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<title>Optical waveguide-grating filters</title>

1993; SPIE; Volume: 2108; Linguagem: Inglês

10.1117/12.165439

1996-756X

Robert Magnusson, Peter Wang,

Photonic Crystals and Applications

The guided-mode resonance characteristics of planar dielectric waveguide gratings with arbitrary grating slant are discussed. These all-dielectric structures can operate as high- efficiency, narrow-line reflective filters. Expressions and graphs defining the resonance regimes and the resonance locations and their separations for TE and TM modes are given. It is shown that the typically asymmetric filter response found when the filter is in asymmetric waveguide-grating geometry can be made nearly symmetric by proper choice of the thickness. A three-wave analytical solution for the case of normal incidence on an unslanted waveguide grating is derived and verified by comparison with rigorously calculated results. Example results describing the resonance behavior under Gaussian beam illumination show that if the angular spectrum of the Gaussian beam can be accommodated within the angular corridor of the waveguide-grating filter, a high-efficiency resonance can occur. There are numerous potential applications of the guided-mode resonance effects described in this paper such as laser resonator mirrors and narrow-line reflection filters as well as new thin-film antireflection resonant structures, polarizers, and electro-optical switches.