ABSTRACT
This chapter presents the basics of refraction and reflection of light rays. These effects are the underlying principles for the function of optical components and systems. Even though light propagates as a transversal wave, its propagation is usually described and characterized in the form of light rays. Such light rays are given by the perpendicular on the wave front and are the basis of geometrical optics. Geometrical optics thus indirectly takes the wave properties or rather the shape of the wave front of light into account. Classical optical elements, such as lenses, prisms, or plates, are based on a simple but fundamental phenomenon that occurs at optical interfaces: refraction. The absorption of light in optical bulk material follows from its material-specific and wavelength-dependent absorption coefficient, leading to an exponential decay of light intensity along the propagation direction. This interrelationship allows for the determination of internal transmittance and absorbance, respectively, of optical bulk material.
