A new type of optical filter is predicted theoretically and verified experimentally. The filter operates under guided-mode resonance conditions in a thin-film waveguide grating. A high-efficiency reflection filter response is produced at the Brewster angle at which TM reflection is classically prohibited. Low-reflectance sidebands are obtained that are adjacent to the resonance peak induced by the Brewster effect in the neighborhood of the resonance peak. A double-layer waveguide grating yields 94% experimental reflectance at the thin-film Brewster angle for a Gaussian laser beam with TM polarization at the 1064-nm wavelength.
© 1998 Optical Society of America
(050.1970) Diffraction and gratings : Diffractive optics
(260.5740) Physical optics : Resonance
(310.0310) Thin films : Thin films
(310.2790) Thin films : Guided waves
(350.2460) Other areas of optics : Filters, interference
R. Magnusson, D. Shin, and Z. S. Liu, "Guided-mode resonance Brewster filter," Opt. Lett. 23, 612-614 (1998)