Bright Field, Dark Field, Lattice Imaging of a Polycrystal

Diffraction Spot Microscopy on grain structure.  Notice that if you leave the small yellow aperature at the center, and move the green aperature over other diffraction spots, then the grain in that particular orientation will "light up" and its modulation will appear.  Now toggle to the "Dark-Field Imaging" mode by  removubg the yellow aperature (by shrinking its radius to zero); notice that only one grain "lights up" but without any modulation.

Created by Wolfram Mathematica 6.0  (01 November 2007)