Previously difficult or impossible shapes can now be placed on visible imaging optical surfaces using Narrow Ion Beam
Figuring (NIBF). This technique, unlike classical Ion Beam Figuring (IBF), does not substantially roughen the surface.
Furthermore, the method can be used to take optical surfaces to sub-nanometer surface errors and to sub-micron radian
slope errors. A specific set of applications uses NIBF surfaces at a reimaged pupil plane to impart special characteristics
on image creation. Such optics has steep local slope changes over only 1mm scale.