论文标题
光学强耦合金属内部的纳米级工程
Nanoscale engineering of optical strong coupling inside metals
论文作者
论文摘要
当物质激发与光学模式强烈伴侣时，光学极性会出现。分子过渡和光腔之间的这种强耦合在修改化学物质的基本特性方面带来了深远的机会。最近，由于其几何形状维持光学模式的物质，已经出现了无腔极化的令人兴奋的前景。在这里，我们展示了在纳米级的镍中如何设计带的频带过渡和表面等离子体的强耦合，以实现金属内无腔光学极性子。使用电子损失光谱法，我们证明在薄膜和纳米antennas中，传播和辐射损失导致等离子线宽扩大，并且从强耦合到弱耦合。此外，高阶等离子体共振夫妇与带间跃迁，而多极耦合状态获得了等离子体的场曲线。我们的结果提供了对金属中等离子体间隔耦合的基本理解，并为设计不可预见的光催化和磁光纳米系统的设计建立了基础。
Optical polaritons appear when a material excitation strongly couples to the optical mode. Such strong coupling between molecular transitions and optical cavities results in far-reaching opportunities in modifying fundamental properties of chemical matter. More recently an exciting prospect of cavity-free polaritons has emerged by matter sustaining the optical mode with its geometry. Here we show how strong coupling of the interband transition and surface plasmons can be engineered in nickel at the nanoscale to realize cavity-free optical polaritons inside metals. Using electron energy-loss spectroscopy, we demonstrate that in thin films and nanoantennas the propagation and radiation losses result in a broadening of the plasmon linewidth and a transition from strong to weak coupling. Further, higher-order plasmon resonances couple to the interband transition, and the multipolar coupled states acquire the field profile of the plasmon. Our results provide a fundamental understanding of plasmon-interband coupling in metals and establish the base for the design of unforeseen photocatalytic and magneto-optical nanosystems.
