High-Reflectance Coatings at 193nm

Abstract:

As an important component in 193nm laser system, high-reflectance (HR) coatings with excellent optical and mechanical properties are needed urgently. In this study, we designed and produced three different HR coatings at 193nm, Al₂O₃/ AlF₃ coating, LaF₃/ AlF₃ coating and a double stack mirror with combination of Al₂O₃/ AlF₃ and LaF₃/ AlF₃. With 14 layer pairs, the reflectance of Al₂O₃/ AlF₃ coating could reach 98% which could not get higher duo to the absorption of Al₂O₃. The reflectance of LaF₃/ AlF₃ coatings could achieve 98.13% with 15 layer pairs. When the layer pair increased to 16, the reflectance lessened ascribed to steep rise in scattering loss caused by micro-cracks occurred in the coatings. A mirror with combination of Al₂O₃/ AlF₃ and LaF₃/ AlF₃ could obtain the reflectance of 98.78% as deposited. Even 4 months later the value could still reach 98.47% which was an excellent candidate for practical application.

• Periodical: Advanced Materials Research (Volumes 631-632)
• Pages: 110-115
• DOI: https://doi.org/10.4028/www.scientific.net/AMR.631-632.110
• Online since: January 2013
• Authors: Jian Sun, Wei Li Zhang, Kui Yi, Jian Da Shao
• Keywords: 193nm, Coating, Fluoride, High-Reflectance, Oxide

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