出典:Wiktionary
出典:Wikipedia
出典:『Wikipedia』 (2011/02/28 19:28 UTC 版)
An echelle grating (from French, échelle, meaning stairs or ladder) is a type of diffraction grating which is characterised by a relatively low groove density but is optimized for high diffraction orders. Echelle gratings are, like other types of diffraction grating, used in spectrometers and similar instruments, such as HARPS, and numerous other astronomical instruments.