Presentation + Paper
20 November 2019 Stability of dielectric multilayer coatings for the Vacuum ultraviolet
Author Affiliations +
Proceedings Volume 11173, Laser-induced Damage in Optical Materials 2019; 1117313 (2019) https://doi.org/10.1117/12.2536346
Event: SPIE Laser Damage, 2019, Broomfield (Boulder area), Colorado, United States
Abstract
Vacuum ultraviolet (VUV) reflective coatings play an important role in many high-tech fields including cosmic physics, space research, life science and synchrotron radiation. In this research, the emphasis are focused on the aging effect of 135.6nm high reflective coatings. The coatings were deposited by resistive heating method based on Lanthanum fluoride (LaF3) and Aluminum fluoride (AlF3). Optical property, surface morphology and roughness, and composition were characterized in different period after deposited. Due to the porous structure and the worse stability of lanthanum fluoride, the content of C and O element increased in LaF3 thin films during aging process. On one hand, the content of C and O are the hydrocarbon contamination from environment and packing boxes. On the other hand, due to the oxidation of film materials, the fluorides will turn into oxyfluoride, which will increase O content. As a result, there will be an increase of absorption and a decrease of reflectance of the 135.6nm high reflective coating. The surface roughness decreased which led to the reduction of scattering and the rise of reflectivity. There will be LaF3-AlF3 mixed layers between interfaces because of interface diffusion, which will further reduce the film performance.
Conference Presentation
© (2019) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Weili Zhang, Zhen Yu, Rui Zhu, Xiaofeng Liu, Kui Yi, Meiping Zhu, and Jianda Shao "Stability of dielectric multilayer coatings for the Vacuum ultraviolet", Proc. SPIE 11173, Laser-induced Damage in Optical Materials 2019, 1117313 (20 November 2019); https://doi.org/10.1117/12.2536346
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KEYWORDS
Reflectivity

Optical coatings

Vacuum ultraviolet

Diffusion

Interfaces

Dielectrics

Scattering

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