Method for generating ultrashort pulses

A system for generating ultrashort pulses, comprising:

• a first laser source generating a master beam having ultrashort pulses;
• at least one second laser source generating at least one slave beam;
• an optical gate material disposed on the path of the master and slave beams, the intensity of the slave beam upstream of the optical gate material being lower than that of the master beam upstream of the optical gate material, the optical gate material and the pulses of the master beam being chosen so as to induce a Kerr effect when the master beam passes through the optical gate material, the Kerr effect producing a modulation of the phase of the slave beam in association with the pulses of the master beam when the slave beam passes through the optical gate material;
• and
• a complementary optical device for transforming the modulation of the phase of the slave beam into a modulation of an amplitude thereof, so that the ultrashort pulses of the slave beam generated downstream of the optical gate material and the pulses of the master beam downstream of the optical gate material are superimposed temporally;
• and
• an Optical Parametric Chirped-Pulse Amplification (OPCPA) amplifier, wherein the pulses of the master beam downstream of the optical gate material is used as a signal beam of the OPCPA amplifier and the pulses of the slave beam downstream of the optical gate material is used as a pump beam of the OPCPA amplifier.