Diffractive Optical Element (DOE)
Approximately 70% @ 633 nm
Function of aperture and input beam.
Shape convolved with input beam.
100% modulation, producing a speckle-like pattern of uniform intensity.
At focal point of lens, the pattern looks best (convolve with Airy pattern).
Small input yields large speckle, 1 mm diameter beam. Large beam looks best at the focal point of a lens (airy pattern looks better than guassian when convolved with diffuser function). Need multiple unit cells across the beam. Lower number of unit cells makes beam lumpier.