The propagation of a surface plasmon polariton on a planar metal surface perturbed by N equally spaced rectangular grooves, each with the same width but with varying depths, is investigated by the finite-difference time-domain method. For a linear dependence of the depth of the nth groove on n, the transmissivity of the surface plasmon polariton and of the power radiated into the vacuum above the surface, as functions of its frequency, consist of N equally spaced dips and peaks, respectively. These are the signatures of the surface plasmon polariton analog of a Wannier-Stark ladder.

We present a method for generating a one-dimensional random metal surface of finite length L that suppresses leakage, i.e. the roughness-induced conversion of a surface plasmon polariton propagating on it into volume electromagnetic waves in the vacuum above the surface. Perturbative and numerical simulation calculations carried out for surfaces generated in this way show that they indeed suppress leakage.

The method for designing an one-dimensional surface that acts as a Lambertian diffuser was described. Simulations were performed where the wavelength of the incident light was changed by plus and minus 10% from its original value of λ = 612.7 nm. The surfaces generated on the basis of different b (characteristic length) parameters were also considered. The scattered intensity showed little sensitivity to the large b parameter. The method showed desired scattering pattern when tested with rigorous computer simulations.

We measure and calculate the optical response of a structure consisting of a square array of subwavelength silicon posts on a silicon substrate at telecommunication wavelengths. By the use of the reduced Rayleigh equations and the Fourier modal method (rigorous coupled wave analysis) we calculate the reflectivity of this structure illuminated from vacuum by normally incident light. The calculated reflectivities together with experimentally determined ones, are used to test the accuracy of effective medium theories of the optical properties of structured silicon surfaces, and to estimate the effective refractive index of such surfaces produced by a homogeneous layer model.