Application of conventional laser technology to gamma-gamma colliders

A future e−-e+ (electron-positron) linear collider can be configured with perhaps minimal modification to serve as an γ-γ (gamma-gamma) or a e−-γ collider. This is accomplished by Compton-backscattering low energy photons (from a laser source) off of the high-energy electron beams prior to the crossing of the electron beams. However, to be competitive with the e−-e+ configuration, the luminosity cannot be compromised in the process. This requires that the laser source diliver a sufficient number of photons per pulse with a pulse format and rate matching that of the electron beams. As it turns out, this requires an average optical power of 5–15 kW from the laser which is beyond the current state of the art. In this paper, we address how to generate the required pulse format and how the high average power requirement can be met with conventional laser technology. We also address concerns about the survivability of mirrors located near the interaction point. Finally, we list a program of research and development which addresses some of the unknowns in such a system.