Bendable grating for monochromatization of extreme-ultraviolet light

Gratings used in laboratory applications such as compensated and non-compensated monochromators have usually a plane geometry and require additional optical elements, mirrors, to focalize the selected spectral component. An active grating, whose curvature radius can be adjusted with a suitable mechanism, can at the same time select a spectral component and focalize it, reducing the number of mirrors in the apparatus. In this paper, we present the mechanical configuration and the optical properties in the extreme ultraviolet of a low-cost active grating. The system has been tested in the 13-50 eV region, showing good optical properties and high efficiency, and the shape of the bent grating has been analyzed using a wavefront sensor. The proposed system could be used both in table-top experiments and in large scale facilities.