Wetter Helene, Fedorova Zlata, Linden Stefan
Opt Lett. 2022 Jun 15;47(12):3091-3094. doi: 10.1364/OL.458954.
Evanescently coupled waveguides are a powerful platform to study and visualize the wave dynamics in tight-binding systems. Here, we investigate the propagation of surface plasmon polaritons in arrays of dielectric loaded surface plasmon polariton waveguides with a propagation constant gradient acting as an effective external potential. Using leakage radiation microscopy, we observe in real-space for single site excitation a periodic breathing of the wave packet and an oscillatory motion in the case of Gaussian excitation of multiple waveguides. The corresponding momentum-resolved spectra are composed of sets of equally spaced modes. We interpret these observations as the plasmonic analogs of Bloch oscillations and the Wannier-Stark ladder, respectively.
倏逝耦合波导是研究和可视化紧束缚系统中波动动力学的强大平台。在此，我们研究了表面等离激元极化激元在介质加载表面等离激元极化激元波导阵列中的传播，其中传播常数梯度作为有效的外部势。利用泄漏辐射显微镜，我们在实空间中观察到，对于单位点激发，波包呈现周期性呼吸，而在多个波导的高斯激发情况下，波包呈现振荡运动。相应的动量分辨光谱由等间距模式集组成。我们分别将这些观测结果解释为布洛赫振荡和万尼尔-斯塔克阶梯的等离激元类似物。
