NSF Nanoscale Science and Engineering Center (NSEC), 3112 Etcheverry Hall, University of California, Berkeley, California 94720, United States.
Nano Lett. 2012 Sep 12;12(9):4853-8. doi: 10.1021/nl302339z. Epub 2012 Aug 2.
Plasmonics is considered as one of the most promising candidates for implementing the next generation of ultrafast and ultracompact photonic circuits. Considerable effort has been made to scale down individual plasmonic components into the nanometer regime. However, a compact plasmonic source that can efficiently generate surface plasmon polaritons (SPPs) and deliver SPPs to the region of interest is yet to be realized. Here, bridging the optical antenna theory and the recently developed concept of metamaterials, we demonstrate a subwavelength, highly efficient plasmonic source for directional generation of SPPs. The designed device consists of two nanomagnetic resonators with detuned resonant frequencies. At the operating wavelength, incident photons can be efficiently channeled into SPP waves modulated by the electric field polarization. By tailoring the relative phase at resonance and the separation between the two nanoresonators, SPPs can be steered to predominantly propagate along one specific direction. This novel magnetic nanoantenna paves a new way to manipulate photons in the near-field, and also could be useful for SPP-based nonlinear applications, active modulations, and wireless optical communications.
等离子体激元被认为是实现下一代超高速和超紧凑光子电路的最有前途的候选者之一。已经做出了相当大的努力将单个等离子体组件缩小到纳米级。然而，仍然需要实现一种能够有效地产生表面等离激元（SPP）并将 SPP 传输到感兴趣区域的紧凑型等离子体源。在这里，我们通过将光学天线理论和最近发展的超材料概念相结合，展示了一种亚波长、高效的等离子体源，用于定向产生 SPP。设计的器件由两个具有失谐谐振频率的纳米磁谐振器组成。在工作波长下，入射光子可以有效地被引导成由电场极化调制的 SPP 波。通过调整共振时的相对相位和两个纳米谐振器之间的分离，可以将 SPP 引导主要沿一个特定方向传播。这种新型磁性纳米天线为在近场中操纵光子开辟了一条新途径，并且对于基于 SPP 的非线性应用、主动调制和无线光通信也可能是有用的。
