Coherent perfect absorption (CPA) describes the absence of all outgoing modes from a lossy resonator, driven by lossless incoming modes. Here, we show that for nanoresonators that also exhibit radiative losses, e.g., plasmonic nanoantennas, a generalized version of CPA (gCPA) can be applied. In gCPA outgoing modes are suppressed only for a subset of (guided plasmonic) modes while other (radiative) modes are treated as additional loss channels - a situation typically referred to as perfect impedance matching. Here we make use of gCPA to show how to achieve perfect impedance matching between a single nanowire plasmonic waveguide and a plasmonic nanoantenna. Antennas with both radiant and subradiant characteristics are considered. We further demonstrate potential applications in background-free sensing.

中文翻译：

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使用广义相干完美吸收以完美阻抗匹配驱动等离子体纳米天线

相干完美吸收 (CPA) 描述了由无损传入模式驱动的有损谐振器的所有传出模式的缺失。在这里，我们展示了对于也表​​现出辐射损耗的纳米谐振器，例如等离子体纳米天线，可以应用 CPA (gCPA) 的广义版本。在 gCPA 中，输出模式仅针对（引导等离子体）模式的一个子集被抑制，而其他（辐射）模式被视为额外的损耗通道 - 这种情况通常称为完美阻抗匹配。在这里，我们利用 gCPA 来展示如何在单个纳米线等离子体波导和等离子体纳米天线之间实现完美的阻抗匹配。考虑了具有辐射和亚辐射特性的天线。我们进一步展示了在无背景传感中的潜在应用。