Ultrahigh-Intensity Optical Slow-Wave Structure for Direct Laser Electron Acceleration

We report the development of corrugated slow-wave plasma guiding structures with application to quasi-phase-matched direct laser acceleration of charged particles. These structures support guided propagation at intensities up to 2×1017W∕cm2, limited at present by our current laser energy and side leakage. Hydrogen, nitrogen, and argon plasma waveguides up to 1.5cm in length with a corrugation period as short as μ35μm are generated in extended cryogenic cluster jet flows, with corrugation depth approaching 100%. These structures remove the limitations of diffraction, phase matching, and material damage thresholds and promise to allow high-field acceleration of electrons over many centimeters using relatively small femtosecond lasers. We present simulations that show that a laser pulse power of 1.9TW should allow an acceleration gradient larger than 80MV∕cm. A modest power of only 30GW would still allow acceleration gradients in excess of 10MV∕cm.