Using the localized surface plasmon resonance (LSPR) of gold nanoparticles for sensing applications has attracted considerable interest, since it can be very sensitive, even down to a single molecule, and selective for a specific analyte molecule with a suitable surface modification. LSPR sensing is usually based on the wavelength shift of the LSPR or a Fano resonance. Here, we present a new experimental approach based on the phase of the light scattered by a single gold nanoparticle by equipping a confocal microscope with an additional interferometer arm similar to a Michelson interferometer. The detected phase depends on the shape of the nanoparticle and the refractive index of the surrounding medium and can even be detected for off-resonant excitation. This can be used as a new and sensitive detection method in LSPR sensing, allowing the detection of changes to the local refractive index or the binding of molecules to the nanoparticle surface.

中文翻译：

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纳米等离激元相位传感器。

使用金纳米颗粒的局部表面等离子体共振（LSPR）进行传感应用引起了极大的兴趣，因为它可以非常敏感，甚至可以低至单个分子，并且可以对具有适当表面修饰的特定分析物分子进行选择性选择。LSPR感测通常基于LSPR的波长偏移或Fano共振。在这里，我们通过为共焦显微镜配备类似于迈克尔逊干涉仪的附加干涉仪臂，提供了一种基于单个金纳米粒子散射光的相位的新实验方法。所检测到的相位取决于纳米粒子的形状和周围介质的折射率，甚至可以针对非共振激发进行检测。这可以用作LSPR感应中的一种新的敏感检测方法，