George Neil, who leads the Jefferson Laboratory's free electron laser program, says some insiders question whether a free electron laser is even a laser, since its created via a different method than your typical laser. Neil's machine produces coherent laser light directly from an electron beam, allowing it to create any wavelength of light--in other words, any color on the spectrum. Traditional lasers are made from materials that have been pumped with enough energy to make them spontaneously burst with photons. They're confined to just one wavelength of light, which is determined by the molecular structure of the laser material that stores and releases energy.
Because a free electron laser is made out of an electron beam instead of one particular type of material, it is not a prisoner to a molecular structure. An electron beam can be manipulated with magnets to produce a beam of any wavelength. This would allow technicians to adjust the laser to suit the changing marine environment. For example, they could avoid problems with salty, misty air that can interfere with the infrared lasers often used in military laser research.
Once researchers have the electron beam, they inject it into a superconducting particle accelerator to give it a clean, efficient energy boost. Then the beam travels through a device called a wiggler, which literally wiggles the electrons to make them produce a precise type of electromagnetic wave. Voila, you have a laser beam! And you don't want to be in front of one of these beams of light. The Jefferson Laboratory FEL holds the power record at 14 kilowatts--enough to quickly burn through stainless steel.