A planar dielectric film waveguide with a substrate of a nearly-free-electron metal has an ordinary diffraction grating etched on its surface. The reflection of a light beam incident on the grating from the cover is investigated as a function of the angle of incidence. A perturbation procedure is used for the determination of the resulting absorption spectra. The angular location and the depth of the antiresonance in the angular response of the reflection coefficient are used to obtain estimates of the average thickness of the dielectric film and the relative amplitude of the grating.
© 1999 Optical Society of America
(130.6010) Integrated optics : Sensors
(260.3910) Physical optics : Metal optics
(300.1030) Spectroscopy : Absorption
(310.2790) Thin films : Guided waves
(350.2770) Other areas of optics : Gratings
S. R. Seshadri, "Absorption spectra of a dielectric grating on a metal substrate," J. Opt. Soc. Am. A 16, 922-929 (1999)