In this and in the following chapter, we present a very sketchy and incomplete survey of selected applications and illustrations of semiclassical diffraction effects in various branches of physics. The purpose is to furnish a sample of the variety of areas in which manifestations of similar phenomena are present, emphasizing recent developments, as well as to provide some guidance to the literature.

Recent applications of Mie scattering

The reader is referred to previous monographs (van de Hulst 1957, Kerker 1969, McCartney 1976, Bohren & Huffman 1983) for surveys of traditional applications of light scattering by spherical particles. Detailed discussions of coronae, rainbows and glories in meteorological optics are given in Linke & Möller 1961. We review a couple of more recent applications.

Glare spots

When a suspended liquid droplet is illuminated by a parallel light beam and viewed from a relatively close distance (such that it subtends an angle of a few degrees at the observation point), a number of glare spots are seen on its surface; as the observer moves around the droplet, glare spots merge and become colored when rainbow angles are crossed (Tricker 1970, Walker 1976, 1977, 1978). Glare spots are clearly visible in the color pictures of droplets reproduced in Qian et al (1986).

The observer's distance, though close, is still far enough that the field is given by the far-zone expressions (5.1).