MACROSCOPIC SELF-CONSISTENT MODEL FOR EXTERNAL-REFLECTION NEAR-FIELD MICROSCOPY

The self-consistent macroscopic approach based on the Maxwell equation s in two-dimensional geometry is developed to describe tip-surface int eraction in external-reflection near-field microscopy. The problem is reduced to a single one-dimensional integral equation in terms of the Fourier components of the field at the plane of the sample surface. Th is equation is extended to take into account a pointlike scatterer pla ced on the sample surface. The power of light propagating toward the d etector as the fiber mode is expressed by using the self-consistent fi eld at the tip surface. Numerical results for trapezium-shaped tips ar e presented. We show that the sharper tip and the more confined fiber mode result in better resolution of the near-field microscope. Moreove r, it is found that the tip-surface distance should not be too small s o that better resolution is ensured.