Toward a terawatt-kilohertz repetition-rate laser

We present the different problems related to the amplification of ultrashort pulses at high repetition rate. Phase distortion, gain narrowing and thermal effects are studied in detail. We demonstrate, for the first time, that thermal effects in ultrashort pulse amplifiers can be harnessed and positively exploited in the laser design resulting in the production of diffraction limited beams. We demonstrate that peak powers at the terawatt-level amplification at a kilohertz repetition rate is readily conceivable.