Lee Sangjun, Kim Sangin
School of Electrical and Computer Engineering, Ajou University, Suwon 443-749, Korea.
Opt Express. 2010 Feb 1;18(3):2197-208. doi: 10.1364/OE.18.002197.
We propose a novel waveguide structure using a hetero-metal film which is composed of two metals of different plasma frequencies. In the proposed waveguide, a long-range surface plasmon-polariton (LR-SPP) mode in the central metal film of a higher plasma frequency are horizontally confined since no propagation mode is allowed in the outer films of a lower plasma frequency for a certain frequency range which is dubbed a plasmonic mode-gap (PMG). The propagation characteristics of the proposed PMG waveguide are numerically analyzed. The proposed waveguide shows tight horizontal confinement close to the diffraction limit and notable suppression of radiation loss in bendings due to the PMG effect. It seems that the PMG guiding can improve integration densities of optical devices based on the LR-SPPs without exacerbating their propagation losses.
我们提出了一种新型的波导结构，该结构使用了由两种具有不同等离子体频率的金属组成的异质金属膜。在所提出的波导中，由于在较低等离子体频率的外层膜中对于被称为等离子体模式间隙（PMG）的特定频率范围不允许传播模式，因此在较高等离子体频率的中心金属膜中的长程表面等离激元极化激元（LR-SPP）模式在水平方向上受到限制。对所提出的PMG波导的传播特性进行了数值分析。所提出的波导由于PMG效应，在接近衍射极限处表现出紧密的水平限制，并且在弯曲处显著抑制了辐射损耗。似乎PMG波导可以提高基于LR-SPP的光学器件的集成密度，而不会加剧其传播损耗。
