Stable Implementation Of The Rigorous Coupled-Wave Analysis For Surface-Relief Gratings - Enhanced Transmittance Matrix Approach

    Authors

    M. G. Moharam; D. A. Pommet; E. B. Grann;T. K. Gaylord

    Comments

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    Abbreviated Journal Title

    J. Opt. Soc. Am. A-Opt. Image Sci. Vis.

    Keywords

    DIFFRACTION ANALYSIS; DIELECTRIC GRATINGS; SCATTERING; Optics

    Abstract

    An enhanced, numerically stable transmittance matrix approach is developed and is applied to the implementation of the rigorous coupled-wave analysis for surface-relief and multilevel gratings. The enhanced approach is shown to produce numerically stable results for excessively deep multilevel surface-relief dielectric gratings. The nature of the numerical instability for the classic transmission matrix approach in the presence of evanescent fields is determined. The finite precision of the numerical representation on digital computers results in insufficient accuracy in numerically representing the elements produced by inverting an ill-conditioned transmission matrix. These inaccuracies will result in numerical instability in the calculations for successive field matching between the layers. The new technique that we present anticipates and preempts these potential numerical problems. In addition to the full-solution approach whereby all the reflected and the transmitted amplitudes are calculated, a simpler, more efficient formulation is proposed for cases in which only the reflected amplitudes (or the transmitted amplitudes) are required. Incorporating this enhanced approach into the implementation of the rigorous coupled-wave analysis, we obtain numerically stable and convergent results for excessively deep (50 wavelengths), 16-level, asymmetric binary gratings. Calculated results are presented for both TE and TM polarization and for conical diffraction.

    Journal Title

    Journal of the Optical Society of America a-Optics Image Science and Vision

    Volume

    12

    Issue/Number

    5

    Publication Date

    1-1-1995

    Document Type

    Article; Proceedings Paper

    Language

    English

    First Page

    1077

    Last Page

    1086

    WOS Identifier

    WOS:A1995QV02900028

    ISSN

    0740-3232

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