We present a set of modified rate equations to describe the photon density in a passively <i>Q</i>-switched laser by taking into account the amplified spontaneous emission. Experiments and numerical simulations were carried out on a longitudinally diode-pumped Nd:YVO<sub>4</sub> laser that was passively <i>Q</i> switched using a bulk GaAs wafer as both saturable-absorber <i>Q</i> switch and output coupler. Both sets of results were found to agree with each other very well. Introducing amplified spontaneous emission into the rate equations has proved to be necessary to model accurately the dynamic behavior of passively <i>Q</i>-switched lasers.
© 2004 Optical Society of America
Zhi G. Li, Zhengjun Xiong, Nicholas Moore, Gnian C. Lim, Wei L. Huang, and De X. Huang, "Amplified-spontaneous-emission effects in a passively Q-switched diode-pumped Nd:YVO4 laser," J. Opt. Soc. Am. B 21, 1479-1485 (2004)