Abstract

In this note we discuss two unusual types of "scattered" radiation that can occur in Littrow-mounted grating monochromators. Here, "scattered" radiation refers to diffracted radiation that reaches the exit slit by paths other than the one for which a monochromator was designed. Such spurious radiation usually will be out of focus at the exit slit and may not be noticeable in many applications. However, its presence can lead to serious error in the measurement of the absorption coefficient of a band, since the intensity at the exit slit for a particular grating angle will be the sum of the desired intensity at the correct wavelength and the spurious intensity at another wavelength.

Littrow-mounted diffraction grating cavity

Haim Lotem
Appl. Opt. 33(6) 930-934 (1994)

Advantages of an off-Littrow mounting of an echelle grating

Ronald Masters, Chunming Hsiech, and Harry L. Pardue
Appl. Opt. 27(18) 3895-3897 (1988)

Critical-point behaviors of gratings in Littrow mountings

Lifeng Li
J. Opt. Soc. Am. A 39(2) 297-305 (2022)

Study of a reflection grating used in Littrow mount

D. M. Capps
Appl. Opt. 56(12) 3293-3302 (2017)

X-ray monochromator designs based on extreme off-plane grating mountings

W. Werner and H. Visser
Appl. Opt. 20(3) 487-492 (1981)