Scanning Near-Field Optical Microscopy for Investigations of Bio-Matter

Optical near-fields can be employed for a wide range of applications, e.g., light localization, light scattering, and field enhancement. In this chapter the principles of near-field scanning optical microscopy (NSOM) will be outlined. The basic idea of this technique is the extension of the bandwidth of accessible spatial frequencies beyond the limits of conventional light microscopy. This strategy has been implemented in different ways. By now this technique covers a broad spectrum of optical contrasts. Here, special attention is turned on the high-resolution spectroscopic imaging of biological samples.