LASER ACCELERATION OF RELATIVISTIC ELECTRONS USING THE INVERSE CHERENKOV EFFECT

A 580-MW peak power, radially polarized CO2 laser beam (=10.6 m) focused by an axicon accelerated 40-MeV electrons by 3.7 MeV over a 12-cm interaction length (31 MeV/m), using the inverse Cherenkov effect in which a gas is used to slow the light wave. This represents the first direct observation of acceleration using this effect and demonstrates the effectiveness of the radially-polarized-axicon-focused geometry. The observed energy gain agrees with model predictions. © 1995 The American Physical Society.