Chapter 27: Geometrical Optics, Chapter 28: Wave Optics

Abstract

Geometrical optics is the study of light without diffraction or interference and is based on Fermat’s principle. We treat light as particles of energy traveling through space. These particles follow trajectories that are called rays. Hence, geometrical optics is oſten called ray optics. Fermat’s principle is a concise statement that contains all the physical laws, such as the law of reflection and the law of refraction, in geometrical optics (Poon and Kim 2006).