A systematic experimental and theoretical study of first-order grating coupling to surface plasma waves existing at an air–Ag interface is presented. The experiment extends beyond previous work to grating depths comparable with the grating period. The grating profiles range from sinusoidal to rectangular. For TM-polarized incident radiation this grating depth range includes the entire spectrum of surface-plasma-wave-radiation coupling—from underdamped, to nearly 100% coupling, to overdamped and the disappearance of the resonance from the zero-order reflectance measurements. Strong polarization and absorption effects are observed for the deepest gratings. A simple theoretical model, based on the Rayleigh hypothesis and retaining only resonant diffraction terms without a small-signal approximation being made, provides good agreement with the experimental results.
© 1991 Optical Society of America
Original Manuscript: May 17, 1990
Manuscript Accepted: October 18, 1990
Published: April 1, 1991
Saleem H. Zaidi, M. Yousaf, and S. R. J. Brueck, "Grating coupling to surface plasma waves. I. First-order coupling," J. Opt. Soc. Am. B 8, 770-779 (1991)