Leakage radiation microscopy has been used to examine chemical interface damping (CID) for the propagating surface plasmon polariton (PSPP) modes of Au nanostripes-nanofabricated structures with heights of 40 or 50 nm, widths between 2 and 4 µm, and 100 µm lengths. Real space imaging was used to determine the propagation lengths LSPP of the leaky PSPP modes, and back focal plane measurements generated ω vs k dispersion curves, which yield the PSPP group velocities vg. The combination of these two experiments was used to calculate the PSPP lifetime via T1 = LSPP/vg. The difference in T1 times between bare and thiol coated nanostripes was used to determine the dephasing rate due to CID ΓCID for the adsorbed thiol molecules. A variety of different thiol molecules were examined, as well as nanostripes with different dimensions. The values of ΓCID are similar for the different systems and are an order-of-magnitude smaller than the typical values observed for the localized surface plasmon resonances (LSPRs) of Au nanoparticles. Scaling the measured ΓCID values by the effective path length for electron-surface scattering shows that the CID effect for the PSPP modes of the nanostripes is similar to that for the LSPR modes of nanoparticles. This is somewhat surprising given that PSPPs and LSPRs have different properties: PSPPs have a well-defined momentum, whereas LSPRs do not. The magnitude of ΓCID for the nanostripes could be increased by reducing their dimensions, principally the height of the nanostructures. However, decreasing dimensions for the leaky PSPP mode increases radiation damping, which would make it challenging to accurately measure ΓCID.

中文翻译：

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化学界面阻尼，用于在金纳米带中传播表面等离激元极化子。

泄漏辐射显微镜已用于检查金纳米带-纳米结构的传播表面等离振子极化（PSPP）模式的化学界面阻尼（CID），该结构的高度为40或50 nm，宽度为2-4 µm，长度为100 µm。实际空间成像用于确定泄漏PSPP模式的传播长度LSPP，后焦平面测量生成ωvs k色散曲线，从而得出PSPP组速度vg。这两个实验的组合用于通过T1 = LSPP / vg计算PSPP寿命。裸露的和巯基涂覆的纳米带之间的T1时间差用于确定由于吸附的巯基分子的CIDΓCID而引起的移相速率。检查了各种不同的硫醇分子以及尺寸不同的纳米带。对于不同的系统，ΓCID的值相似，并且比在Au纳米粒子的局部表面等离振子共振（LSPR）上观察到的典型值小一个数量级。通过对电子表面散射的有效路径长度来缩放测得的ΓCID值，表明纳米带的PSPP模式的CID效应与纳米粒子的LSPR模式的CID效应相似。鉴于PSPP和LSPR具有不同的属性，这有点令人惊讶：PSPP具有明确的动量，而LSPR没有。可以通过减小纳米带的尺寸（主要是纳米结构的高度）来增加ΓCID的大小。但是，减小泄漏PSPP模式的尺寸会增加辐射衰减，这将给准确测量ΓCID带来挑战。