光波段多频负折射率超材料

从光波段圆孔形双鱼网结构的负折射材料模型出发，采用基于有限积分技术的CST软件系统研究了原胞结构的改变对负折射行为的影响.数值仿真结果表明，对原胞结构做微小调节也可获得负折射率频带的增大效应.将双鱼网结构改为阶梯形孔洞和半球形孔洞结构，可以在更多的频段里出现负折射率，并且谐振频率发生了一定的红移.半球形孔洞的双鱼网结构可以方便地用化学模板法制备，这为从实验上实现红外及可见光波段的多频负折射材料提供了一种简单可行的方法. 关键词： 负折射率 多频段 双鱼网结构

Multiband negative index metamaterials at optical frequencies

Based on the fishnet negative index metamaterials （NIMs） of circular-shaped holes operating at optical frequencies，the influence of modifying the hole shape is studied using the commercial software package CST Microwave studio. Numerical simulations show that，even a tiny modification may lead to broadening of the negative refractive band. So we designed two fishnet NIMs of the gradient holes and half-global holes. Compared with the fishnet NIMs of circular-shaped holes，these two structures can realize negative refraction at multi-frequency bands，and the resonance frequencies exhibit an obvious red-shift. We present a chemical technique for preparing the fishnet NIMs of half-global holes，which is a simple and feasible way to realize multiband negative index metamaterials at optical frequencies.