Stimulated-Brillouin-scattering compression of pulses from an Nd : YAG laser with a short cavity and measurement of the nonradiative relaxation time of the lower active level

A short (~11 cm) cavity of an Nd : YAG laser was Q-switched by LiF : F₂^- and GSGG : Cr³⁺ : Cr⁴⁺ : Nd³⁺ crystals. This resulted in stable generation of short (~2.5 ns) pulses with energies in excess of 6 mJ. Pulses with ~300 and ~150 mJ energies for the first and second harmonics, respectively, and of ~100 ps duration were obtained at the output of a stimulated-Brillouin-scattering compressor and a three-pass Nd : YAG amplifier. A study of the gain recovery after passage of a short saturating pulse through the active element yielded the upper limit (1 ns) of the nonradiative relaxation time of the ⁴I_11/2 lower active level of the neodymium ion.