Development of 10-TW high-contrast laser system for laser-ion acceleration

Yogo, Akifumi; Inoue, Norihiro*; Sakaki, Hironao; Fukuda, Yuji; Jinno, Satoshi   ; Kanasaki, Masato; Kiriyama, Hiromitsu; Shimomura, Takuya; Ogura, Koichi; Mori, Michiaki; Bolton, P.; Kondo, Kiminori

The laser-ion acceleration can be complicated by the presence of an amplified spontaneous emission (ASE) pedestal at a leading edge of the high-intensity laser pulse. Several attempts have been made to decrease the ASE level by using a plasma mirror or a OPCPA laser system combined with a saturable absorber: J-KAREN. In this work, we propose another way to improve the main pulse-ASE ratio by using a double-CPA bypass line system. We have developed a new laser line consisting of a pulse compressor, a saturable absorber, a pulse stretcher and a Ti:Sap. multi-pass amplifier. The most remarkable feature of this system is that the bypass line can be installed into a conventional TW laser system.