Generation of relativistic intensity pulses at a kilohertz repetition rate

By using adaptive optics to correct the wave-front distortion of a 21-fs, 0.7-mJ, 1-kHz laser, we are able to focus the pulses to a $1‐\mathit{\mu }\mathrm{m}$ spot with an $f/1$ off-axis parabolic mirror. The peak intensity at the focal position is $1.5\times {10}^{18} \mathrm{W}/{\mathrm{cm}}^2$, which is to the authors’ knowledge the first demonstration of generating relativistic intensity at a kilohertz repetition rate.