[OPTICAL REVIEW Vol. 4, No. 1B (1997) 228-231]

Optical near field scattered by surface defects: Two-dimensional numerical analysis*

Shu WANG and Mufei XIAO

Instituto de Física, Universidad Nacional Autónoma de México, Apartado Postal 2681, 22800 Ensenada, Baja California, México

(Received August 17, 1996; Accepted November 1, 1996)

Recently developed scanning near-field optical microscopy has drawn attention to the problem of describing the electromagnetic field in the close vicinity of a surface. In this work, we present a numerical simulation that solves rigorously the field equations for a dielectric-air-dielectric layer system with arbitrary one-dimensional structure at its interfaces. Our theory is applied to calculate the intensity of the near field transmitted at the center of the tip of a probe as it is moved at a constant height above a surface with two identical topographic defects. The effects on the optical image due to the separation of the objects, and the shape difference between the ridges and grooves are discussed. The resolution limit and the conditions for near field interaction are determined.

Key words : near field optics - microscopy - SNOM - PSTM - theoretical modeling

*This paper was originally presented at the first Asia-Pacific Workshop on Near Field Optics, which was held on August 17 and 18, 1996 at Seoul Education and Culture Center, Seoul, Korea, organized by Condensed Matter Research Institute, Seoul National University.