1. Principle of the near-field microscope

To appreciate the originality of these new instruments, and to pinpoint the origin of their excellent resolving power, we need to return briefly to the operating principle of a traditional microscope.

In traditional microscopes (optical or electronic), a source of waves (or corpuscles) illuminates an object. The diffracted radiation is then conveyed through optics to the detector (CCD...), which gives an enlarged image of the object. The source-sample and sample-detector distances are much greater than the wavelength λ of the radiation used.

The smallest distance that can be perceived in the image plane (inverse of the lateral resolving power) is of the order of λ; this theoretical limit is inherent to the phenomenon of radiation propagation through magnification optical systems and in particular to the phenomenon of diffraction....