Research Of The Nonlinear Physical Process Of The Interaction Of Ultra-intense Laser Pulses With Thin Foils

People have been looking for ultra-short, ultra-intense laser pulses in order to explore physics phenomenon in some extreme conditions. Especially, it is easy to attain the relativistic intensity with the appearance of chirped-pulse amplification technique, providing the probability to research the relativistic nonlinear dynamic. However, the relatively low damage threshold of the optical components has stood out to be a bottleneck to block the development of laser technique. The plasma has been a new-style optical medium to control the ultra-intense laser pulses and amplify laser field due to that it has no damage threshold, which has attracted significant interest in recent years.The work is based on the research of Bai-Fei Shen, which maily focused on the nonlinear physical process of the interaction of ultra-intense laser pulses with thin foils. In this paper, both schemes of laser pulses shaping and amplification are proposed. The paper is composed of three parts:Firstly,we describes the model of the interaction of ultra-intense laser pulses with the thin foils, which is solved in a steady state and shown that the dynamic could be realized. It can provide the theoretical foundation of controlling the ultra-intense laser pulses during the laser-plasma interaction.Secondly,Laser-Pulse shaping during the interaction of ultra-intense laser pulses with the ultra-thin foils is considered by a one-dimensional analytic theory and PIC simulation. The analytic results show that the effect of self-consistent nonlinear modulation of the plasma foils on the pulse shortening and steeping. Comparing to a single foil, the double foils could optimize the shaping effect, and a transmitted pulse with both shorter duration and higher amplitude is obtained. The rising with time of the shaped pulses would steep as the peak amplitude of the incident pulses is higher than the smash threshold of the foil.Finally,the trapping of a single laser pulse and Laser-Field amplification are investigated by an analytical theory and 1D-PIC simulation. It is found that the intensity is amplified to 135-fold that of a pump laser in the interaction of a single circularly polarized laser with two targets, consisting of both a thin foil and an infinite solid target laid aside closely. It is shown that the energy oscillation is mainly due to the compression and expansion of the electron layer, and a steady state can be obtained after several oscillations.