Scaling EUV and X-ray Thomson sources to optical free-electron laser operation with Traveling-Wave Thomson-Scattering

Traveling-Wave Thomson-Scattering (TWTS) allows for the realization of ultra-compact, inherently synchronized and highly brilliant light sources by providing optical undulators with hundreds to thousands of undulator periods from high-power, pulse-front tilted lasers pulses.

With TWTS the realization of optical free-electron lasers (OFELs) as well as incoherent radiation sources with orders of magnitude higher photon yields than classic head-on Thomson sources becomes possible with state-of-the-art technology in electron accelerators and laser systems.

The talk will show how pulse-front tilted, petawatt class laser pulses and relativistic electrons work together in a side-scattering geometry, where laser end electron propagation direction of motion enclose an angle, to realize long but compact optical undulators with centimeter to meter-scale interaction distances at sub-millimeter undulator periods. Example setups of TWTS OFELs emitting ultraviolet radiation are presented which are realizable today with existing technology for electron accelerators and laser systems. Especially the ultra-low emittance of laser wakefield accelerated electron bunches can be exploited to compensate for their one percent level energy spreads. Further an experimental setup is presented to generate the tilted TWTS laser pulses. This setup strategy provides dispersion compensation, required due to angular dispersion of the laser pulse, and is especially relevant when building compact, high-yield hard X-ray TWTS sources in large interaction angle setups.