Deviation produced by anisotropic prisms

Abstract

A theoretical study has been made of the refraction of rays by prisms cut from anisotropic media. This work has potential applications to the halos of atmospheric optics. Attention is primarily on extraordinary rays in uniaxial crystals, where the prism faces are two cuts parallel to the optic axis, and where one prism face is a cut parallel, the other a cut perpendicular, to the optic axis. In the former case, many results carry over from isotropic prisms, but the absolute minimum of deviation no longer necessarily obtains for refraction in the principal section. In the latter case, minimum projection deviation no longer obtains at symmetrical passage, and there are two maximum projection deviations for each inclination of the incident ray to the principal section.