Characterization of pulsed Nd:YAG active/passive mode-locked laser

The influence of the distance of an active modulator to one of the resonator's end mirrors is investigated both theoretically and experimentally and is found not to be critical for high-gain lasers. The effect of the active modulator on the pulse length of an active/passive mode-locked Nd:YAG laser is discussed qualitatively. Threshold, stability, pulse length, and output energy are investigated experimentally with respect to their dependence on modulation power of the active modulator, dye concentration of the passive modulator, and resonator length mismatch. At a repetition rate of 10 Hz the best achievable stability for the pulse-train energy was ± 1 percent with a single pulse length of 25 ps. The resonator length has to be maintained with an accuracy of
\pm 100 \mu
m.