Rigorous coupled-wave analysis of planar-grating diffraction
01 Jul 1981-Journal of the Optical Society of America (Optical Society of America)-Vol. 71, Iss: 7, pp 811-818
TL;DR: In this article, a rigorous coupled-wave approach is used to analyze diffraction by general planar gratings bounded by two different media, and the analysis is based on a state-variables representation and results in a unifying, easily computer-implementable matrix formulation.
Abstract: A rigorous coupled-wave approach is used to analyze diffraction by general planar gratings bounded by two different media. The grating fringes may have any orientation (slanted or unslanted) with respect to the grating surfaces. The analysis is based on a state-variables representation and results in a unifying, easily computer-implementable matrix formulation of the general planar-grating diffraction problem. Accurate diffraction characteristics are presented for the first time to the authors’ knowledge for general slanted gratings. This present rigorous formulation is compared with rigorous modal theory, approximate two-wave modal theory, approximate multiwave coupled-wave theory, and approximate two-wave coupled-wave theory. Typical errors in the diffraction characteristics introduced by these various approximate theories are evaluated for transmission, slanted, and reflection gratings. Inclusion of higher-order waves in a theory is important for obtaining accurate predictions when forward-diffracted orders are dominant (transmission-grating behavior). Conversely, when backward-diffracted orders dominate (reflection-grating behavior), second derivatives of the field amplitudes and boundary diffraction need to be included to produce accurate results.
Citations
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TL;DR: In this paper, the authors presented a stable and efficient numerical implementation of the analysis technique for one-dimensional binary gratings for both TE and TM polarization and for the general case of conical diffraction.
Abstract: The rigorous coupled-wave analysis technique for describing the diffraction of electromagnetic waves by periodic grating structures is reviewed. Formulations for a stable and efficient numerical implementation of the analysis technique are presented for one-dimensional binary gratings for both TE and TM polarization and for the general case of conical diffraction. It is shown that by exploitation of the symmetry of the diffraction problem a very efficient formulation, with up to an order-of-magnitude improvement in the numerical efficiency, is produced. The rigorous coupled-wave analysis is shown to be inherently stable. The sources of potential numerical problems associated with underflow and overflow, inherent in digital calculations, are presented. A formulation that anticipates and preempts these instability problems is presented. The calculated diffraction efficiencies for dielectric gratings are shown to converge to the correct value with an increasing number of space harmonics over a wide range of parameters, including very deep gratings. The effect of the number of harmonics on the convergence of the diffraction efficiencies is investigated. More field harmonics are shown to be required for the convergence of gratings with larger grating periods, deeper gratings, TM polarization, and conical diffraction.
2,437 citations
TL;DR: In this paper, 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.
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.
1,497 citations
TL;DR: The guided-mode resonance filter represents a basic new optical element with significant potential for practical applications and is presented and explained.
Abstract: The guided-mode resonance properties of planar dielectric waveguide gratings are presented and explained. It is shown that these structures function as filters that produce complete exchange of energy between forward- and backward-propagating diffracted waves with smooth line shapes and arbitrarily narrow filter linewidths. Simple expressions based on rigorous coupled-wave theory and on classical slab waveguide theory give a clear view and quantification of the inherent TE/TM polarization separation and the free spectral ranges of the filters. Furthermore, the resonance regimes, defining the parametric regions of the guided-mode resonances, can be directly visualized. It is shown that the linewidths of the resonances can be controlled by the grating modulation amplitude and by the degree of mode confinement (refractive-index difference at the boundaries). Examples presented of potential uses for these elements include a narrow-line polarized laser, a tunable polarized laser, a photorefractive tunable filter, and an electro-optic switch. The guided-mode resonance filter represents a basic new optical element with significant potential for practical applications.
1,166 citations
01 May 1985
TL;DR: In this article, an exact formulation of the grating diffraction problem without approximations is presented, using a series of fundamental assumptions, which reduces to the various existing approximate theories in the appropriate limits.
