Abstract

Diffraction from wavelength-size surface-relief structures has considerable physical importance and many practical applications. One relevant treatment of this problem has shown that the apparent sizes of the obstacles are different from their real geometrical sizes.¹ In this paper we will present a further experimental and numerical analysis of diffraction of electromagnetic waves from near-wavelength-size and subwavelength-size surface-relief slots. The fabrication procedure, which involves plotting photographic masks and contact printing them onto a photoresist, will be outlined. By rigorously evaluating the complex value of the surface current nearby, the amplitude and the shape of the wave front can be obtained. The far-field intensity is obtained by taking into account the output wave front just above the surface. The results to be explained include the effects of incident angle, slot width and depth, finite conductivity and complex permittivity of the material, and the polarization states. The experimental results for various cases will be compared with one another and with numerical results.

© 1990 Optical Society of America