Nearly diffraction-limited line focusing of a hard-X-ray beam with an elliptically figured mirror

An elliptical mirror for X-ray microfocusing was manufactured using the new fabrication methods of elastic emission machining and plasma chemical vaporization machining. Surface profiles measured using stitching interferometry showed a maximum deviation around the ideal figure of 7 nm peak-to-valley. The mirror showed nearly diffraction-limited focusing performance, with a 200 nm line width at the focus. Wave-optical calculations, taking the measured surface profile into consideration, reproduced well the measured focusing properties both at and around the beam waist.