Mode-locked YAG:Nd3+ laser with a high output energy and brightness

A description is given of a YAG:Nd³⁺ laser with an unstable confocal resonator operating in the mode-locked regime. The resonator was from a 100% reflecting 2-m radius of curvature convex mirror and a concave glass substrate having a 4-m radius of curvature, which served as an exit mirror. A solution of dye № 3274u in dichlorethane was used as a saturable filter. The latter had an initial transmission of 30%. For an active medium volume of ~5 m³ the energy of a train of ultrashort pulses was 150 mJ, that of the maximum pulse in the train being 50 mJ. The pulse duration was ~40 psec. The radiation divergence was close to the diffraction limit, having a value of ~0.3 mrad.