Song Jung-Hwan, Raza Søren, van de Groep Jorik, Kang Ju-Hyung, Li Qitong, Kik Pieter G, Brongersma Mark L
Geballe Laboratory for Advanced Materials, Stanford University, Stanford, CA, 94305, USA.
Department of Physics, Technical University of Denmark, DK-2800, Kongens Lyngby, Denmark.
Nat Commun. 2021 Jan 4;12(1):48. doi: 10.1038/s41467-020-20273-2.
The ability of two nearly-touching plasmonic nanoparticles to squeeze light into a nanometer gap has provided a myriad of fundamental insights into light-matter interaction. In this work, we construct a nanoelectromechanical system (NEMS) that capitalizes on the unique, singular behavior that arises at sub-nanometer particle-spacings to create an electro-optical modulator. Using in situ electron energy loss spectroscopy in a transmission electron microscope, we map the spectral and spatial changes in the plasmonic modes as they hybridize and evolve from a weak to a strong coupling regime. In the strongly-coupled regime, we observe a very large mechanical tunability (~250 meV/nm) of the bonding-dipole plasmon resonance of the dimer at ~1 nm gap spacing, right before detrimental quantum effects set in. We leverage our findings to realize a prototype NEMS light-intensity modulator operating at ~10 MHz and with a power consumption of only 4 fJ/bit.
两个几乎接触的等离子体纳米颗粒将光挤压到纳米间隙中的能力，为光与物质相互作用提供了众多基本见解。在这项工作中，我们构建了一个纳米机电系统（NEMS），该系统利用在亚纳米粒子间距下出现的独特、奇异行为来创建一个电光调制器。通过在透射电子显微镜中使用原位电子能量损失谱，我们绘制了等离子体模式在从弱耦合到强耦合状态杂交和演化时的光谱和空间变化。在强耦合状态下，我们观察到在大约1纳米的间隙间距处，二聚体的键合偶极子等离子体共振具有非常大的机械可调性（约250毫电子伏特/纳米），就在有害量子效应出现之前。我们利用我们的发现实现了一个工作频率约为10兆赫兹、功耗仅为4飞焦/比特的NEMS光强度调制器原型。
