Near-field optical random mapping (NORM) microscopy

Abstract: In recent years several methods to overcome diffraction limit in the far field microscopy have been demonstrated. Still the problem of superresolution is reliably solved only for fluorescent microscopy, giving a resolution of up to 20-30nm. Obtaining the optical resolution lower than 100nm without fluorescent dyes requires using rather slow and complicated technique of scanning near filed optical microscope (SNOM). We propose and demonstrate a method of optical near field acquisition by far-field microscope through observation of nanoparticles Brownian motion in immersion liquid. The resolution of the method is restricted only by the size of nanoparticles that can be registered (detected) by a given far field microscope. From this point of view this resolution can achieve up to 10-20nm. Up to now we achieved a resolution of about 140nm observing 120nm particles through an objective with N.A.=0.4. The resolution is thus improved by factor of five for a given microscope objective.