High-contrast, high-intensity laser pulse generation using a nonlinear preamplifier in a Ti:sapphire laser system

Kiriyama, Hiromitsu; Mori, Michiaki; Nakai, Yoshiki; Shimomura, Takuya*; Tanoue, Manabu*; Akutsu, Atsushi; Kondo, Shuji; Kanazawa, Shuhei; Okada, Hajime; Motomura, Tomohiro*; Daido, Hiroyuki; Kimura, Toyoaki; Tajima, Toshiki

We report on a high-contrast, high-intensity Ti:sapphire chirped-pulse amplification system that incorporates a nonlinear pre-amplifier based on optical parametric chirped-pulse amplification (OPCPA) for use in experiments where relativistic effects dominate the physics. By cooling the Ti:sapphire crystal in the final amplifier down to 77 K, the chirped-pulses are amplified to 2.9 J at 10 Hz repetition rate without thermal lensing effect. Pulse compression down to 19-fs duration obtained after amplification indicates a peak power of 80 TW. With the OPCPA, the temporal contrast is significantly improved to better than 710 in a few picoseconds interval prior to the main laser pulse.