Zand Iman, Mahigir Amirreza, Pakizeh Tavakol, Abrishamian Mohammad S
Faculty of Electrical and Computer Engineering, K. N. Toosi University of Technology, Tehran 16314, Iran.
Opt Express. 2012 Mar 26;20(7):7516-25. doi: 10.1364/OE.20.007516.
A nanoplasmonic optical filtering technique based on a complementary split-ring resonator structure is proposed. The basic and modal properties of the square-nanoring are studied using the group theory. Degeneracy and non-degeneracy of the possible TM odd- and even-modes are characterized based on the symmetry elements of the ring structure. Distinctively, the proposed technique allows selecting and exciting the proper plasmonic modes of the nanoring in the side-coupled arrangement. It is found that the non-integer modes can be excited due to the presence of a metallic nano-wall. These modes are highly sensitive to the nano-wall dimensions, in contrast to the regular integer modes. Moreover, the transmission-line theory is used to derive the resonance condition of the modes. The results show the optical transmission spectrum of the investigated filter can be efficiently modified and tuned either by manipulation of the position or by variation of the width of the employed nano-wall inside the ring. The numerical results support the theoretical analysis.
提出了一种基于互补开口环谐振器结构的纳米等离子体光学滤波技术。利用群论研究了方形纳米环的基本性质和模态特性。基于环形结构的对称元素，对可能的TM奇模和偶模的简并性和非简并性进行了表征。独特的是，所提出的技术允许在侧耦合排列中选择和激发纳米环的适当等离子体模式。发现由于金属纳米壁的存在，可以激发非整数模式。与规则的整数模式相比，这些模式对纳米壁尺寸高度敏感。此外，利用传输线理论推导了模式的共振条件。结果表明，通过操纵纳米壁在环内的位置或改变其宽度，可以有效地修改和调谐所研究滤波器的光学传输光谱。数值结果支持理论分析。
