____________Scanning Optical Microscopy (NSOM)___________

 

Near-field scanning optical microscope, NSOM is a type of optical microscope that  allows imaging the surface of solid samples with a spatial resolution beyond the diffraction limit. It uses a sharpened optical fiber (average aperture diameter 100 nm), which illuminates the surface being positioned at the very small distance from the surface (in the near-field), scanning the sample line by line.
The light reflected or passing through the sample is then collected by a microscope objective in far-field and delivered to the detector. The microscope can be connected to a fluorescence spectrometer through a set of optical fibers, which allows recording the spectrum from the selected point on the surface. The microscope also works in the AFM mode, providing information on the topography of the sample surface.