grism

Blend of grating +‎ prism.

• Rhymes: -ɪzəm

grism (plural grisms)

1. A combination of diffraction grating and prism used to obtain spectra from selected parts of an image.

   Synonym: grating prism

   The advantage of grisms is that the same camera can be used both for imaging (without the grism) and spectroscopy (with the grism) without having to be moved.

   • 1987, Daniel J. Schroeder, Astronomical Optics, Academic Press, page 302:

     If this grism is placed in an ƒ/4 beam at s = 120 mm, the plate factor P ≈ 1100 Å/mm.

   • 1994, T. M. Herbst, J. T. Rayner, “First Experiences With A Solid ZnSe Grism for Near Infrared Astronomy”, in Ian S. McLean, editor, Infrared Astronomy with Arrays, Springer,, page 515:

     As the name implies, grisms are a combination of a transmission grating and a prism. One common configuration uses the refraction at the grism surface to redirect nonzero diffractive orders along the original optical path.

   • 2010, Frederick R. Chromey, To Measure the Sky, Cambridge University Press, page 382:

     The grism usually consists of an SR transmission grating mounted on the hypotenuse of a right-angle prism. […] Volumetric phase holographic grisms, which are capable of relatively high angular dispersions, have begun to appear.

• Grims, grims