If you’re interested in the workings and principles of how energy is focused to create a fine cutting beam, you should definitely check out this video by How its Made. It shows the mirrors used to bounce light around and describes the process of generating photons from electrical energy inside a chamber of pressurised mixture of Nitrogen, Carbon Dioxide and Helium gas. The principles are similar to the laser cutters used by Ponoko to cut plastics, timber and metals.
David is an industrial designer from New Zealand. He contributes a weekly article on personal fabrication for Ponoko. You can follow him on Twitter @dizymac