One embodiment of an apparatus in accordance With the
present invention is shoWn in FIG. 1 by Way of illustration
and not limitation. Apparatus 10 comprises light source 12
and beam expander 14, Which is disposed adjacent to light
source 12 and betWeen light source 12 and diffractive
element 16. In the embodiment of FIG. 1 diffractive element
16 is a disk having a plurality of openings (see FIG. 2).
Apparatus 10 further comprises holder 20, Which holds