Kim Guhwan, Lee Myunghyun
Department of Electrical and Computer Engineering, Sungkyunkwan University, Suwon-si 16419, Korea.
Micromachines (Basel). 2021 Sep 30;12(10):1198. doi: 10.3390/mi12101198.
Work on controlling the propagation of surface plasmon polaritons (SPPs) through the use of external stimuli has attracted much attention due to the potential use of SPPs in nanoplasmonic integrated circuits. We report that the excitation of edge plasmon by TE-polarized light passing across gapped-SPP waveguides (G-SPPWs) leads to the suppressed transmission of long-range SPPs (LRSPPs) propagating along G-SPPWs. The induced current density by highly confined edge plasmon is numerically investigated to characterize the extended radiation length of decoupled LRSPPs by the TE-induced edge plasmon. The suppressed transmission of LRSPPs is confirmed using the measured extinction ratio of the plasmonic signals which are generated from the modulated optical signals, when compared to the extended radiation length calculated for a wide range of the input power. It is also shown that LRSPP transmission is sensitive to the excited power of edge plasmon in the gap through the permittivity change near the gap. Such a control of SPPs through the use of light could be boosted by the hybridized edge plasmon mode and a huge field enhancement using nanogap, gratings or metasurfaces, and could provide opportunities for ultrafast nano-plasmonic signal generation that is compatible with pervasive optical communication systems.
由于表面等离激元极化激元（SPPs）在纳米等离激元集成电路中的潜在应用，通过外部刺激来控制其传播的研究已引起广泛关注。我们报道，TE偏振光穿过间隙型表面等离激元极化激元波导（G-SPPWs）时激发的边缘等离激元，会导致沿G-SPPWs传播的长程表面等离激元极化激元（LRSPPs）的传输受到抑制。通过数值研究高度受限的边缘等离激元所感应的电流密度，以表征由TE诱导的边缘等离激元使解耦的LRSPPs的扩展辐射长度。与针对广泛输入功率计算出的扩展辐射长度相比，利用从调制光信号产生的等离激元信号的测量消光比，证实了LRSPPs的传输受到抑制。研究还表明，通过间隙附近介电常数的变化，LRSPP传输对间隙中边缘等离激元的激发功率敏感。利用光对表面等离激元极化激元的这种控制，可以通过混合边缘等离激元模式以及使用纳米间隙、光栅或超表面实现的巨大场增强来推动，并且可以为与普及的光通信系统兼容的超快纳米等离激元信号产生提供机会。
