The evolution of a picosecond optical pulse in a mode‐locked Nd : glass laser is primarily affected by the construction of the resonator components. By paying attention to what have been thought of as minor details in the design of the laserhead, such as mounting of the flashlamps and laser rod, virtually 100% reliability and remarkable reproducibility have been achieved. Furthermore, we have studied how the pump power, mirror alignment, and saturable dye concentration affect the reliability and have found that these parameters must be critically controlled if reproducibility is desired.