The differential (angle-resolved) light scattering characteristics of spheres deposited on an optically smooth polished nickel surface were studied. In the experimental work a He–Ne laser beam (632.8 nm) illuminated individual polystyrene spheres of diameters 0.50, 1.09, 2.02, and 4.10 μm. The laser beam was directed onto the surface at 45° angle of incidence and focused to 15-μm 1/e2 diameter. A ring/wedge photodiode detector array centered about the specularly reflected beam collected the light scattered into twenty one ring-shaped elements ranging from ~17° to 62° from the specular direction. For comparison with experiment a theoretical model which partially uncoupled the scattering by the surface and the particle was developed based on extensions of Lorenz-Mie theory. The scattering measurements showed reasonable agreement with the model and indicated that the formulation can be adapted for first-order predictions of light scattering by spherical particles on optically smooth surfaces.
© 1988 Optical Society of AmericaPDF Article