Skip to main content
U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

Realisation of an accurate and repeatable wavelength scale for double subtractive monochromators



Malcolm G. White


We present the results and discussion of two methods for achieving a higher degree of wavelength accuracy of double grating monochromators. In particular, we assessed the benefits of using differential evolution curve fitting techniques to minimize wavelength uncertainties associated with the manufacture of lead screws in sine-bar driven monochromators. Absolute wavelength-scale uncertainties better than {plus or minus}0.1 nm can be realized using this technique. We also report the realization of an accurate and repeatable wavelength scale, using a novel calibration technique, that is applicable to a wide range of monochromators. We present results demonstrating the robustness of the technique by realizing an absolute wavelength scale, across four grating sets from 250 nm to 1600 nm, with scale uncertainties within {plus or minus}0.02 nm and repeatable to {plus or minus}0.005 nm.


accurate, monochromator, repeatable, wavelength


White, M. (2012), Realisation of an accurate and repeatable wavelength scale for double subtractive monochromators, Metrologia, [online], (Accessed May 25, 2024)


If you have any questions about this publication or are having problems accessing it, please contact

Created October 30, 2012, Updated November 10, 2018