Ingve.Simonsen@ntnu.no, Phone: þ47 73 59 34 17, Fax: þ47 73 59 77 10The scattering of light from a weakly rough random silver surface characterized by a double rectangular power spectrum is studied by numerical simulations. This power spectrum can support both the enhanced back and forward scattering phenomena, which for weakly rough surfaces, are both related to the excitation of surface plasmon polaritons. Here we review these phenomena and present new results from a numerical study of the dependence of the diffuse scattering on the amplitudes (g i , i ¼ 1, 2) of the two rectangular portions of the power spectrum. It is found that there exist an optimal range of ratios, g 2 /g 1 , over which forward scattering peaks can be observed. By just changing the correlations along the interface, while keeping all other parameters like roughness, polarization, and angle of incidence unchanged, the fraction of the incident light that is scattered diffusely can be as large as 16%, while for other parameters as small as 1%. Moreover, a change in the correlation function only, can result in a 3.5 times increase in the amount of light that is absorbed at the weakly rough metal interface (s ¼ 10 nm).ß 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim 1 Introduction Electromagnetic wave scattering from randomly rough surface has been a field of intensive research for more then a century [1][2][3][4][5]. During this time period significant progress has been made, but still open questions remains, in particular when it comes to dealing with effects of multiple scattering and two-dimensional surfaces. The continuous interest in this problem is not only due to the fundamental scientific issues involved, but is equally prompted by the wide range of applications that depends upon it. Such applications include radar and telecommunication technology, remote sensing, astrophysics, photovoltaics, medical applications, as well as more recently nanotechnology, and plasmonics.A number of perturbative approaches has been developed for the scattering from randomly rough surface, and so have various computer simulation approaches [4]. Even if a formally exact solution to the two-dimensional scattering problem exists (in the form of integral equations), it is very computational demanding to utilize directly. However, for one-dimensional roughness, such rigorous computer simulation approaches can readily be used with confidence [4,6] often without too much demand on computer time. With such