Atomic layer processing as a platform for ultraviolet coatings

ALD and ALE have emerged as thin-film coating techniques able to address several technical challenges in space instrumentation. This paper will describe recent work that applies these methods to improve the performance and stability of broadband protected-Al coatings, detector-integrated bandpass filter coatings, and narrowband reflective dielectric coatings. Systems that require the use of thin Al films can benefit from ALE methods that can remove the native oxide that would otherwise degrade UV performance. The performance of ALD mirror coatings operating at far UV wavelengths (90–200 nm) is presented in the context of the emerging needs of the Habitable Worlds Observatory. Trends in spatial uniformity are discussed considering the potential requirements of planned coronagraphic instruments. Extension of the same aluminum/fluoride material system to bandpass filters operating in the far UV are also discussed. Finally, we present recent work on new ALD process for high-index materials like LaF3, and present initial results of high-low multilayer stacks which can which can be useful to produce dichroic or narrowband reflective coatings in the UV.