Investigations of transmitting optical components for CO2-laser-radiation

Since the early days of laser physics and laser radiation sources the optical components such as mirrors, windows, output couplers, beamsplitters and lenses limit the performance of high power and high energy laser radiation sources and their applications as well. The continuous trends /1,2/ towards industrial laser radiation sources with increased output power, improved beam quality and easy beam modulation requires a corresponding improvement in the power-handling capability of the optical components. The optical components usually take advantage of the use of thin film coatings /3,4/. These thin film coatings are widely used in a variety of applications either as structural overcoats or as functional coatings. The former case implies thin films on machine tools to decrease wear and protective overcoats on optical components to shield surfaces from an adverse environment. The latter case implies thin films on optical components for reflection modifications and wavelength selective or polarization sensitive uses as for interference filters and related components. A successful thin film coating claims for the survive of an optical component in an operating environment at least to the extent resulting to an improvement over a similar uncoated component.