Approaching 10/sup 19/ W/cm/sup 2/ intensity at sub-kHz repetition rate

Summary form only given. The relativistic nonlinear optics is a fundamentally new optical regime, where the product of the laser intensity times the square of the wavelength exceeds /spl sim/10/sup 18/ (W/cm/sup 2/)/spl mu/m/sup 2/. In the last few years, laser-matter interaction at relativistic laser intensity has been studied extensively, which lead to the demonstration of many new phenomena such as relativistic self-focusing, nonlinear Thomson scattering and MeV particle acceleration. These experiments, however, were done with low-repetition-rate/single-shot lasers. In a previous paper, we demonstrated for the first time that relativistic intensity pulses could be generated at 1 kHz repetition rate. In this paper, we showed that 10/sup 19/W/cm/sup 2/ can be produced with a high repetition rate laser, which is much more stable and compact than the low repetition rate lasers.