Komatsu Kazma, Pápa Zsuzsanna, Jauk Thomas, Bernecker Felix, Tóth Lázár, Lackner Florian, Ernst Wolfgang E, Ditlbacher Harald, Krenn Joachim R, Ossiander Marcus, Dombi Péter, Schultze Martin
Institute of Experimental Physics, Graz University of Technology, 8010 Graz, Austria.
Wigner Research Centre for Physics, 1121 Budapest, Hungary.
Nano Lett. 2024 Feb 28;24(8):2637-2642. doi: 10.1021/acs.nanolett.3c04991. Epub 2024 Feb 12.
Surface plasmon polaritons (SPPs) can confine and guide light in nanometer volumes and are ideal tools for achieving electric field enhancement and the construction of nanophotonic circuitry. The realization of the highest field strengths and fastest switching requires confinement also in the temporal domain. Here, we demonstrate a tapered plasmonic waveguide with an optimized grating structure that supports few-cycle surface plasmon polaritons with >70 THz bandwidth while achieving >50% light-field-to-plasmon coupling efficiency. This enables us to observe the─to our knowledge─shortest reported SPP wavepackets. Using time-resolved photoelectron microscopy with suboptical-wavelength spatial and sub-10 fs temporal resolution, we provide full spatiotemporal imaging of co- and counter-propagating few-cycle SPP wavepackets along tapered plasmonic waveguides. By comparing their propagation, we track the evolution of the laser-plasmon phase, which can be controlled via the coupling conditions.
表面等离激元极化激元（SPPs）能够在纳米尺度的空间内限制并引导光传播，是实现电场增强和构建纳米光子电路的理想工具。要实现最高场强和最快开关速度，还需要在时间域内进行限制。在此，我们展示了一种具有优化光栅结构的锥形等离子体波导，它能够支持带宽大于70太赫兹的少周期表面等离激元极化激元，同时实现大于50%的光场到等离子体的耦合效率。这使我们能够观察到——据我们所知——已报道的最短的SPP波包。利用具有亚光学波长空间分辨率和亚10飞秒时间分辨率的时间分辨光电子显微镜，我们对沿锥形等离子体波导同向和反向传播的少周期SPP波包进行了完整的时空成像。通过比较它们的传播情况，我们追踪了激光 - 等离子体相位的演变，该相位可通过耦合条件进行控制。
