I like to keep a record of related ideas I cross over on the web and the involvement of the Netherlands in laser scanning with prisms. 

Related Ideas

Various hackers have been active in the field of laser scanning microscopes. There is a project
on Hackaday (BlueBeam).  A Swiss hacker space, Gaudilabs build one.
Most are based on components of DVD drives (link to a tear down).
Loetlabor also did an exceptional write down of DVD-based laser scanning microscopy.
They even used a FPGA core to control the laser.
Scanning this literature, I found the following figure;

It shows how the focus is obtained using a four channel photo-diode. One targeted at 850 can be found here Vishay K857PE.  It could be nice to integrate this concept in the laser head. Possible areas would the current place of the photo-diode. Another option would be to place a beam splitter on the point where the laser is colimated, i.e. after the first aspherical lens and before the first cylinder lens.

All this thinking about imaging, made me think of another point of improvement.
Using the camera of an optical mice to record or track the laser beam.
Optical Mice, have camera's which are 30x30 pixels, e.g. ADNS-9500 S9500. The price is in the order of 3 dollars.  The camera's might be large enough to image the spot formed by the laser.
At the moment, I use a CMOS camera from Arducam (OV9281) . These are great but much more expensive (in the order of a 100 dollars). Circuit boards are available for this chip.
Another point of improvement, possible with this chip might be to use it to track the position of the laser head.  A second laser, infrared, would shine on the substrate.  This substrate could be the platform used for printing or the underside of the top of the box that is used to enclose the printer.
Via speckle the position of the laser head can be actively tracked.
Finally, MIT made a nice video of the LaserFactory One. I really like the video. It shows, how extrusion and lasers might be combined one day.  Note, MIT doesn't use laser scanning and moves the bundle using a gantry.

Netherlands

The Netherlands is relocating more assets to laser scanning. Recently, AMSystems got featured by TNO,
in it's line up of 25 spinoffs.   AMSystems, as far as I know, aims to build a laser scanner with a plurality of laser bundles per prism.  They adapted their European patent.
Hexastorm no longer falls under the main claim, as it uses a single bundle, which is really good news.

The Netherlands also supports/is founder of some affiliated startups.
Keiron Technologies, is basically a laser startup which uses laser scanning in combination with laser induced forward transfer. They are affiliated with TNO.
Inphocal is using a Bessel beam in laser scanning.  There is also a startup using Bessel beams for communication known as Aircision.
TNO is also setting up a new startup in STED lithography.

All these startups, including AMsystems, are related to HighTechXL.  I think it is very possible, one or more will use or are using prism scanning.
I have looked for patents but so far did not find a lot.