Diamond colour centres as a nanoscopic light source for scanning near-field optical microscopy

Recently it was shown that a single molecule at cryogenic temperatures could be used as a local light source for illumination of a sample in the near field. Conventional light-emitting systems such as dye molecules and semiconductor quantum dots could also be used for this purpose, but they suffer from lack of photostability. However, colour centres in diamond have been found to be remarkably stable against bleaching and blinking effects. Here we present the first SNOM images taken with nanoscopic diamond crystals as a light source.