Homebrew PCBs

>
>To get a as clean beam as possible I have done the opposite to the 
>beam expander:
>
>Using microscope objectives, the beam is focused on a very small pin 
>hole.  Any secondary beams or distortions does not get through the 
>pin hole.  The beam is collimated afterwards with a matching second objective.

Your solution is the same as with an expander: the pin hole has to be 
of 0.06mm diameter (the smallest beam dimension) and you will loose 
the same amount from the perpendicular dimension
as in the expander variant.
Try the led version, it is near square, and the laser's coherency is of no use.
Cristian