Compact dual-band spectrograph

Abstract

A concept and design method of a dual-band flatfield spectrograph is presented. In the proposed optical scheme, the working range of wavelengths is divided into two subranges. A reflection holographic grating is used in the first subrange, and a transmission concave holographic grating is used in the second one. Both of them are aberration-corrected flat-field gratings. As an example, a scheme of spectrograph for spectral range from 278 to 560 nm is considered.