Thallium Iodide Coatings for Potassium Chloride for 9.27Micrometers.

摘要

Five three-layer antireflection coatings for potassium chloride incorporating thallium iodide were investigated. The center layers considered were NaF, ThF4, and KCl. The coatings were tuned for 9.27 micrometers. The window absorption was typically 0.5%. This is a factor of five over the absorption of state of the art coatings at 10.6 micrometers. This increase in absorption is extremely significant. The power handling capability of a window scales with absorption and these absorption measurements indicate that halid windows for operation at 9.27 micrometers must be significantly derated. Two approaches for systematically investigating possible antireflection coating designs for the case of three layers are presented.