A pulsed laser beam is used to create apertures in a layer on a back side
of a substrate that includes a microlens array on a front side thereof.
The pulsed laser beam is focused in a vacuum spatial filter. A profile of
the pulsed laser beam that emerges from the vacuum spatial filter is
converted to a top hat profile. The laser beam having the top hat profile
is diffused. Finally, the pulsed laser beam having the top half profile
that has been diffused is impinged through the microlens array on the
front side of the substrate and onto the layer on the back side of the
substrate. Related apparatus for creating the apertures and microlens
array products are also described.