High Spectral and Spatial Resolution Soft X-ray/XUV VLS Spectrographs

We report the implementation of three high-resolution VLS-grating spectrometers intended for laboratory applications: (i) an inherently stigmatic (imaging) broadband (12.5–30 nm) spectrograph, which uses the synergy of an aperiodic normal-incidence multilayer mirror and a plane grazing-incidence VLS grating; (ii) a scanning spectrometer/monochromator of the Hettrick–Underwood type with a constant deviation angle and a nearly constant focal distance at wavelengths λ < 30 nm; (iii) a flat-field 0.5-m long spectrograph of the Harada type. Broadband (11–14 nm) aperiodic Mo/Be multilayers were designed for extending the range of the imaging spectrograph to 11 nm. Numerical techniques were developed to calculate interference lithography configurations that provide the desired line density variation across the aperture of plane/concave VLS gratings.