Simultaneous third and fourth harmonic mode-locking of a Q-switched flashlamp-pumped Nd:YAG laser

A single-rod, high pulse-energy, Nd:YAG laser is presented that is actively mode-locked simultaneously at the third and fourth harmonics of the round-trip frequency and Q-switched after a a prelasing period. The output consists of highly stable pulses, separated by the round-trip time, of about 90 ps duration and 1 mJ energy