“π”型双频负折射率超材料

A “π-shaped”metamaterial with dual-band negative refraction index

基于有效媒质理论,设计了一种"π"型光频段电磁超材料.仿真结果表明,这种超材料能够在550.4THz和577.8THz 2个频率附近产生谐振,并且在谐振频率附近样品的介电常数和磁导率同时为负值;通过将"π"型单元排列成楔形结构,验证了电磁超材料的负折射性能;进一步的研究证实,这种超材料的电磁响应与前后"π"型结构之间的旋转角度密切相关.另外,这种"π"型电磁超材料具有较低的能量损耗,弥补了其他渔网结构损耗高的缺陷,同时也为设计可见光频段的多频电磁超材料提供了一种新模型.

In this paper,a kind ofπ-shaped visible electromagnetic metamaterial on the basis of effective medium theory is designed.The simulated results demonstrate that the proposed metamaterial can generate resonances around 550.4 THz and 577.8 THz,with the permittivity and permeability being negative simultaneously.The negative refraction performance of the metamaterial is confirmed by using a wedge-shaped array composed ofπ-shaped unit cells.Further simulations reveal that the electromagnetic responses of the proposed metamaterial are closely related with the twist angle between the front and backπ-shaped patterns.This kind ofπ-shaped metamaterial exhibits low loss feature,which overcomes the drawback of high losses existing in some other fishnet metamaterials and also provides a new model for designing multiband visible electromagnetic metamaterials.