题　目：Wideband multilayer mirrors with minimal layer thicknesses variation
主讲人：Igor V. Kozhevnikov（莫斯科晶体学研究所Leading Scientist）
时　间：5月18日（周一），晚上6:30
地　点：物理馆512会议室
语　言：英语
主讲人简介：Igor V. Kozhevnikov莫斯科晶体学研究所的leading scientist，他是国际X射线薄膜元件理论设计和X射线结构表征的顶尖专家。1980年在莫斯科国立大学获硕士学位，1987年在列别杰夫物理研究所（莫斯科）获博士学位，2014年在莫斯科晶体学研究所物理学和数学学科获得俄罗斯最高学位。他发表了150余篇期刊论文，目前的研究领域包括X射线和极紫外光学，物质结构表征的X射线测量分析方法。
讲座简介：Wideband multilayers designed for various applications in hard X-ray to Extreme UV spectral regions are based on a layered system with layer thicknesses varying largely in depth. Brief review of wideband multilayers applications in different areas of X-ray optics (concentration of synchrotron radiation, X-ray and EUV astronomy, EUV lithography) is presented. Our approach to designing wideband multilayers is also discussed. Because the internal structure of a thin film depends on its thickness, this will result in multilayers in which material properties such as density, crystallinity, dielectric constant and effective thickness vary from layer to layer. This variation causes the fabricated multilayers to deviate from the model and negatively influences the reflectivity of the multilayers. In the talk we describe a way to solve this problem by developing designs of wideband multilayers with strongly reduced layer thickness variations in depth, without essential degradation of their optical characteristics.