Temporal contrast and spatial beam quality improvement techniques in a high intensity Ti:sapphire laser system

Kiriyama, Hiromitsu; Mori, Michiaki; Nakai, Yoshiki; Shimomura, Takuya; Tanoue, Manabu*; Akutsu, Atsushi; Okada, Hajime; Motomura, Tomohiro*; Kondo, Shuji; Kanazawa, Shuhei; Sagisaka, Akito; Ma, J.*; Daito, Izuru; Kotaki, Hideyuki; Bulanov, S. V.; Daido, Hiroyuki; Kimura, Toyoaki*; Tajima, Toshiki*

This paper reviews the temporal contrast and spatial beam quality improvement techniques in a high intensity Ti:sapphire laser system that is based on chirped-pulse amplification (CPA). We describe an optical parametric chirped-pulse amplification (OPCPA) preamplifier that is seeded by a cleaned high-energy pulse. It demonstrates a background amplified spontaneous emission (ASE) level of 10 relative to the peak main femtosecond pulse on the picosecond timescale. We also report a cryogenically-cooled Ti:sapphire final amplifier which generates focused peak intensity in excess of 10 W/cm at a 10 Hz repetition rate.