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A blazed diffraction grating reflecting only the green portion of the spectrum from a room's fluorescent lighting. For a diffraction grating, the relationship between the grating spacing (i.e., the distance between adjacent grating grooves or slits), the angle of the wave (light) incidence to the grating, and the diffracted wave from the grating is known as the grating equation.
An ultrasonic grating is a type of diffraction grating [1] produced by the interference of ultrasonic waves in a medium, which alters the physical properties of the medium (and hence the refractive index) in a grid-like pattern. The term acoustic grating is a more general term that includes operation at audible frequencies.
Figure 1: Schematic layout of a White-light Interferometer. A CCD image sensor like those used for digital photography is placed at the point where the two images are superimposed. A broadband “white light” source is used to illuminate the test and reference surfaces. A condenser lens collimates the light from the broadband light source.
The generated refractive index, (2), gives a diffraction grating moving with the velocity given by the speed of the sound wave in the medium. Light which then passes through the transparent material, is diffracted due to this generated refraction index, forming a prominent diffraction pattern. This diffraction pattern corresponds with a ...
The recorded light pattern is a diffraction grating, which is a structure with a repeating pattern. A simple example is a metal plate with slits cut at regular intervals. A light wave that is incident on a grating is split into several waves; the direction of these diffracted waves is determined by the grating spacing and the wavelength of the ...
which is the generalized diffraction grating equation. Here, θ m is the angle of incidence, φ m is the angle of diffraction, λ is the wavelength, and m = 0, 1, 2... is the order of diffraction. Under certain conditions, d m ≪ λ, which can be readily obtained experimentally, the phase term becomes [7] [10]
An echelle grating (from French échelle, meaning "ladder") is a type of diffraction grating characterised by a relatively low groove density, but a groove shape which is optimized for use at high incidence angles and therefore in high diffraction orders. Higher diffraction orders allow for increased dispersion (spacing) of spectral features at ...
A diffraction grating can be considered to be a multiple-beam interferometer; since the peaks which it produces are generated by interference between the light transmitted by each of the elements in the grating; see interference vs. diffraction for further discussion.