Near-field optics theories

TLDR

Near‑field optics theory, which deals with evanescent electromagnetic waves beyond microscopy, has evolved from long‑ignored surface physics to a field requiring full Maxwell solutions, especially after the advent of scanning near‑field optical microscopes. The study surveys theoretical approaches to near‑field optics, evaluating their capacity to model evanescent electromagnetic waves. The authors analyze different theoretical frameworks, judging each by how well it can model evanescent electromagnetic waves. The application of practical schemes, all based on numerical procedures, yields key results that illustrate their effectiveness.

Abstract

The development of near-field optics theory is reviewed. We first recall that near-field optics is not limited to near-field microscopy. Broadly speaking, it concerns phenomena involving evanescent electromagnetic waves. The importance of such waves was ignored for a long time in optical and surface physics until the emergence of scanning near-field optical microscopes. Taking evanescent waves into account prevents the 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 electromagnetic waves. We discuss the main results of the application of the various practical schemes which all rely on a numerical procedure.