Zheng H Y, Jin X R, Park J W, Lu Y H, Rhee Joo Yull, Jang W H, Cheong H, Lee Y P
Department of Physics and Quantum Photonic Science Research Center, Hanyang University, Seoul 133-791, South Korea.
Opt Express. 2012 Oct 8;20(21):24002-9. doi: 10.1364/OE.20.024002.
Magnetic resonance is considered to be a necessary condition for metamaterial perfect absorbers, and dual-band absorbers can be composed of a pair of metallic layers with anti-parallel surface currents. We designed and fabricated a tunable dual-band perfect absorber based on extraordinary-optical-transmission (EOT) effect and Fabry-Perot cavity resonance. The idea and the mechanism are completely different from the absorber based on the near-field interaction. The important advantage of our structure is that we can switch a single-band absorber to a dual-band absorber by changing the distance between two metallic layers and/or incident angle. The peak originating from the EOT effect becomes significantly narrower, resulting in an increase of the Q-factor from 16.88 to 49. The dual-band absorber can be optimized to be insensitive to the polarization of the incident electromagnetic wave by slightly modifying the absorber structure.
磁共振被认为是超材料完美吸收体的必要条件，双频吸收体可由一对具有反平行表面电流的金属层组成。我们基于超常光学透射（EOT）效应和法布里-珀罗腔共振设计并制作了一种可调谐双频完美吸收体。其原理和机制与基于近场相互作用的吸收体完全不同。我们结构的重要优势在于，通过改变两个金属层之间的距离和/或入射角，能够将单频吸收体转换为双频吸收体。源自EOT效应的峰值显著变窄，品质因数从16.88提高到49。通过对吸收体结构进行微调，可将双频吸收体优化为对入射电磁波的偏振不敏感。
