Role of Lasers in Linear Accelerators

While time-dependent electromagnetic fields using microwave technology have been exploited for decades in acceleration and manipulation of charged particle beams, modern lasers stand poised to be exploited for these purposes with great promise. The advent of compact sub-picosecond terawatt lasers has renewed the interest in phenomena that involve scattering or collective interaction of lasers with relativistic particles for various purposes such as diagnostics and control of beams, ultra-high gradient particle acceleration, laser-driven high brightness particle sources, etc. We will give examples of laser-linac interaction already in use or being contemplated in such areas as TeV-scale gamma-gamma colliders, laser monitoring of beams, laser injectors and prospects for laser acceleration of particles.