Conception of a single-component broadband high-resolution plane-VLS-grating monochromator

Abstract

We propose a broadband single-element monochromator with a constant deviation angle and fixed slits for the wavelength range of 3–60 nm, which uses a grazing incidence plane varied line-space (VLS) grating with exponential dependence of line frequency across the aperture. Wavelength scanning is performed by translating the VLS grating along its surface. The deviation angle is constant, and the source, input, and output slits are stationary. With an exit slit (or CCD pixel size) of 6 µm, the practical resolving power λ / δ λ = 6000 remains constant throughout the operating range. The proposed scheme is compared with a narrowband specialized monochromator ( 135 ± 4 Å) with the same acceptance angle, in which wavelength scanning is performed by rotating a plane VLS grating, as well as with a Rowland monochromator with a similar acceptance.