Abstract

The dispersion, resolution, and signal-to-noise ratio in single- and double-pass use of spectrographs are discussed. A theoretical ratio of single- to double pass-dispersion is derived for a non-Littrow spectrograph. The resolution that can be expected is computed by convolution of the appropriate Doppler, Lorentz, and and Schuster line profiles. A method for choosing between single- and double-pass operation to optimize the signal-to-noise ratio for a given resolving power is described. The measured dispersion, resolution, and signal-to-noise ratio of a 5-m vacuum spectrograph using a 12 × 25-cm grating are compared to the computed values. The results indicate that the resolution obtained is essentially the same as the computed values and that double-pass operation can be very efficient for high-resolution spectrographs.

© 1966 Optical Society of America

A Double-Pass Pfund Spectrograph for Solar Research

Walter E. Mitchell and Orren C. Mohler
Appl. Opt. 3(4) 467-478 (1964)

Properties of a Plane Grating Predisperser Used with a Grazing Incidence Vacuum Spectrograph*

H. E. Blackwell, G. S. Shipp, M. Ogawa, and G. L. Weissler
J. Opt. Soc. Am. 56(5) 665-674 (1966)

An Order Sorter for High Resolution Spectrographs

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

Dispersion of a Double-Pass Spectrograph*

T. A. Wiggins and G. D. Saksena
J. Opt. Soc. Am. 48(6) 429-430 (1958)

Resolution and Noise in Fourier-Transform Spectroscopy*

R. A. Williams and W. S. C. Chang
J. Opt. Soc. Am. 56(2) 167-170 (1966)