C Rechatin1, J
Lefebvre3 and V
d'Optique Appliquée, ENSTA, CNRS, Ecole Polytechnique, UMR
7639, 91761 Palaiseau, France
de Physique des Gaz et des Plasmas, CNRS, UMR 8578,
Université Paris XI, Bâtiment 210, 91405 Orsay cedex, France
de Physique Théorique et Appliquée, CEA, DAM Ile-de-France,
BP 12, 91680 Bruyères-le-Châtel, France
to whom any correspondence should be addressed.
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.