title: Prepulse-free, multi-terawatt, sub-30-fs laser system.
abstract: We have built a prepulse-free, multi-terawatt, ultrashort pulse laser system, which combines both conventional laser amplification and optical parametric chirped pulse amplification (OPCPA) techniques. By employing an OPCPA system after the regenerative amplifier in a Ti:sapphire chirped pulse amplification laser chain, we have dramatically enhanced the prepulse contrast by 6 orders of magnitude. A prepulse contrast of better than 4.4 x 10-11 has been measured with a high energy broadband pulse of 24 mJ at 10 Hz repetition rate from the OPCPA system. Using a subsequent four-pass Ti:sapphire amplifier, we have achieved an amplified energy of 279 mJ and an ultrashort recompressed amplified pulse duration of 23.5 fs, corresponding to the peak powers for OPCPA and four-pass amplifier of 0.5 TW and 5.9 TW, respectively.
authors.forename: Hiromitsu
authors.initials: H
authors.lastname: Kiriyama
authors.forename: Norihiro
authors.initials: N
authors.lastname: Inoue
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Akahane
authors.forename: Koichi
authors.initials: K
authors.lastname: Yamakawa