The Performance of Acoustic-Optical $Q$-switched Mode-Locking 1.34 $\mu$m Nd:GdVO$_{4}$ Laser

A diode-end-pumped $Q$ -switched mode-locking $\hbox{Nd:GdVO}_{4}$ laser operating at 1.34 $\mu{\hbox {m}}$ with an acousto-optical (AO) Q-switch in a compact V-type cavity was realized in our experiment for the first time. When the AO Q-switch repetition rate was 10 kHz, the maximum average output power of 750 mW and the pulse energy of 75 $\mu\hbox{J}$ were obtained at the maximum incident pump power of 9 W. The mode-locking modulation depth of about 100% was obtained at certain pump power over the threshold. The mode-locked pulse inside in the $Q$-switched pulse had a repetition rate of 341 MHz, and its average pulsewidth was estimated to be about 350 ps. A developed rate equation model for the $Q$ -switched and mode-locked lasers with an AO Q-switch were proposed by using the hyperbolic secant functional methods. The results of numerical calculations of the rate equations were in good agreement with the experimental results.