New development of nanoscale spectroscopy using scanning probe microscope Available to Purchase

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.