Future compact light sources driven by CO₂ lasers

Ongoing research on Compton radiation sources is aimed toward developing university-scale compact x-ray- and gamma-radiation-sources. Novel conceptual approaches are being pursued along different routes: One research direction lies in multiplying the source’s repetition rate, and increasing its average brightness by placing the point of Compton interaction inside an optical cavity. High-gradient plasma-wakefield accelerators are fast becoming a practical reality, offering a new paradigm for compact all-optical Compton sources operating in x-ray- and gamma-regions. Continually bettering the quality of the beam of plasma accelerators promises the achievement of fully coherent Compton x-rays, thereby prompting the evolution of the Compton source to an all-optical free-electron laser. Intense lasers can move the high-energy cut-off limit in a Compton spectrum by efficiently generating high-order harmonics. The ATF’s user- and upgrade- programs based on ultra-fast CO₂ laser technology strongly support all these research thrusts.