A Recording Echelette Grating Spectrometer for the Near Infra-Red

Abstract

A new prism‐grating spectrometer employing replica echelette gratings and capable of resolving lines from 0.3 cm⁻¹ to 1.0 cm⁻¹ apart in the region 1–25μ is described. Careful shielding and construction of a stable amplifier have so reduced zero unsteadiness as to make possible the direct recording of galvanometer deflections. Atmospheric absorptions have been almost entirely eliminated by circulation of the air in the spectrometer box over chemicals contained in separate boxes.