Strong monochromatic harmonics generated by the interaction of two counter-propagating pulses with a foil target
相对传播的双脉冲激光与薄膜靶作用产生的强单色谐波

This paper studies the strong harmonic generation in the interaction of two conter-propagating pulses with a foil target. When the thin target is irradiated by high-contrast circularly polarized laser pulse, the light pressure push high-density plasma forward.At the same time, because of the role of charge separation field, the ion beam and electron beam bunch well in longitudinal direction, and generate the plasma mirror with a forward movement at relativistic speed. When incidenting on a probe laser pulse on the plasma mirror in the opposite direction, they produce strong monochromatic N-order harmonics by Doppler shift, with the new duration of pulses compressed to 1/N of the original ones. This paper also discusses the effect of the laser and plasma parameters on plasma mirror movement which influences the order of harmonics, and also the effect of the stability of the relativistic plasma mirror on the harmonics.