OPTICAL MATERIALS FOR THE INFRARED: CURRENT STATUS

Abstract

“The properties of available optical materials are of critical importance in the design of infrared equipments. The principal uses in laboratory instruments such as spectrometers are for prisms and absorption-cell windows; in field instruments refractive materials are used for large entrance windows and for corrector plates in catadioptric systems. A review is given of the important optical and other physical properties of the materials used in present-day instrumentation, with emphasis on refractive index, transmission region, and mechanical and thermal properties. The current status of availability and usefulness of materials is assessed in terms of the need for prisms transmitting to long wavelengths and windows suitable for field equipments employing photoconductive or thermal detectors. Generally speaking, the situation is much less satisfactory for field equipments than for laboratory equipments.”