Light is an electromagnetic wave phenomenon described by the same theoretical principles that govern all forms of electromagnetic radiation. | Fundamentals of Photonics Bahaa E. A. Saleh Malvin Carl Teich Copyright 1991 John Wiley Sons Inc. ISBNs 0-471-83965-5 Hardback 0-471-2-1374-8 Electronic CHAPTER RAY OPTICS POSTULATES OF RAY OPTICS SIMPLE OPTICAL COMPONENTS A. Mirrors B. Planar Boundaries C. Spherical Boundaries and Lenses D. Light Guides GRADED-INDEX OPTICS A. The Ray Equation B. Graded-lndex Optical Components C. The Eikonal Equation MATRIX OPTICS A. The Ray-Transfer Matrix B. Matrices of Simple Optical Components C. Matrices of Cascaded Optical Components D. Periodic Optical Systems Sir Isaac Newton 1642-1727 set forth a theory of optics in which light emissions consist of collections of corpuscles that propagate rectilinearly. Pierre de Fermat 1601-1665 developed the principle that light travels along the path of least time. 1 Light is an electromagnetic wave phenomenon described by the same theoretical principles that govern all forms of electromagnetic radiation. Electromagnetic radiation propagates in the form of two mutually coupled vector waves an electric-field wave and a magnetic-field wave. Nevertheless it is possible to describe many optical phenomena using a scalar wave theory in which light is described by a single scalar wavefunction. This approximate way of treating light is called scalar wave optics or simply wave optics. When light waves propagate through and around objects whose dimensions are much greater than the wavelength the wave nature of light is not readily discerned so that its behavior can be adequately described by rays obeying a set of geometrical rules. This model of light is called ray optics. Strictly speaking ray optics is the limit of wave optics when the wavelength is infinitesimally small. Thus the electromagnetic theory of light electromagnetic optics encompasses wave optics which in turn encompasses ray optics as illustrated in Fig. . Ray optics and wave optics provide approximate models of light which derive their validity from their .
