An achromatic soft x-ray imaging system based on a transmission microscope equipped with a pair of Wolter mirrors was constructed. The two Wolter mirrors for the condenser and the objective were fabricated precisely by using an electroforming replication process. The samples were illuminated by broadband high harmonic pulses in the wavelength range of 26 nm to 35 nm via the condenser mirror, and transmission bright-field images without chromatic aberration were formed by the objective mirror. A single-shot image illuminated by a femtosecond laser pulse was recorded at a spatial resolution of about 200 nm. The fundamental capability of the microscope to realize broadband images without chromatic aberration will lead to the development of soft x-ray microscopes with extremely short illumination pulses on the order of attoseconds.

中文翻译：

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宽带软X射线脉冲的单发消色差成像

构建了基于透射显微镜的消色差软X射线成像系统，该显微镜配有一对Wolter反射镜。聚光镜和物镜的两个沃尔特镜通过电铸复制工艺精确制造。样品通过聚光镜在26 nm至35 nm的波长范围内用宽带高次谐波脉冲照射，并通过物镜形成无色差的透射明场图像。飞秒激光脉冲照射的单次图像以约200 nm的空间分辨率记录。显微镜实现宽带图像而无色差的基本能力将导致软X射线显微镜的发展，这种显微镜具有极短的照明脉冲（约10 ns）。