Direct amplification of picosecond pulses in F2- : LiF crystals

An amplifier of picosecond pulses with an output power up to 10¹⁰ W and an energy up to 30 mJ at 1180 nm is developed on the basis of F₂^- : LiF colour-center crystals. A 3–5-ps, 0.03-mJ probe pulse at 1.18μm was obtained upon intracavity SRS conversion in a passively mode-locked Nd³⁺ : KGd(WO₄)₂ laser. The F₂^- : LiF crystals were pumped by 1053-nm nanosecond pulses from a Nd : YLF laser, amplified in a GLS-22 phosphate glass to an energy of 5 J. The probe SRS pulses were amplified in a four-crystal two-cascade amplifier based on F₂^- : LiF crystals with the total length of the active medium of 360 mm, by using counterpropagating pump beams. The dependences of the output radiation energy on the pump and input signal energies are measured.