Near-Field Optics: Microscopy, Spectroscopy, and Surface Modification Beyond the Diffraction Limit

TLDR

Near‑field optical microscopy employs a sharp probe to image, spectroscopically probe, or modify surfaces with ~12 nm resolution, preserving noninvasiveness, reliability, and low cost while extending most optical contrast mechanisms beyond the diffraction limit. The authors aim to apply this technique to localized optical spectroscopy of semiconductors and fluorescence imaging of living cells. The method successfully images nanometric features in mammalian tissues and creates ultrasmall magneto‑optic domains that could enable high‑density data storage.

Abstract

The near-field optical interaction between a sharp probe and a sample of interest can be exploited to image, spectroscopically probe, or modify surfaces at a resolution (down to approximately 12 nm) inaccessible by traditional far-field techniques. Many of the attractive features of conventional optics are retained, including noninvasiveness, reliability, and low cost. In addition, most optical contrast mechanisms can be extended to the near-field regime, resulting in a technique of considerable versatility. This versatility is demonstrated by several examples, such as the imaging of nanometric-scale features in mammalian tissue sections and the creation of ultrasmall, magneto-optic domains having implications for highdensity data storage. Although the technique may find uses in many diverse fields, two of the most exciting possibilities are localized optical spectroscopy of semiconductors and the fluorescence imaging of living cells.