X-ray waveguide arrays: tailored near fields by multi-beam interference

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• 作者：Q. Zhong ; M. Osterhoff ; M. W. Wen ; Z. S. Wang and T. Salditt
• 刊名：X-Ray Spectrometry
• 出版年：2017
• 出版时间：March/April 2017
• 年：2017
• 卷：46
• 期：2
• 页码：107-115
• 全文大小：1277K
• ISSN：1097-4539

文摘

A novel 1-D X-ray waveguide, the Mo/C waveguide array (WGA), is introduced to tailor the optical near field distribution by precisely designed and controlled multi-beam interference at 19.9 keV hard X-ray energy. Seven precisely controlled guiding layers with optimized layer thickness variation were fabricated by high-precision direct-current magnetron sputtering of amorphous carbon (C) and molybdenum (Mo). The thickness variations are designed in such a way to introduce the desired phase shifts between the guided output beams, to act as a quasi-focusing device. The WGA and the layer thicknesses are characterized by X-ray reflectivity, transmission electron microscopy, and measurement of the synchrotron radiation far-field intensity pattern. Based on the measurements and simulations, a reliable Mo/C multilayer layers combination can be verified. With the layers thicknesses, simulations inside the WGA and in the optical near field behind it show that multi-beam interference with the designed phase shifts lead to a relative beam intensity of 0.59 in a quasi-focal plane 0.08 mm behind the exit, with a spot size of 23.8 nm. Copyright