Improvement of a prepulse contrast of an intense laser pulse by a combination of regenerative and optical parametric chirped pulse amplifiers

In this paper, we present a simple and effective technique, so called REPA (REgenerative amplifier and Parametric Amplifier), that combines the advantage of OPCPA with RA in a CPA laser chain to achieve a prepulse contrast level of more than 10 orders of magnitude with a commercial low-energy pump laser. Typically, pulses from RA with additional Pockels cells have a prepulse contrast of 6 orders magnitude with millijoule level energy. The pulse energy is attenuated to nanojoule level while maintaining the same prepulse contrast. The main pulse is then selectively amplified in OPCPA to millijoule level again.