An end pumped all internal reflection small-sized slab picosecond laser amplifier

An end pumped all internal reflection small-sized slab picosecond laser system amplifier is proposed and demonstrated based on the common Nd:YAG crystal. A cylinder lens is introduced to pre-compensate for the one-dimensional thermal effect caused by the high power pumping laser. The maximum output powers of 6.6 and 6.3 W are obtained at the absorbed pumping power of 25 W without and with a cylinder mirror, and the corresponding optical conversion efficiencies are about 10.4% and 9.3% respectively. The measured M ² factors along the slow and fast axes are 1.71 and 2.47 respectively. The instability of the maximum output laser is below 0.8% (RMS) within measuring time up to 15 min. It is demonstrated that the all internal reflection slab can support long enough optical gain distance to realize the signal laser amplification for the newly developed crystal even with small size and low doped concentration. (letter)