Reflection and Refraction
This chapter describes a variety of phenomena occurring when a light wave passes from one medium to another. Light refraction is the most commonly observed phenomenon, but any type of wave can be refracted when it interacts with a medium. The chapter provides the general features associated with the propagation, reflection and refraction of light in isotropic media. The laws of refraction and reflection can be derived in several different ways; for example, from Huygens’s principle, Fermat’s principle, and electromagnetic theory. The electromagnetic approach provides not only the angles of reflection and refraction but also the fractions of reflected and transmitted energy and the phase change on reflection. The Fresnel equations describe the reflection and transmission of electromagnetic waves at a planar interface. They give the reflection and transmission amplitude coefficients for waves polarized parallel and perpendicular to the plane of incidence.