Paper
10 February 1981 Echelle Efficiency And Blaze Characteristics
M. Bottema
Author Affiliations +
Abstract
On the basis of a simple model for diffraction by the groove, we show that the efficiency of an echelle is high in the Littrow arrangement, but becomes markedly less if the angle of deviation between the incident and the diffracted beams is increased. We also show that the height and width of the spectral image change if the directions of incidence and diffraction are interchanged, but that the efficiency remains the same. In general, the direction of maximum efficiency does not coincide with the blaze direction, defined as the maximum of the envelope of the diffracted-light distribution function. The difference depends on the mode of operation of the spectrograph (scanned or stationary spectrum) and typically changes from a fraction of a degree at high orders in the UV to several degrees at low orders in the IR. Experimental evidence agrees qualitatively with these calculations, but a more refined diffraction model may be needed for a quantitative interpretation.
© (1981) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
M. Bottema "Echelle Efficiency And Blaze Characteristics", Proc. SPIE 0240, Periodic Structures, Gratings, Moire Patterns, and Diffraction Phenomena I, (10 February 1981); https://doi.org/10.1117/12.965652
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CITATIONS
Cited by 4 scholarly publications.
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KEYWORDS
Diffraction

Diffraction gratings

Spectrographs

Reflectivity

Mirrors

Moire patterns

Data modeling

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