Artificial Uniaxial And Biaxial Dielectrics With Use Of 2-Dimensional Subwavelength Binary Gratings

    Authors

    E. B. Grann; M. G. Moharam;D. A. Pommet

    Comments

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    Abbreviated Journal Title

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

    Keywords

    DIFFRACTIVE OPTICS; ARTIFICIAL MEDIUM; ANTIREFLECTION; BINARY GRATINGS; ANTIREFLECTION-STRUCTURED SURFACES; RELIEF GRATINGS; OPTICS; Optics

    Abstract

    Two-dimensional symmetric and asymmetric subwavelength binary gratings are investigated. A method for determining the three effective indices of a two-dimensional (2-D) subwavelength grating is presented, as well as a theoretical formalization for the effective index parallel with the normal to the surface. It is shown that a 2-D asymmetric binary grating on the surface of a dielectric substrate is analogous to a biaxial thin film. If the grating is symmetric, then the two effective indices perpendicular to the normal are equal, and the grating is analogous to a uniaxial thin film. Using these effective indices and the quarter-wave Tschebyscheff synthesis technique, we designed two- and three-level binary gratings to suppress reflections over a broad band. It is shown that for a substrate index of n(s) = 3.0 a three-level 2-D binary grating reduced reflections below 0.1% from 8 mu m to 12 mu m.

    Journal Title

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

    Volume

    11

    Issue/Number

    10

    Publication Date

    1-1-1994

    Document Type

    Article

    Language

    English

    First Page

    2695

    Last Page

    2703

    WOS Identifier

    WOS:A1994PH98600015

    ISSN

    0740-3232

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