OPTICAL PATH IN BIREFRINGENT MEDIA AND FERMAT'S PRINCIPLE

Abstract

In this paper we propose a definition for the optical path in birefringent crystals. We apply this definition to light refraction in a crystal-crystal interface by means of Fermat's principle. The result obtained is confirmed by applying Snell's law generalized for crystals and the relation obtained from Maxwell's equations between the direction normal to the wavefront and the ray.