Kazuo TANAKA^*, Mengyun YAN and Masahiro TANAKA

Department of Electronics and Computer Engineering of Gifu University, Yanagido 1-1, Gifu 510-1193, Japan

(Received November 22, 2001; Accepted May 27, 2002)

We investigated near-field optical (NFO) imaging characteristics of a small object placed on a dielectric slab by a computer-code using a three-dimensional volume integral equation with an effective iteration technique called the generalized minimal residual method. A simplified three-dimensional NFO microscope that consists of a small dielectric object placed on the dielectric substrate and a small dielectric sphere as a scanning probe-tip was considered. Calculating two-dimensional output images obtained from scattered far fields, we studied the effect of the substrate on NFO output images, the comparison of NFO output images with electrostatic field around the small object, the dependence of output image characteristics on the wavelength and the difference of imaging characteristics between incident plane waves and incident evanescent waves.

Key words: near-field optics, integral equation, numerical simulation, microscopic image