Shaposhnikov R A, Polkovnikov V N, Salashchenko N N, Chkhalo N I, Zuev S Yu
Opt Lett. 2022 Sep 1;47(17):4351-4354. doi: 10.1364/OL.469260.
The results of investigations of Ru/Sr multilayer coatings optimized for the spectral range of 9-12 nm are presented in this Letter. Such mirrors are promising optical elements for solar astronomy and for the development of beyond extreme ultraviolet (BEUV) lithography. A near-normal incidence reflectivity of up to 62.3% (λ = 11.4 nm) right after the synthesis is measured. The reflection coefficient decreases to 56.8% after five days of storage in air with a subsequent stabilization of its value. At a wavelength of λ = 9.34 nm, the reflection coefficient is 48.6% after two months of storage in air. To date, to the best of our knowledge, this is the highest reflectivity measured in this spectral range. The possibility of further increasing the reflectivity is discussed.
本文给出了针对9 - 12纳米光谱范围优化的Ru/Sr多层涂层的研究结果。这类反射镜对于太阳天文学以及超越极紫外（BEUV）光刻技术的发展而言是很有前景的光学元件。合成后立即测得近正入射反射率高达62.3%（λ = 11.4纳米）。在空气中储存五天后，反射系数降至56.8%，随后其值稳定下来。在λ = 9.34纳米波长下，在空气中储存两个月后反射系数为48.6%。据我们所知，迄今为止，这是在该光谱范围内测得的最高反射率。文中还讨论了进一步提高反射率的可能性。
