Nanoscale spectroscopy and imaging, a hybrid technique that combines a scanning probe microscope (SPM) with spectroscopy, can provide nanoscale topographical, spectral, and chemical information of a sample. In recent years, developments in nanofabrication technology have dramatically advanced the field of nanospectroscopy for applications in various fields including nanoscale materials, electronics, catalysis, and biological systems. However, challenges in nanofocusing of light for excitation and extracting weak signals of individual molecules from the background signal persist in conventional nanoscale spectroscopy including tip-enhanced Raman spectroscopy, scanning near-field microscopy (SNOM/NSOM), and photoluminescence spectroscopy. This article reviews new approaches to design plasmonic SPM probes that improve important aspects of nanospectroscopy such as nanofocusing, far-to-near-field-coupling efficiency, background suppression, and ease of fabrication. The authors survey a diverse range of novel schemes to excite propagating surface plasmon polaritons on the probe surface to attain highly enhanced nanofocused light at the apex for nanoscale spectroscopies. These schemes include grating coupler configurations on the plasmonic SPM probes, aperture and apertureless plasmonic SNOM probes, nanostructured resonators coupled with a high-quality-factor photonic cavity, interfacing of the optical fiber with plasmonic nanowires, and nanoparticle-coupled plasmonic nanowires. These innovative probes merge the field of fiber optics, plasmonics, quantum optics, and nanomaterials. The authors provide a perspective on new approaches that combine the advantages of these probes and have the potential for significant advancement in nanoscale imaging and other types of nanoscale spectroscopies including scanning quantum spin spectroscopy and scanning thermal imaging microscopy.

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使用扫描探针显微镜的纳米光谱学的新发展

纳米级光谱学和成像是一种结合了扫描探针显微镜（SPM）和光谱学的混合技术，可以提供样品的纳米级形貌，光谱和化学信息。近年来，纳米制造技术的发展极大地推动了纳米光谱学领域的发展，可用于各种领域，包括纳米级材料，电子，催化和生物系统。但是，在传统的纳米级光谱学中，包括尖端增强拉曼光谱，扫描近场显微镜（SNOM / NSOM）和光致发光光谱学，激发和聚焦光从背景信号中提取单个分子的微弱信号仍然存在挑战。本文回顾了设计等离激元SPM探针的新方法，这些方法改善了纳米光谱学的重要方面，例如纳米聚焦，近场至近场耦合效率，背景抑制和易于制造。作者调查了各种新颖的方案，以激发探针表面上传播的表面等离激元极化子，以在纳米级光谱学的顶点处获得高度增强的纳米聚焦光。这些方案包括等离子SPM探针，孔径和无孔等离子SNOM探针上的光栅耦合器配置，与高品质因数光子腔耦合的纳米结构谐振器，光纤与等离子纳米线的接口以及与纳米粒子耦合的等离子纳米线。这些创新的探针融合了光纤，等离子体，量子光学和纳米材料的领域。