Calculating parameters of nonplanar diffraction gratings for compact high-aperture spectrographs

Abstract

The optical layout of a compact high-aperture spectrograph is calculated for an operating spectral range of 400–800 nm, an equivalent relative aperture of 1:1.75, and a spectral resolution of no more than 1.5 nm based on a concave nonclassical ruled diffraction grating. The current limitations of ruling and holographic technologies for forming nonplanar high-aperture diffraction concave gratings are considered, and the fabrication of such gratings by precision replication is proposed based on the use of polymer compositions with convex master gratings obtained using a pendulum-type ruling engine.