Photon acceleration in laser-plasma interaction

The results of numerical calculation of photon acceleration(photon frequency up shift)in the plasma wakefield driven by asymmetric laser pulses were presented.It is found that the maximum frequency up shift of the accelerated photons depends on the pulse shape and pulse width.There is an optimum pulse width and pulse rising width.There also exists an upper limit on plasma electron density to get the maximum photon frequency up shift.This will be helpful for further study about laser-plasma particle acceleration mechanism.