Producing focused intensity of 3/spl times/10/sup 18/ W/cm/sup 2/ with a 1 kHz laser

Summary form only given. Ultrahigh focused intensities (>10/sup 18/ W/cm/sup 2/) is very important for high field physics studies at the relativistic regime. Very small number optics must be used for focusing of kHz laser pulses. However, the focused intensity is limited by the aberration of the optics and the wavefront distortion of the laser system. The laser we used is a home-built 1 kHz Ti:sapphlre laser system. The oscillator of the laser generates broadband femtosecond pulses (120 nm FWHM).