A free-electron laser (FEL) is an accelerator based light source capable of generating coherent, high power radiation with optical properties characteristic of convential lasers such as high spatial coherence and a near diffraction limited radiation beam. While a convential laser uses bound atomic or molecular states as its lasing medium, an FEL uses a relativistic electron beam, thus the term "free-electron". In an FEL, the relativisitic electron beam passes through the periodic magnetic field of an undulator (or wiggler) which results in the stimulated emission of light. The characteristics of the emitted light are determined by the electron beam energy and pulse structure, and the magnetic field characteristics of the undulator. FELs are continuously tunable and can produce high-average and high-peak power. FELs have successfully operated in the microwave, far infrared, mid-infrared, visible, ultraviolet and x-ray ranges.

Additional information about FELs and other FEL Centers can be found at the Free Electron Laser Virtual Library. Information about accelerator based light sources can be found at lightsources.org.

Light Sources at the DFELL

The Duke FEL Laboratory has a storage ring based FEL light source and an FEL based gamma source:

• The OK-4 ultraviolet FEL installed on a 1.2 GeV storage ring provides tunable coherent radiation from 400 nm to 193 nm. [more…]
• The High Intensity Gamma Source (HIGS) produces polarized near mono-energetic high intensity gamma rays through Compton back scattering. [more…]