NEAR-FIELD OPTICS THEORIES

The development of near-field optics theory is reviewed. We first reca ll that near-field optics is not limited to near-field microscopy. Bro adly speaking, it concerns phenomena involving evanescent electromagne tic waves. The importance of such waves was ignored for a long time in optical and surface physics until the emergence of scanning near-fiel d optical microscopes. Taking evanescent waves into account prevents t he use of any simple approximation in the set of Maxwell's equations. The various theoretical approaches of near-field optics are discussed from the point of view of their ability to assess evanescent electroma gnetic waves. We discuss the main results of the application of the va rious practical schemes which all rely on a numerical procedure.