Nonlinear Optics in Relativistic Plasmas and Laser Wake Field Acceleration of Electrons

Science  26 Jul 1996:
Vol. 273, Issue 5274, pp. 472-475
DOI: 10.1126/science.273.5274.472


When a terawatt-peak-power laser beam is focused into a gas jet, an electron plasma wave, driven by forward Raman scattering, is observed to accelerate a naturally collimated beam of electrons to relativistic energies (up to 109 total electrons, with an energy distribution maximizing at 2 megaelectron volts, a transverse emittance as low as 1 millimeter-milliradian, and a field gradient of up to 2 gigaelectron volts per centimeter). Electron acceleration and the appearance of high-frequency modulations in the transmitted light spectrum were both found to have sharp thresholds in laser power and plasma density. A hole in the center of the electron beam may indicate that plasma electrons were expelled radially.