I saw something about this on a laser faq.   There were also a few pages I
found about students doing this at uni.  I unfortunately no longer have the
links, but try looking for a laser FAQ.

Thomas M¿rch wrote:

>  I know this is kinda off topic, but since this is the only
> hardware/software/everything list that i know of, i'll post it here....
>
>  A couple of years ago, i saw a demonstration of a DSP from Analog Devices,
> wich displayed a rotating logo on a oscilloscope in X/Y mode. I have lately
> been thinking about doing the same thing, but with a laser instead... It
> could be fun to make a rotating (digitaly) clock display (like the opengl
> screensavers that come with WinNT 4.0), that was blown up on the wall...
>
>  I was planning on using some galvanometers (if i can find some cheap)
> (Someone here mentioned that there was some in a videodisc player???) And a
> laser diode, for the light thing..
>  So my questions is:
>
>  1. Anyone got any experience with such an implementation?
>  2. Where do one get hold of galvanometers?
>  3. How fast can one turn a laser led on/off?
>  4. See number 1. :)
>
> I know that it must be some kind of vectorised graphics engine in a DSP (i
> don't think a PIC is fast enough for this one). But besides this i haven't
> got any clues as to how i should attack this little challenge...
>
> - Thomas