Abstract: Diffraction characteristics of general dielectric planar (slab) gratings and surface-relief (corrugated) gratings are reviewed. Applications to laser-beam deflection, guidance, modulation, coupling, filtering, wavefront reconstruction, and distributed feedback in the fields of acoustooptics, integrated optics, holography, and spectral analysis are discussed. An exact formulation of the grating diffraction problem without approximations (rigorous coupled-wave theory developed by the authors) is presented. The method of solution is in terms of state variables and this is presented in detail. Then, using a series of fundamental assumptions, this rigorous theory is shown to reduce to the various existing approximate theories in the appropriate limits. The effects of these fundamental assumptions in the approximate theories are quantified and discussed.
989 citations
TL;DR: In this article, a dielectric surface-relief grating is analyzed using rigorous coupled-wave theory and the analysis applies to arbitrary grating profiles, groove depths, angles of incidence, and wavelengths.
Abstract: Diffraction by a dielectric surface-relief grating is analyzed using rigorous coupled-wave theory. The analysis applies to arbitrary grating profiles, groove depths, angles of incidence, and wavelengths. Example results for a wide range of groove depths are presented for sinusoidal, square-wave, triangular, and sawtooth gratings. Diffraction efficiencies obtained from the present method of analysis are compared with previously published numerical results. To obtain large diffraction efficiencies (greater than 85%) for gratings with typical substrate permittivities, it is shown that the grating profile should possess even symmetry.
967 citations
References
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TL;DR: In this paper, a coupled wave analysis of the Bragg diffraction of light by thick hologram gratings is given, analogous to Phariseau's treatment of acoustic gratings and to the dynamical theory of X-ray diffraction.
Abstract: A coupled wave analysis is given of the Bragg diffraction of light by thick hologram gratings, which is analogous to Phariseau's treatment of acoustic gratings and to the “dynamical” theory of X-ray diffraction. The theory remains valid for large diffraction efficiencies where the incident wave is strongly depleted. It is applied to transmission holograms and to reflection holograms. Spatial modulations of both the refractive index and the absorption constant are allowed for. The effects of loss in the grating and of slanted fringes are also considered. Algebraic formulas and their numerical evaluations are given for the diffraction efficiencies and the angular and wavelength sensitivities of the various hologram types.
5,244 citations
502 citations
TL;DR: In this paper, the propagation of electromagnetic waves along open periodic, dielectric waveguides is formulated as a rigorous and exact boundary-value problem, and the characteristic field solutions are shown to be of the surface-wave or leaky-wave type, depending on the ratio of periodicity to wavelength (d/lambda).
Abstract: The propagation of electromagnetic waves along open periodic, dielectric waveguides is formulated here as a rigorous and exact boundary-value problem. The characteristic field solutions are shown to be of the surface-wave or leaky-wave type, depending on the ratio of periodicity to wavelength (d/lambda). The dispersion curves and the space-harmonic amplitudes of these fields are examined for both TE and TM modes. Specific numerical examples are given for the cases of holographic layers and for rectangularly corrugated gratings; these show the detailed behavior of the principal field components and the dependence of waveguiding and leakage characteristics on the physical parameters of the periodic configuration.
452 citations
Abstract: The problem of diffraction at a sinusoidally stratified dielectric grating is treated. The analysis of the reconstruction process from a hologram formed in a “thick” photographic emulsion leads to this problem, but it may also occur in other areas. A rigorous solution of this problem is presented for both polarizations of the electric wave. The solution is evaluated numerically for values of the different parameters that are typical for holograms. It is shown that the amplitude of the diffracted light has a maximum if the light is incident at the Bragg angle, a feature already observed experimentally. Results are given for different values of the period as well as the thickness of the grating and for both polarizations.
256 citations
TL;DR: In this paper, a general coupled-wave formalism describing the multi-wave diffraction properties of thick gratings is presented, which is applicable to refractive-index-modulated and/or absorption-modified gratings of any modulation strength.
Abstract: A general coupled-wave formalism describing the multiwave diffraction properties of thick gratings is presented. The analysis is applicable to refractive-index-modulated and/or absorption-modulated gratings of any modulation strength. The gratings may be slanted, nonuniform with thickness, nonsinusoidal, and lossy. The incident wave (of arbitrary polarization) may be at any angle of incidence including all Bragg angles. Example multiwave diffraction efficiency characteristics are calculated for some representative grating thicknesses and refractive-index modulations for sinusoidal, square-wave, and sawtooth gratings.
158 citations