论文标题
激动
Exciting space-time surface plasmon polaritons by irradiating a nanoslit structure
论文作者
论文摘要
时空（ST）波数据包是传播不变的脉冲光束，可在无衍射或分散体的可调组速度下以介电自由传播。因为即使仅考虑一个横向尺寸，ST波数据包也能保持这些特征，因此它们可以实现具有与自由传播的同类产品相同独特特征的金属二二电界面的表面等离子体（例如，我们称为ST-SPPS的表面等离子体极化）。但是，由于ST-SPPS的时空光谱结构是它们对金属表面的繁殖的关键，因此必须仔细考虑其激发方法。我们在这里使用有限差分时间域（FDTD）模拟表明，在自由空间中适当合成的ST波数据包可以通过金属表面上的单个纳米尺度缝隙与ST-SPP夫妇伴侣。我们的计算证实，这种激发方法会产生在各个维度（因此可以被视为等离子体的“子弹”）中进行表面结合的ST-SPP，它们在没有衍射或可调组速度的无衍射或分散体的金属二射线界面上僵硬地传播。
Space-time (ST) wave packets are propagation-invariant pulsed optical beams that travel freely in dielectrics at a tunable group velocity without diffraction or dispersion. Because ST wave packets maintain these characteristics even when only one transverse dimension is considered, they can realize surface-bound waves (e.g., surface plasmon polaritons at a metal-dielectric interface, which we call ST-SPPs) that have the same unique characteristics of their freely propagating counterparts. However, because the spatio-temporal spectral structure of ST-SPPs is key to their propagation invariance on the metal surface, their excitation methodology must be considered carefully. We show here using finite-difference time-domain (FDTD) simulations that an appropriately synthesized ST wave packet in free space can be couples to a ST-SPP via a single nano-scale slit inscribed in the metal surface. Our calculations confirm that this excitation methodology yields surface-bound ST-SPPs that are locarized in all dimensions (and can thus be considered as plasmonic 'bullets'), which travel rigidly at the metal-dielectric interface without diffraction or dispersion at a tunable group velocity.
