Düsseldorf 2007 – scientific programme
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K: Fachverband Kurzzeitphysik
K 7: Laserstrahlwechselwirkungen
K 7.2: Talk
Tuesday, March 20, 2007, 15:30–15:45, 6E
High harmonics and attosecond pulses in the relativistic regime — •Teodora Baeva1, Sergey Gordienko2, and Alexander Pukhov1 — 1Institut für theoretische Physik I, Düsseldorf, Germany — 2L. D. Landau Institute for Theoretical Physics, Moscow, Russia
The theory of relativistic spikes explaining the high harmonics generation due to the interaction of a short ultra-relativistic laser pulse with overdense plasma in the relativistic regime is presented [1]. The main analytical results based on microscopic analysis of the plasma as well as PIC simulations are discussed. This theory predicts universal spectrum of the high harmonics, which includes a power-law part, followed by exponential decay. The high harmonic roll-over at γmax3 is parametrically larger than the 4γmax2 predicted by the oscillating mirror model based on the Doppler effect. These predictions of the relativistic spikes were confirmed experimentally [2].
The spikes lead to a train of attosecond pulses in the reflected radiation and propose a way to extract a single attosecond pulse out of the pulse train generated by a multi-cycle driver by means of the mechanism of Relativistic Plasma Control (RPC) [3]. RPC is based on the observation that dynamics of the relativistic spikes is strongly affected by the laser pulse polarization. One can manage the laser polarization in order to control the relativistic spikes and the generation of attosecond pulses. RPC is demonstrated numerically by PIC simulations.
Literature 1. T. Baeva, S. Gordienko, A. Pukhov, PRE 74, 065401(R) (2006). 2. B. Dromey, M. Zepf, A. Gopal et. al., Nature Physics 2, 456 (2006). 3. T. Baeva, S. Gordienko, A. Pukhov, PRE 74, 046404(2006).