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On the convergence of the coupled-wave approach for lamellar diffraction gratingsAmong the many existing rigorous methods for analyzing diffraction of electromagnetic waves by diffraction gratings, the coupled-wave approach stands out because of its versatility and simplicity. It can be applied to volume gratings and surface relief gratings, and its numerical implementation is much simpler than others. In addition, its predictions were experimentally validated in several cases. These facts explain the popularity of the coupled-wave approach among many optical engineers in the field of diffractive optics. However, a comprehensive analysis of the convergence of the model predictions has never been presented, although several authors have recently reported convergence difficulties with the model when it is used for metallic gratings in TM polarization. Herein, three points are made: (1) in the TM case, the coupled-wave approach converges much slower than the modal approach of Botten et al; (2) the slow convergence is caused by the use of Fourier expansions for the permittivity and the fields in the grating region; and (3) is manifested by the slow convergence of the eigenvalues and the associated modal fields. The reader is assumed to be familiar with the mathematical formulations of the coupled-wave approach and the modal approach.
Document ID
19930006331
Acquisition Source
Legacy CDMS
Document Type
Other
Authors
Li, Lifeng (Arizona Univ. Tucson, AZ, United States)
Haggans, Charles W. (Arizona Univ. Tucson, AZ, United States)
Date Acquired
September 6, 2013
Publication Date
March 15, 1992
Publication Information
Publication: Research Studies on Advanced Optical Module(Head Designs for Optical Data Storage
Subject Category
Optics
Accession Number
93N15520
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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