Optimum design of a grazing-incidence flat-field spectrograph with a spherical varied-line-space grating

Abstract

A grazing-incidence spectrograph is designed by use of the flat-field image-focusing property of a spherical varied-line-space grating. Optimum grating parameters for mechanical ruling are selected by application of genetic algorithms. Two gratings, one for 2–5-nm and the other for 5–20-nm spectral regions, are designed, and their fabrication tolerances are analyzed.