A free electron laser (FEL) converts the kinetic energy of a relativistic electron beam into laser light by passing the electron beam through an array of alternating magnets called an undulator. Unlike most other types of lasers, the frequency of the emitted laser light from an FEL can be changed continuously, allowing for wavelengths that are not available any other way. The tunability of an FEL opens new applications, including medical surgeries (see Figure 1), materials processing, advanced microchip manufacturing and nondestructive testing not possible with conventional lasers. In addition to being tunable, FELs have superior beam quality and can scale to much higher laser power than conventional lasers. A high power FEL based on a high current electron beam can be used for military purposes. The US Navy investigating a megawatt (MW) class FEL for use as a ship defense system (shown in Figure 2). Niowave has proposed a 40 MeV, 500 mA superconducting accelerator that can drive a MW-class shipboard FEL.