Voronov D L, Salmassi F, Meyer-Ilse J, Gullikson E M, Warwick T, Padmore H A
Opt Express. 2016 May 30;24(11):11334-44. doi: 10.1364/OE.24.011334.
A 2500 lines/mm Multilayer Blazed Grating (MBG) optimized for the soft x-ray wavelength range was fabricated and tested. The grating coated with a W/BC multilayer demonstrated a record diffraction efficiency in the 2nd blazed diffraction order in the energy range from 500 to 1200 eV. Detailed investigation of the diffraction properties of the grating demonstrated that the diffraction efficiency of high groove density MBGs is not limited by the normal shadowing effects that limits grazing incidence x-ray grating performance. Refraction effects inherent in asymmetrical Bragg diffraction were experimentally confirmed for MBGs. The refraction affects the blazing properties of the MBGs and results in a shift of the resonance wavelength of the gratings and broadening or narrowing of the grating bandwidth depending on diffraction geometry. The true blaze angle of the MBGs is defined by both the real structure of the multilayer stack and by asymmetrical refraction effects. Refraction effects can be used as a powerful tool in providing highly efficient suppression of high order harmonics.
制造并测试了一种针对软X射线波长范围优化的2500线/毫米多层闪耀光栅（MBG）。涂覆有W/BC多层膜的光栅在500至1200 eV能量范围内的二级闪耀衍射级中表现出创纪录的衍射效率。对该光栅衍射特性的详细研究表明，高槽密度MBG的衍射效率不受限制掠入射X射线光栅性能的常规阴影效应的限制。实验证实了MBG中不对称布拉格衍射固有的折射效应。这种折射会影响MBG的闪耀特性，并导致光栅共振波长的偏移以及根据衍射几何结构使光栅带宽变宽或变窄。MBG的真实闪耀角由多层堆叠的实际结构和不对称折射效应共同决定。折射效应可作为一种强大的工具，用于高效抑制高阶谐波。
