内的大量吸收、广角稳定性以及低成本金属的使用，使得所提出的吸收器适用于各种光子学应用，特别是光伏、热发射器和传感器。
