We investigate the focusability of intense coherent soft-x-ray radiation generated by high-order harmonic conversion. The 27th-harmonic wave at 29.6 nm is focused by an off-axis parabolic mirror with a SiC/Mg multilayer coating. Focal-spot images are observed from the visible fluorescence induced by the soft-x-ray photons on a Ce:YAG scintillator. We demonstrate focusing of the soft-x-ray beam to a 1-μm spot size with a peak intensity of 1×1014 W/cm2 , which is to our knowledge the highest ever reported in the soft-x-ray region.
© 2004 Optical Society of America
Hiroki Mashiko, Akira Suda, and Katsumi Midorikawa, "Focusing coherent soft-x-ray radiation to a micrometer spot size with an intensity of 1014 W/cm2," Opt. Lett. 29, 1927-1929 (2004)