Finite-difference time-domain modeling of nonperfectly conducting metallic thin-film gratings

Justin B. Judkins, Richard W. Ziolkowski

Research output: Contribution to journalArticle

128 Scopus citations

Abstract

A simulation tool based on the finite-difference time-domain (FDTD) technique is developed to model the electromagnetic interaction of a focused optical Gaussian beam in two dimensions incident on a simple model of a corrugated dielectric surface plated with a thin film of realistic metal. The technique is a hybrid approach that combines an intensive numerical method near the surface of the grating, which takes into account the optical properties of metals, with a free-space transform to obtain the radiated fields. A description of this technique is presented along with numerical examples comparing gratings made with realistic and perfect conductors. In particular, a demonstration is given of an obliquely incident beam focused on a uniform grating and a normally incident beam focused on a nonuniform grating. The gratings in these two cases are coated with a negative-permittivity thin film, and the scattered radiation patterns for these structures are studied. Both TE and TM polarizations are investigated. Using this hybrid FDTD technique results in a complete and accurate simulation of the total electromagnetic field in the near field as well as in the far field of the grating. It is shown that there are significant differences in the performances of the realistic metal and the perfect metal gratings.

Original languageEnglish (US)
Pages (from-to)1974-1983
Number of pages10
JournalJournal of the Optical Society of America A: Optics and Image Science, and Vision
Volume12
Issue number9
DOIs
StatePublished - Sep 1995

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Atomic and Molecular Physics, and Optics
  • Computer Vision and Pattern Recognition

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