Venkes shared detailed instructions of how to make a DIY Laser Scanning Microscope (LSM):
The reason I was thinking of a DVD pick-up is that it houses a laser and a lens capable of projecting a spot of visible laser light small enough to “see” a bit on a DVD. And those bits are very small (320nm)! Furthermore it houses coils to steere the lens (sideways and up and down) and a detection part. This steering is necessary to be able of following the microscopic narrow tracks on a CD or DVD while spinning (sideways moving of the lens) and follow height differences while spinning (up and douwn movement of the lens). You can imagine that folowing the track must be very precise considdering the turning speed and the bit size! These characteristics are exactly what we need!
Project instructables here.
Check out the video after the break.