A power amplifier for a femtosecond terawatt Cr:forsterite laser system

A three-stage power amplifier is developed for an IR terawatt femtosecond laser system generating 80-fs, 1240-nm pulses with energy of up to 90 mJ, a pulse repetition rate 10 Hz, and the intensity contrast above 10⁶. The efficiencies of different schemes of multipass amplifiers are compared. It is shown that an optical scheme with plane mirrors is optimal for achieving the terawatt power level.