Subnanosecond Nd: YAG laser with multipass cell for SBS pulse compression

Subnanosecond Nd: YAG laser with output energy at 1064 nm up to 1.1 J and pulse repetition rate 10 Hz was developed for applications, related to medical skin treatment. Available pulse durations are 400 – 750 ps. Laser includes master oscillator with pulse duration 5.5 ns, stimulated Brillouin scattering (SBS) pulse compressor, and amplifier system. Original multi-pass scheme provide compression using liquid cell with small overall length ~15 - 20 cm. Overlapping of pump beams during multiple passes along cell leads to several effects, which can produce negative influence on output pulse performance. We develop schemes, where overlapping is eliminated or reduced, and obtain reliable generation of compressed pulses with the same duration and stability, as can be obtained for long (with total length ≥ 70 cm) single-pass SBS compressors.