Femtosecond Green Light Generation Using a MgO-Doped Periodically Poled Lithium Niobate Crystal Pumped by a Yb-Doped Fiber Laser

We demonstrate, in this paper, the creation of a femtosecond green laser achieved from a MgO-doped periodically poled lithium niobate crystal pumped by a home-made Yb-doped MOPA laser system. With an incident fundamental average power of 2 W, 820 mW (41 nJ) is produced at 515 nm with pulse duration of ~540 fs, corresponding to conversion efficiency of 40%. The standard deviation of the 515 nm pulse-to-pulse intensity is calculated as 0.007 (normalized), and the average power keeps stable with a root-mean-square value of 0.18% in an eight hour measurement. The spectral characters of the green laser and laser-induced damage thresholds of the crystal are also investigated. This stable laser system provides a compact and portable laser source for two-photon photopolymerization application.