TWO-DIMENSIONAL VARIABLE LINE SPACE GRATINGS: PRODUCTION AND APPLICATION

摘要

In the present work, various varied line space (VLS) gratings and reflection zone plates (RZPs) are analysed for their suitability in highly sensitive soft X-ray micro-spectroscopy. The need for high efficiency suggests a two-dimensional focus or straightened focal line whose sharpness and residual curvature will determine the quality. One- and two-dimensional VLS structures feature an attractive trade-off between a sufficient optical performance and a strongly relaxed fabrication, due to moderate line densities, which are easily accessible by e-beam or laser-scan lithography. We found, that based on fanned-out RZP arrays, their continuous limit version produces an almost perfect focal spot or focal line, however, with an aberration level three orders of magnitude better than for the VLS gratings and well below the diffraction limit over large acceptance angles [1].