Low Absorptance Metallic Coatings for Metallic Substrates.

摘要

The program resulted in producing the fabrication technology that is required for high-energy 10.6micrometer laser programs now underway. Polishing and coating techniques for metallic substrates were developed and the deposition of metallic coatings to reproducibly create metal mirror surfaces with low absorptance of a wavelength of 10.6micrometer was investigated. The basic task was one of expanding and transferring to metal substrates the technology developed by Bennett and Ashley for fused silica substrates. Metal substrates of molybdenum, TZM,and beryllium-copper were polished to a surface roughness of from 12 A to 15 A rms and overcoated with ultra-high-vacuum silver and ggold. Absorption coefficients obtained were as low as 0.0064. The basic finishing technique that is now employed is acid etch stress relieving and controlled grinding,modified conventional polishing techniques,sputtering of similar metallic film,and modified conventional polishing. (Modified author abstract)