Q-switching and mode-locking in a diode-pumped frequency-doubled Nd : YAG laser

A new method for obtaining Q-switching simultaneously with mode-locking using one travelling-wave acousto-optic modulator in a frequency-doubled Nd : YAG laser cavity is described. Further shortening of output laser pulses (from 40 to 3.25 ps) is achieved by forming a Kerr lens in the frequency-doubling crystal. At an average power of ~2 W and a Q-switching rate of 2 kHz, the peak power of the stably operating reached ~50 MW.