Focusing and Wavefront Splitting of an Extreme Ultraviolet Laser with a Tubular Optical Element

A capillary discharge extreme ultraviolet laser is focused and wavefront split at 46.9 nm by a tubular optical element. The reflectivity both simulated measured to be higher than 90% with slight aberration. operating principle of the element for focusing splitting discussed. Dense intense grating-like fringes period ~150 are achieved. method used in this work allows nano-scale processing single-shot exposure mode.