Optical tunneling microscopy of biostructures: a tool for non destructive high-resolution imaging

The purpose of this brief review communication is to show how the theory has been put to practical use for near-field (NF) optical interactions and to address the new opportunities for biomedical engineers in this field. This work covers only some restricted, but very interesting aspects, of NF applications, namely: optical frequencies and transmission mode by detection of the evanescent waves modulated by the presence of the specimen under investigation. The presence of an object on the total internal reflection (TIR) surface produces a modulation of the evanescent waveform, and this modulation causes spatial variations in the field intensity at a given height above the sample surface. These changes in intensity allow one to gather topographical information about the properties of the sample (i.e., spatial variations in the index of refraction)