Ultranarrowband perfect terahertz absorber based on a metal- and insulator-stacked structure

• DOI: 10.1364/josab.33.002602
• Publication Date: 2016-11-23T16:38:03Z
• Authors: Jing Nie; Hu-Quan Li
• Keywords: Metal-insulator-metal; Absorbance; Narrowband; Terahertz gap

Electromagnetic field absorbers with ultranarrow relative bandwidth (<1%) and extremely high peak absorbance (>90%) are a challenge in terahertz frequency. In this paper, we propose an insulator-metal-insulator-metal stacked structure nearly unity (∼99%) 0.77% as ultranarrowband perfect absorber. Even though the composite contains reflective metal layers, however, thanks to introduction of top insulator, can tunnel through upper gold film at some functional tunneling bands. As result, energy Fabry–Perot resonance metal-insulator-metal substructure is strongly absorbed due enhancement effect. The absorption (>99%) width properties make design promising devices such absorbers, filters, narrowband emitters, etc.