Quasi-monoenergetic electron beams produced by colliding cross-polarized laser pulses in underdense plasmas
Abstract
The interaction of two laser pulses in an underdense plasma has been proven to be able to inject electrons into plasma waves, thus providing a stable and tunable source of electrons. Whereas previous works focused on the 'beatwave' injection scheme in which two lasers with the same polarization collide in a plasma, this present paper studies the effect of polarization and more specifically the interaction of two colliding cross-polarized laser pulses. It is shown both theoretically and experimentally that electrons can also be preaccelerated and injected by the stochastic heating occurring at the collision of two cross-polarized lasers and thus, a new regime of optical injection is demonstrated. It is found that injection with cross-polarized lasers occurs at higher laser intensities.