【化】 衍射光栅
【医】 衍射[光]栅, 绕射[光]栅

[ noun ]
optical device consisting of a surface with many parallel grooves in it; disperses a beam of light (or other electromagnetic radiation) into its wavelengths to produce its spectrum
<noun.artifact>

Diffraction \Dif*frac"tion\, n. [Cf. F. diffraction.] (Opt.)
The deflection and decomposition of light in passing by the
edges of opaque bodies or through narrow slits, causing the
appearance of parallel bands or fringes of prismatic colors,
as by the action of a grating of fine lines or bars.

Remarked by Grimaldi (1665), and referred by him to a
property of light which he called diffraction.
--Whewell.

{Diffraction grating}. (Optics) See under {Grating}.

{Diffraction spectrum}. (Optics) See under {Spectrum}.

Grating \Grat"ing\, n. [See 2d Grate.]
1. A partition, covering, or frame of parallel or cross bars;
a latticework resembling a window grate; as, the grating
of a prison or convent.

2. (Optics) A system of close equidistant parallel lines or
bars, esp. lines ruled on a polished surface, used for
producing spectra by diffraction; -- called also
{diffraction grating}.

Note: Gratings have been made with over 40,000 such lines to
the inch, but those with a somewhat smaller number give
the best definition. They are used, e. g., to produce
monochromatic light for use in optical instruments such
as spectrophotometers.
[Webster 1913 Suppl.]

3. pl. (Naut.) The strong wooden lattice used to cover a
hatch, admitting light and air; also, a movable Lattice
used for the flooring of boats.