Monolayers containing subnanometer striations of silica and hafnia to form composite materials at varying ratios are explored as a method to develop high-index dielectric layers with increased laser-induced–damage thresholds (LIDTs). These layers can then be used in multilayer dielectric coatings for short-pulse, high-peak-power laser applications, particularly in regions of the highest electric-field intensity. Fabrication is achieved by means of exposure to two different evaporant vapor plumes, where local exposure to each plume is controlled via shielding to prevent simultaneous exposure. The LIDT of the resulting layers has been evaluated at 1053 nm with 600-fs pulses. The results indicate that such hafnia/silica layers exhibit LIDTs similar to silica for a refractive index of ≤1.65. These results suggest that the use of these layers in locations subjected to high electric-field intensity within multilayer dielectric coatings may significantly improve the LIDT, with this deposition process providing particular benefit for scaling to large-aperture, high-fluence components.

The deformable mirror of the Laser MegaJoule facility is made of a thin coated BK7 substrate requiring strict reflected wavefront specifications in a dry environment. To achieve these specifications, several PIAD coating conditions have been tested and the coating tooling has been optimized. Reflected wavefront results of coated full scale parts, and stress data on samples under various PIAD coating conditions are presented.

Plasma-assisted electron-beam evaporation leads to changes in the crystallinity, density, and stresses of thin films. A dual-source plasma system provides stress control of large-aperture, high-fluence coatings used in vacuum for substrates 1 m in aperture.

Use of high-resolution deposition-rate monitoring and programmatic control of electron-beam position results in improvements in rate consistency and uniformity of source depletion during SiO2 thin-film deposition by electron-beam evaporation.