GOALI: High resolution diffractive x-ray optics

0099893雅各布森电磁辐射的最终焦点是什么？透镜的远场焦点可以通过其0.61倍波长除以透镜的开度角的一半的瑞利分辨率或数值孔径来表征。 为了实现比从可见光激光器和高数值孔径显微镜物镜（例如在共焦显微镜中）获得的聚焦更精细的聚焦，必须显著减小波长，同时仍然保持可观的数值孔径。这可以通过使用短波长的x射线和保持合理高数值孔径的衍射光学来实现。 菲涅耳X射线波带片已经被制造为衍射聚焦光学器件，其在任何波长下产生电磁辐射的最精细远场焦点-在2-5 nm波长下约35 nm的瑞利分辨率。这些波带片是由纽约州立大学斯托尼布鲁克物理和天文学系的一个小组与朗讯科技贝尔实验室唐·田纳特（Don Tennant）的最先进电子束光刻小组进行学术-工业合作制造的，该小组使用附近布鲁克海文国家实验室的国家同步加速器光源（NSLS）进行X射线显微镜研究。波带片由这个合作生产的被用作聚焦光学在三个X射线显微镜系统在NSLS，这些显微镜被用于斯托尼布鲁克组和一些美国和欧洲的研究小组在生物学，聚合物科学，地球科学，胶体化学，环境科学，和其他领域使用X射线显微镜。 考虑到X射线微聚焦在美国同步辐射设施中的重要性日益增加，包括布鲁克海文、阿贡、伯克利、斯坦福大学、康奈尔、威斯康星州大学和路易斯安那州立大学的同步辐射设施，并且这些设施中的每一个都代表2000万至5亿美元的投资，在美国的学术环境中，进一步开发制造尽可能高分辨率波带片所需的工艺似乎是至关重要的。实际上，如果波带片的空间分辨率大大提高，超过现在所能达到的水平，那么X射线显微镜的大量潜在应用（在0.2-1 keV能量范围和1-10 keV能量范围内）将成为可能。PI的研究计划包括以下内容：o他们建议向世界领先的超快X射线脉冲产生小组之一提供波带片：科罗拉多大学/JILA的Margaret Murnane和亨利Kapetyn实验室。这将使非线性光学的第一次探索在X射线波长的设置以外的热核武器。他们建议开发波带片，应该是第一次，使次100纳米分辨率成像常规可用于1-10千电子伏的X射线显微镜。在这个能量范围内的显微镜是生物学和环境科学中微量元素绘图的理想选择，也是检查集成电路中埋置互连缺陷的理想选择。其中高纵横比区域必须成角度以处于布拉格条件下，以实现高聚焦效率和非常高的数值孔径。与纳米压印光刻技术的领先团队之一（德克萨斯大学奥斯汀分校）合作，将我们在精细线宽波带片制造方面的能力与他们的高产量光刻制造技术联合收割机相结合。最终目标是制造有限数量的高分辨率“主”波带片，并使用UTA纳米压印方法制造“一次性”高分辨率波带片。这可能是一个高风险、高回报的科学项目的关键技术：使用x射线自由电子激光获得膜蛋白结构的原子分辨率图。

0099893JacobsenWhat is the ultimate focus of electromagnetic radiation? The far-field focus of a lens can be characterized by its Rayleigh resolution of 0.61 times the wavelength divided by half of the lens' opening angle, or numerical aperture. To achieve a finer focus than that obtained from a visible light laser and a high numerical aperture microscope objective (such as in a confocal microscope), one must significantly decrease the wavelength while still maintaining appreciable numerical aperture. This can be accomplished by using x rays for their short wavelength, and diffractive optics for maintaining a reasonably high numerical aperture. Fresnel x-ray zone plates have been fabricated as diffractive focusing optics that produce the finest far-field focus of electromagnetic radiation at any wavelength - about 35 nm Rayleigh resolution at 2-5 nm wavelength. These zoneplates have been fabricated in an academic-industrial collaboration between a group at the Department of Physics and Astronomy at SUNY Stony Brook that carries out research in x-ray microscopy using the National Synchrotron Light Source (NSLS) at nearby Brookhaven National Laboratory, and the state-of-the-art electron beam lithography group of Don Tennant at Lucent Technologies Bell Laboratories. Zone plates produced by this collaboration are employed as the focusing optics in three x-ray microscope systems at the NSLS, and these microscopes are used by the Stony Brook group and by a number of U.S. and European groups for research in biology, polymer science, geoscience, colloid chemistry, environmental science, and other fields using x-ray microscopy. Given that x-ray microfocusing is growing in importance at U.S. synchrotron radiation facilities including those at Brookhaven, Argonne, Berkeley, Stanford, Cornell, University of Wisconsin, and Louisiana State University, and that each of these facilities represents an investment of $20-500 million, it seems crucial to further develop the processes needed for fabrication of the highest possible resolution zone plates within an academic setting in the U.S. Indeed, a large number of potential applications of x-ray microscopes (both in the 0.2-1 keV energy range, and the 1-10 keV energy range) would become possible if the spatial resolution of zone plates were to be increased significantly beyond what is now attainable. The PIs research program includes the following:o They propose to supply zone plates to one of the world's leading groups in ultrafast x-ray pulse generation: the lab of Margaret Murnane and Henry Kapetyn at the University of Colorado/JILA. This should enable the first exploration of nonlinear optics at x-ray wavelengths in a setting other than that of a thermonuclear weapon.o They propose to develop zone plates that should, for the first time, make sub-100 nm resolution imaging routinely available for 1-10 keV x-ray microscopes. Microscopes in this energy range are ideal for trace element mapping in biology and environmental science, and for inspection of defects in buried interconnects in integrated circuits.o They propose to carry out experimental tests aimed at future development of Bragg zone plates, where high aspect ratio zones must be angled to be on the Bragg condition to achieve high focusing efficiency and very high numerical aperture.o They propose to work with one of the leading groups in nanoimprint lithography (University of Texas at Austin) to combine our capabilities in fine linewidth zone plate fabrication with their technology for high throughput lithographic fabrication. The ultimate goal is to make a limited number of high resolution "master" zone plates, and use the UTA nanoimprint method to fabricate "disposable" high resolution zone plates. This could be a key technology for a high-risk, high-payoff scientific project: the use of x-ray free electron lasers to obtain atomic resolution maps of the structure of membrane proteins.