ABSTRACT
Until the 1940s the need for optical materials was satisfied by bulk optical glass and a small number of halide crystalline materials, because the science of optics dealt mainly with the UV and visible spectral regions. Since that time many new UV, visible, and infrared optical systems have been researched and marketed. This chapter discusses the intrinsic and extrinsic loss mechanisms in optical materials and then goes on to compare the candidate materials and their properties. Crystalline alkali halide materials are grown from the melt by traditional growth techniques. A more modern technique used to achieve higher quality, low loss, scatter-free material for high power applications employs the reactive atmosphere processing treatment. The chapter discusses how the information can be used in making a realistic choice of material for various applications. A number of loss mechanisms occur when electromagnetic radiation in the optical and infrared frequency range is incident on and passes through an insulator or semiconductor.
