Atomic-resolution Raman spectroscopy

Abstract

By combining scanning probe microscopy, laser spectroscopy, and surface science, researchers have sharpened the spatial resolution of microspectroscopy to the angstrom level. The study demonstrates a way to record vibrational spectra from select regions within a single molecule and a technique for capturing images of that molecule’s modes of vibration (Nature 2019, DOI: 10.1038/s41586-019-1059-9). Raman spectroscopy is a powerful tool for probing molecular vibrations. It’s used commercially for quality and process control and in research settings to study molecular phenomena. But the Raman signal, produced by sample molecules interacting with light—often visible light from lasers—is weak, limiting the method’s sensitivity. Over 40 years ago, researchers discovered that Raman signals could be boosted by a factor greater than 1 million by adsorbing analyte molecules on rough metal surfaces, such as silver, patterned with microscopically sharp points. The metal spikes acted like antennas, amplifying the elec...