Abstract

An inherent disadvantage in working at relatively high grating angles in optical emission spectroscopy in order to obtain increased dispersion and higher line-to-background ratios is the presence of multiple orders. If a stigmatic spectrograph (e.g., Jarrell–Ash 3.4-m Ebert) is used, the various orders can be offset or "sorted" by a device such as the Jarrell–Ash "order sorter." The "order sorter" is essentially a low-dispersion spectroscope which projects a vertical spectrum of the source on the slit of the spectrograph. Light of wavelength λ falls on a specific portion of the slit while light of another wavelength, for example 2λ, falls on a different portion. If the spectrograph is stigmatic, the two wavelengths produce images at different levels on the photographic plate corresponding the their different positions on the slit; the length of each image being determined by the width of the "order sorter" slit. In this manner, the spectrum is "sorted" and overlapping orders avoided. However, the multiple orders are still in the focal plane to be recorded by the detector.

Improving the Accuracy of Jarrell-Ash Microphotometers

John A. Detrio and Vincent L. Donlan
Appl. Opt. 13(10) 2236-2239 (1974)

Modification of a Jarrell-Ash Ultraviolet Monochromator to an Infrared Duochromator

K. G. P. Sulzmann
Appl. Opt. 4(9) 1141-1143 (1965)

Stigmatic Plane Grating Spectrograph with Order Sorter

Richard F. Jarrell
J. Opt. Soc. Am. 45(4) 259-269 (1955)

An Order Sorter for High Resolution Spectrographs

E. van Rooyen
Appl. Opt. 5(7) 1117-1119 (1966)

A Simple Order Sorter for Use with Diffraction Gratings Blazed for High Orders

E. H. Pinnington
Appl. Opt. 6(10) 1655-1657 (1967)