Compact Magnetic Antennas for Directional Excitation of Surface Plasmons
Compact Magnetic Antennas for Directional Excitation of Surface Plasmons
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DOI：
10.1021/nl302339z
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发表时间：
2012-09-01
期刊：
影响因子：
10.8
通讯作者：
Zhang, Xiang
中科院分区：
文献类型：
--
作者：
Liu, Yongmin;Palomba, Stefano;Zhang, Xiang
等离子体激元被认为是实现下一代超快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来将单个等离子体激元组分按比例缩小到纳米范围。然而，一个紧凑的等离子体激元源，可以有效地产生表面等离子体激元（SPP），并提供SPP感兴趣的区域尚未实现。在这里，桥接光学天线理论和最近开发的超材料的概念，我们展示了一个亚波长，高效的等离子体源定向产生的表面等离子体。所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。在工作波长处，入射光子可以被有效地引导到由电场偏振调制的SPP波中。通过调整谐振时的相对相位和两个纳米谐振器之间的间隔，可以控制SPP主要沿着沿着一个特定方向传播。这种新型的磁性纳米天线为近场操纵光子提供了一种新的方法，也可以用于基于SPP的非线性应用，有源调制和无线光通信。
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.