Diamondlike Carbon Coatings for Optical Systems

摘要

Diamondlike carbon (DLC) coatings have been deposited on seven infrared transmitting substrates utilizing three different techniques: ion-beam deposition, rf-plasma discharge, and hollow cathode discharge methods. Optimum deposition parameters for each technique have been established as a function of substrate material. Extensive characterization of the DLC films was also performed. Rutherford backscattering and proton recoil detection techniques were used to analyze carbon and hydrogen content and impurities. These films contain typically 70% C and 30% H. Transmission electron microscopy was used to analyze the crystallinity, void structure, surface microstructure, and thickness of the films which were found to be amorphous and dense. Optical properties such as refractive index, extinction coefficient, and optical band gap of the films were determined by variable angle spectroscopic ellipsometry (VASE) over the special range from 300 nm to 10.6 micrometers. Optical properties were found to be related to the preparation procedure used. The thermal stability, moisture penetration, rain erosion, and sand ballistic impact effects on these DLC films were extensively investigated. The effect of high energy ion radiation on DLC films was studied. Details of preparation methods and characterization of DLC films are presented. Keywords: Protective coatings; Antireflection coatings; Optical coatings; Thin films; Ellipsometry. (KT)