DURABLE 3-5 MU-M TRANSMITTING INFRARED WINDOW MATERIALS

Properties of 3-5 mu m infrared-transmitting window materials are revi ewed, with an emphasis on durable materials for applications in enviro nments involving moisture, impact by solid and liquid particles, high temperatures and rapid heating rates. Infrared, visible and ultraviole t transmission windows are compared for MgF2, aluminum oxynitride, sap phire, spinel, MgO, Y2O3, calcium aluminate, SiO2, CaF2, LiF, ZnS, ZnS e, GaAs, GaP, Si and Ge. Emission at elevated temperature, reflection and optical scatter are also discussed. A comparison of mechanical and thermal properties is given, as is a brief discussion of rain and par ticle erosion resistance. (C) 1998 Elsevier Science B.V. All rights re served.