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.

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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).

A fast simulation method of silicon nanophotonic echelle gratings and its applications in the design of on-chip spectrometers

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.

Study of the matrix effect on the plasma characterization of six elements in aluminum alloys using LIBS with a portable Echelle spectrometer

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].

Study of the matrix effect on the plasma characterization of heavy elements in soil sediments using LIBS with a portable echelle spectrometer

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.

Science with the Keck Telescope