Ultra-broadband metamaterial absorbers from long to very long infrared regime

• Published in: Light, science & applications science & applications, 2021-07, Vol.10 (1), p.138-138, Article 138
• Main Authors: Zhou, Yu, Qin, Zheng, Liang, Zhongzhu, Meng, Dejia, Xu, Haiyang, Smith, David R., Liu, Yichun
• Format: Article
• Language: English
• Subjects: 142/126; 639/624; 639/624/399/1015; Applied and Technical Physics; Atomic; Bandwidths; Classical and Continuum Physics; Composite materials; Experiments; Lasers; Light; Molecular; Optical and Plasma Physics; Optical Devices; Optics; Photonics; Physics; Physics and Astronomy; Silicon dioxide; Silicon nitride
• ISSN: 2047-7538; 2095-5545; 2047-7538
• DOI: 10.1038/s41377-021-00577-8

Broadband metamaterials absorbers with high absorption, ultrathin thickness and easy configurations are in great demand for many potential applications. In this paper, we first analyse the coupling resonances in a Ti/Ge/Ti three-layer absorber, which can realise broadband absorption from 8 to 12 μm. Then we experimentally demonstrate two types of absorbers based on the Ti/Ge/Si 3 N 4 /Ti configuration. By taking advantage of coupling surface plasmon resonances and intrinsic absorption of lossy material Si 3 N 4 , the average absorptions of two types of absorbers achieve almost 95% from 8 to 14 μm (experiment result: 78% from 6.5 to 13.5 μm). In order to expand the absorption bandwidth, we further propose two Ti/Si/SiO 2 /Ti absorbers which can absorb 92% and 87% of ultra-broadband light in the 14–30 μm and 8–30 μm spectral range, respectively. Our findings establish general and systematic strategies for guiding the design of metamaterial absorbers with excellent broadband absorption and pave the way for enhancing the optical performance in applications of infrared thermal emitters, imaging and photodetectors. Ultra-broadband metamaterials absorbers with high absorption, ultrathin thickness and easy configurations are designed and demonstrated, which pave the way for enhancing the optical performance in applications of infrared thermal emitters, imaging and photodetectors.