THEORY FOR THE APERTURELESS NEAR-FIELD OPTICAL MICROSCOPE - IMAGE-RESOLUTION

A theory for the apertureless scanning near-field optical microscope (SNOM) in the case of weak fluctuations of either the refractive index or of the object surface corrugation was reported. It was demonstrated that the measured phase delay was dependent quadratically on the fluctuation. The ultimate resolution should be around 7 nm for the optimum estimate fluctuations. To achieve the 3 nm resolution reported in the Zenhausern, O'Boyle, and Wickramasinghe paper, the phase fluctuation should be approx.30% or greater. Interferometric measurements should comprise significant advance in SNOM.