ABSTRACT
Technological developments in fields, such as astronomical instrumentation, lithography, spectroscopy, biomedical, and so on, have impacted the development and implementation of high-reflectance optical devices. This chapter discusses the traditional and modern aspects of the reflective components. The mirrors as well as lenses can be used in optical systems to change beam directions and to form images. A spherical mirror is free of spherical aberration only when the object and the image are both at the center of curvature or at the vertex of the mirror, fulfilling the conditions of Abbe aplanatic. Ellipsoidal mirrors, whose surface is generated by rotating an ellipse about its major axis, produce an image free of spherical aberration when the image and object are located at each of their foci. Reflecting coatings are an essential part of mirrors, beamsplitters, and prisms. The dielectric coatings are remarkably hard, durable, and abrasion-resistant; that is, the coatings are more robust than metal mirrors.
