1.1. Terawatt, kilohertz femtosecond laser

Summary form only given. Applications of laser generated ultra-short X ray pulses demand high photon numbers as well as high intensities. The requirement for high intensity on the target makes it necessary to obtain over 1 TW of peak power while keeping over 80% of the light in the diffraction limited spot. While impressive numbers for the peak power can be obtained they are useless if the quality of the whole source is not maintained. Although 10 Hz sources have been used to produce X-rays, the average power is in general low and very few applications of femtosecond X-rays have been demonstrated. We present here a laser system capable of producing over 1 TW pulses at 1 kHz repetition rates while keeping the diffraction limited quality of the pulse.