Designing Broadband Absorbers Based on Dielectric-Metal Multilayer

作者：Kan, Yin Hui; Zhao, Chang Ying^*; Fang, Xing

来源：Journal of Engineering Thermophysics, 2018, 39(9): 2018-2023.

• Absorber
• Admittance analysis
• Broadband
• Broadband absorbers
• Metal multilayers
• Spectral absorptions
• Topological transitions
• Visible and near infrared

In this paper, we propose a method to design broadband near-perfect absorbers consisting of a periodic dielectric-metal multilayer. In the method, the Bloch theorem and optical topological transition (OTT) of iso-frequency surfaces are employed to manipulate the start and end of the near-perfect spectral absorption band, respectively. We design and fabricate a broadband near-perfect absorber utilizing the proposed method. The average absorption of the designed absorber is about 95% in the focused visible and near-infrared range (0.4∼2 μm). Moreover, admittance analyses are employed to reveal the mechanism of the near-perfect absorption. By increasing the number of periods of the dielectric-metal layer gradually, the admittance change towards matching the free space admittance. This lithography-free near-perfect absorber is promising for solar energy harvesting, radiative cooling, and thermal imaging.

• 出版日期2018
• 单位上海交通大学