So-called tabletop accelerators are a holy-grail of high energy/high field physics and, if developed, as indicated by the Department of Energy in the Accelerators for America report, will spur a revolution in particle physics discoveries and also in medical treatments. This is because planned next-generation particle accelerators are still kilometers in size and billions of dollars to build and support, and therefore are only within reach of large research consortia as opposed to typical research Institutions or Universities. In order to address this gap in technology, laser-plasma accelerators have been proposed and demonstrated to accelerate high-charge; high-brightness bunches of electrons to more than 100 MeV, in less than 1 cm. However, while these recent acceleration results have generated enormous international interest and stimulated investigations of laser-plasma acceleration as viable acceleration stages, there are several barriers to practical implementation such as the very low repetition rates (1 shot per second or less), large size, and high cost. To address these issues, we propose a tabletop laser-based accelerator in which a number of fiber lasers are combined to pump an Optical Parametric Chirped Pulse Amplifier capable of generating high energy ultrashort pulses at high repetition rates. This solution increases the repetition rate by several orders of magnitude, and provides with a much more practical laser for driving a laser plasma accelerator. During Phase I a novel fiber laser array system design based on a new method for combining multiple fiber lasers have been developed which allows achieving high pulse energies with relatively few combined amplification channels, thus providing substantially smaller system size and cost. In this Phase II SBIR proposal, this Phase I design will be used to experimentally demonstrate a compact and high average power laser front end capable of driving high energy electron-beam particle accelerators at high repetition rates. This technology holds the potential to one day make compact, tabletop-sized accelerators a reality, and to dramatically increase the rate of acceleration possible with traditional high energy particle accelerators without dramatic increases in machine dimensions. Compact, plasma wakefield particle accelerators would be significantly more economical than current RF-based machines, putting them within reach of a much larger range of university and institutional research labs for basic research and medical applications. Furthermore, the constituent fiber lasers used to pump the optical parametric chirped pulse amplifier scheme can become stand- alone products for use in a variety of material processing tasks, spanning microelectronic and solar device processing.
