Resolution in near-field optical microscopy

A discussion of the relationship between the spatial resolution in near-field and far-field microscopy is presented in the context of linear optical transfer function theory. The results of a simplified theory of near-field optical beam formation are compared with experimental measurements of the near-field probe profile using visible light and subwavelength probes. The radial intensity profile of a near-field light beam is shown to be describable to a first approximation by a simple Gaussian function.