echelle grating


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echelle grating

(ay-shel ) A diffraction grating with very fine lines ruled much farther apart than in other gratings. Such a grating has very high resolution but only over a fairly narrow wavelength band. The resolving power at a given wavelength depends primarily on the total ruled width and the angles of incidence and refraction; a high resolution can be obtained with coarse ruling if the grooves are properly shaped (see blazed grating). The echelle grating of the echelle spectrograph is used at high-order diffraction to give larger angular dispersion. Since the high orders overlap, cross dispersion with, for example, a second grating must be used. The second grating is a standard grating with its direction of dispersion at right angles to that of the echelle; the spectral images of the different orders can then be separated and stacked above one another at the detector.
Collins Dictionary of Astronomy © Market House Books Ltd, 2006

echelle grating

[ā′shel ‚grād·iŋ]
(spectroscopy)
A diffraction grating designed for use in high orders and at angles of illumination greater than 45° to obtain high dispersion and resolving power by the use of high orders of interference.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
References in periodicals archive ?
Planar echelle grating spectrometers based on silicon nanophotonic platform have widely been studied in the recent years [7,8].
However, these methods can not be applied to finite and aperiodic elements such as echelle grating spectrometers.
A planar echelle grating spectrometer based on a Rowland mounting is illustrated in Figure 1(a).
The Echelle grating spectrometers designed for operation in high orders and high angles of incidence and diffraction, can provide high resolution in a more compact size and cover a much wider spectral range than conventional grating spectrometers [16].
Echelle grating spectrometers for inductively coupled plasma-optical emission spectrometry.
It also utilizes the echelle grating principle, where multiple orders of diffraction are separated by a cross-dispersive prism before they are imaged onto a CCD.
On the other hand, the Echelle grating spectrometers, designed for operation in high orders and high angles of incidence and diffraction, can provide high resolution in a more compact size and cover a much wider spectral range than conventional grating spectrometers [19].
HIRES also uses a 2,048-by-2,048 CCD, fed by three high-dispersion echelle gratings. Its 3/4-meter (30-inch) f/1.0 camera, designed by Harlan Epps, consists of two large corrector lenses, a 1-meter (40-inch) lightweight spherical mirror, and a field flattener.