Study of the optical properties of diamond-like coatings prepared by laser-arc

The Laser-Arc as a controlled pulsed arc plasma source was used to prepare DLC-films for optical applications: DLC-films with a thickness of up to 500 nm were deposited on different substrate materials (ZnSe, NaCl, KCl,Ge) using special preparation techniques for enhancing the substrate-film adhesion. Coating was performed at room temperature in a vacuum of 10 high -4 Pa. A special moving substrate holder was used to deposit an all round protective DLC-coating that covers the complete surface of the salt substrates including the rims. The optical properties of the coating were determined by spectrophotometry and laser calorimetry. On the basis of the photometric transmission measurements, the refractive indices were calculaated. The optical absorption at 10.6 Mym ranges from 200 to 900 cm high -1 and depends on the film thickness and on the substrate material. The results demonstrate that the controlled arc evaporation by Laser-Arc is suitable for the preparation of DLC-coatings with o ptical quality.