Possibilities of functionalized probes in optical near-field microscopy

Functionalization, bringing new functions to standard approaches, is used in different fields of science. Functionalized probes have found wide application in atomic force microscopy, especially in force spectroscopy and for the specific recognition of single molecules. At the same time they have found only minor application in scanning near-field optical microscopy in spite of the possibility to obtain new information. This article considers examples of the use of functionalized tips in near-field optics and emphasizes the new approach based on tip-enhanced Raman scattering (TERS) with functionalized tips. The concept of Raman probe is described considering some possible perspectives as well as the demonstration of an internal standard in TERS based on a functionalized tip.