Scanning near-field optical microscopy (SNOM) is an optical microscopy
whose resolution is not bound to the diffraction limit. It provides c
hemical information based upon spectral, polarization and/or fluoresce
nce contrast images. Details as small as 20 nm can be recognized. Phot
ophysical and photochemical effects can be studied with SNOM on a simi
lar scale. This article reviews a good deal of the experimental and th
eoretical work on SNOM in Switzerland.