Diffraction grating

-Diffraction grating - optical attachment that separates light into its constituent colors.
-Diffuse lighting - lighting that is low or moderate in contrast, such as on an overcast day.

A diffraction grating is a structure with a repeating pattern. A simple example is a metal plate with slits cut at regular intervals.

The lens is removed and the wafer is moved as closely as possible to the undersurface of the diffraction grating to catch the evanescent light. Naturally the diffracted light is captured as well.

See also: Light, Diffraction, Meter, Type, Wavelength