An in-plane light scattering setup that is capable of measuring large azimuthal scattering angles is presented. This type of measurement makes it easier to probe large <b>k</b><sub>∥</sub> at a fixed <b>k</b><sub>⊥</sub> value (<b>k</b><sub>∥</sub> and <b>k</b><sub>⊥</sub> are momentum transfer vectors parallel and perpendicular to the surface, respectively). Therefore the system allows us to explore small lateral scale and large vertical roughness (~λ, the wavelength of the probe beam) of a rough surface. In-plane intensity measurements from a rough backside Si wafer and a Cu thin-film surface are reported. The structure factor that is related to surface roughness parameters is obtained from the measured in-plane intensity profiles. Both scalar (Beckmann–Kirchhoff) and vector (Rayleigh–Rice) theories have been applied to interpret the experimental data. The roughness parameters obtained from the scattering measurements are compared with those measured by atomic-force microscopy.
© 2000 Optical Society of America
(050.1960) Diffraction and gratings : Diffraction theory
(240.5770) Optics at surfaces : Roughness
(290.5820) Scattering : Scattering measurements
(290.5880) Scattering : Scattering, rough surfaces
Tansel Karabacak, Yiping Zhao, Matthew Stowe, Bill Quayle, Gwo-Ching Wang, and Ton-Ming Lu, "Large-Angle In-Plane Light Scattering from Rough Surfaces," Appl. Opt. 39, 4658-4668 (2000)