Institute of Microelectronics, Tsinghua University , Beijing 100084, China.
Department of Electrical Engineering, Stanford University , Stanford, California 94305, United States.
ACS Nano. 2016 Jul 26;10(7):6716-24. doi: 10.1021/acsnano.6b02031. Epub 2016 Jun 28.
Plasmonic antennas are building blocks in advanced nano-optical systems due to their ability to tailor optical response based on their geometry. We propose an electrochemical approach to program the optical properties of dipole antennas in a scalable, fast, and energy-efficient manner. These antennas comprise two arms, one serving as an anode and the other a cathode, separated by a solid electrolyte. As a voltage is applied between the antenna arms, a conductive filament either grows or dissolves within the electrolyte, modifying the antenna load. We probe the dynamics of stochastic filament formation and their effects on plasmonic mode programming using a combination of three-dimensional optical and electronic simulations. In particular, we identify device operation regimes in which the charge-transfer plasmon mode can be programmed to be "on" or "off." We also identify, unexpectedly, a strong correlation between DC filament resistance and charge-transfer plasmon mode frequency that is insensitive to the detailed filament morphology. We envision that the scalability of our electrochemical platform can generalize to large-area reconfigurable metamaterials and metasurfaces for on-chip and free-space applications.
等离子体激元天线由于能够根据其几何形状调整光学响应，因此是先进的纳米光学系统的基本组成部分。我们提出了一种电化学方法，能够以可扩展、快速和节能的方式对偶极子天线的光学性质进行编程。这些天线由两个臂组成，一个臂作为阳极，另一个臂作为阴极，它们由固体电解质隔开。当在天线臂之间施加电压时，电解质中要么会生长出一个导电丝，要么会溶解一个导电丝，从而改变天线的负载。我们使用三维光学和电子模拟相结合的方法来探测随机丝形成的动力学及其对等离子体模式编程的影响。特别是，我们确定了可以将电荷转移等离子体模式编程为“开”或“关”的器件工作模式。我们还出人意料地发现，直流丝电阻和电荷转移等离子体模式频率之间存在很强的相关性，而这种相关性对丝的形态细节不敏感。我们设想，我们的电化学平台的可扩展性可以推广到大面积可重构超材料和超表面，以用于片上和自由空间应用。
