The Theory of Forced Double Refraction

Abstract

An attempt is made to better understand the nature of the double refraction in crystals by calculating the forced double refraction induced in rocksalt and KCl crystals through elastic stress (photoelasticity). In a previous paper only the change in the Lorentz-Lorenz force had been taken into account. In this paper is also considered the "potential dip" which is due to the forced anisotropic arrangement of the ionic charges. The formulas are developed according to classical theory and to wave mechanics but they contain too many unknown constants to be checked against experiment.