Electromagnetically induced guiding of counterpropagating lasers in plasmas

The interaction of counterpropagating laser pulses in a plasma is considere d. When the frequencies of the two lasers are close, nonlinear modification of the refraction index results in the mutual focusing of the two beams. A short (of order of the plasma period) laser pulse can also be nonlinearly focused by a long counterpropagating beam which extends over the entire gui ding length. This phenomenon of electromagnetically induced guiding can be utilized in laser-driven plasma accelerators. [S1063-651X(99)00201-9].