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Abstract: As important components in deep-ultraviolet (DUV) optics, especially 193nm lithographic systems, high-reflectivity (HR) mirrors with excellent optical properties and long lifetimes are needed urgently. In this study, we designed and produced three HR coatings for 193nm on fused quartz substrates: Al2O3/AlF3 coating, LaF3/AlF3 coating and a double stack mirror with combined Al2O3/AlF3 and LaF3/AlF3. The reflectance of the Al2O3/AlF3 coating with 14 layer pairs reached 98.0% at 193nm. However, the absorption of Al2O3 prevented the reflectance to increase further. The maximum reflectance of the LaF3/AlF3 coating with 15 layer pairs reached 98.1%, with initial micro-cracks formation. The reflectance decreased as the number of layer pairs increased to 16 because of numerous micro-cracks. The mirror with combined Al2O3/AlF3 and LaF3/AlF3 coatings which combined their advantages obtained a reflectance of 98.8% at 193nm after deposition. This value could still reach 98.5% at 4 months after deposition and remain stable thereafter. Therefore, the combined coating of Al2O3/AlF3 and LaF3/AlF3 is an excellent candidate for practical application. [Copyright &y& Elsevier]

Abstract: In the pursuit for 355nm high laser resistant dielectric coatings, layer-pair number of 10 and 15 LaF3/AlF3 high reflectors with and without SiO2 undercoat were prepared on BK7 substrates. The results indicate considerable increase in 355nm laser-induced damage threshold (LIDT) for samples with undercoat. The samples were analyzed in Normalized Electric Field Intensity distribution, total stress, damage depth and damage morphology, revealing that SiO2 undercoat benefits fluoride coatings by shielding substrate defects and reducing coating defects. [Copyright &y& Elsevier]