Abstract

Mie scattering is a problem which has attracted a lot of attention recently. Most experiments have been done on sphere solutions and are mainly of the far field pattern. In this work we report measurements of the far field intensity from a He-Ne laser (λ = 633 nm) produced by a sapphire sphere (n = 1.7659) with a radius of 0.635 cm. The technique used to measure the scattered light was a photographic one in which we used the body of a commercial photographic camera without any lens. A fringe pattern with a good contrast was measured at 90° with a uniform spacing of 59 μrad. Inside the first rainbow (<4°) the fringe pattern is more complicated with a further period of ~200 μrad. The observed fringe pattern was explained with a geometric optic theory. At 90° the fringe pattern arises from the interference of a reflected ray off the sphere with another ray whose path has one chord inside the sphere. Inside the first rainbow the observed pattern is explained with the interference of three (four) rays for the p- (s)-polarization waves. These rays, also called glory rays, explain the observed fringe pattern without any diffraction effects.

© 1989 Optical Society of America