Specifications

Diamond™ GEM, G, & K, Integrator’s Guide
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divided by the beam diameter for each lens greater than 10 to mini-
mize effects of aberration. Also the same guidelines on acceptable
clear apertures and beam diameters given above are still applicable
On gantry based systems, the beam expander can be used to adjust
focus at the work surface. This is accomplished by setting the final
objective lens to exactly it’s back focal length (BFL) from the work
surface (along the middle of the optical axis). The BFL is specified
by the lens manufacturer. Focusing is then done by adjusting the
spacing of the lenses in the beam expander.
Figure 14. Simple Beam Expander
Figure 15. Galilean Beam Expander
Input Beam x
F1
F2
F1
F2
Input
Beam
Input
Beam
Expanded
Output Beam