等离子体诱导的非局域二次谐波生成用于埋界面光谱学
Plasmon Induced Delocalized Second-Harmonic Generation Towards Buried-Interface Spectroscopy
AI总结：
研究通过等离子体极化子介导的非局域二次谐波生成，实现了对埋界面的高灵敏度探测，展示了单束激发下多层样品的广泛应用潜力。
摘要：
二次谐波生成显微镜是一种能够探测界面局部晶体对称性和电场的强大技术。然而，它常因信号弱而在多层系统中难以解释。本文直接观察到在金单晶表面和结构上，由表面等离子体极化子介导的非局域二次谐波生成。我们生成了距激发点35微米的二次谐波光，并且在没有基本激发光束的情况下，从原子平坦表面获得信号。我们揭示这一过程源于两个反向传播表面等离子体极化子的相互作用，这是微尺度上首次观察到这一过程。该信号具有与局域二次谐波生成相同的偏振依赖性，并以垂直于样品表面的准直光束发射。部分由于局部电场增强，我们能够使用CMOS相机在1秒曝光和无增益的情况下观察到这些信号。我们的结果使单束激发下广泛探测多层样品成为可能，应用包括能源、催化和单粒子表面传感。
英文摘要：
Second-harmonic generation microscopy is a powerful technique capable of probing local crystal symmetries and electric fields at interfaces. However, it often suffers from weak signal strength and is difficult to understand in multilayer systems where many materials can give competing signal contributions. In this work we present direct observation of delocalized, surface plasmon polariton-mediated second-harmonic generation on gold monocrystalline surfaces and structures. We generate second-harmonic light up to 35 um from the excitation spot and, excitingly, we obtain signal from atomically flat surfaces without a fundamental excitation beam present in the same region. We reveal that this process arises from the interaction of two counter-propagating surface plasmon polaritons, which we believe to be the first observation of this process at the microscale. This signal has the same polarisation dependence as localised second-harmonic generation and is emitted in a collimated beam travelling perpendicular to the sample surface. In part due to local electric field enhancements, we were able to observe these signals on a CMOS camera with 1 s exposure and no gain using an industrial-grade pulsed laser. Our results enable wide area multilayer samples to be probed using a single excitation beam, with applications including in energy, catalysis and single particle surface sensing.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
