Focusing coherent soft-x-ray radiation to a micrometer spot size withan intensity of 1014 W/cm2

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-sppt 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-mum spot size with a peak intensity of 1 x 10(14) W/cm(2), which is to our knowledge the highest ever reported in the soft-x-ray region. (C) 2004 Optical Society of America.