Optical properties of infrared transmitting materials (LQ-10 high power laser window program)

The choice of appropriate infrared transmitting materials for high-power laser applications necessitates a knowledge of various optical parameters. It has become important to be able to predict optical parameters from either theoretical or phenomenological models. Considerable progress has been made recently, especially with regard to the frequency dependence of refraction, absorption alpha and photoelasticity. It has been found, for example, that frequency dispersion is important at 10.6 micrometers for all three of the latter quantities in most alkali-halides. For most semiconductors, on the other hand, only the effects on alpha are significant. The mix of existing experimental data with recent theory is now providing us with a view of the magnitude, frequency dependence, and temperature dependence of optical parameters of infrared transmitting materials.