Stigmatic coma free VUV devices for high resolution line profiles measurements

Abstract

Optical devices for line profile measurements must have a symmetrical instrumental profile to allow the use of classical deconvolution methods. Such devices must be then coma free and simultaneously the astigmatic curvature must be eliminated. In a first approach we consider a modified version of a Rowland circle set-up, and in a second one, a new type of stigmatic and coma free spectrometer fitted with spherical holographic gratings each of them covering a restricted spectral range.