Treatment with Ray Optics

Abstract

Calculations in technical optics are often done with a technique called raytracing. This is a treatment of optical systems in the framework of ray optics. It provides a particularly clear, if incomplete, view of the properties of optical systems. Strictly speaking, light propagation needs to be treated by taking the wave nature of light into account. The difference is that waves give rise to diffraction and interference phenomena which are disregarded in ray optics. Whenever the geometrical dimensions of the problem are so small as to become comparable to the wavelength of light, the ray optic treatment breaks down. This is the case in single-mode fibers.