Diode-pumped Doubly Q-switched Mode-locked YVO₄/Nd:YVO₄ Laser With AO And GaAs Saturable Absorber

All-solid-state lasers have wide applications in micromachining, the materialprocessing, coherent telecommunications, information storage and so on, due to its advantages such as its simplicity, high efficiency, high stability, long longevity, good beam quality and has been paid much attention on.Nd:YVO4 crystal has been widely used as diode-pumped laser media. However, the weak thermal conduction of Nd:YVO4 crystal limited its wide application in high-power laser systems. By using diffusion bonding of a doped laser crystal Nd:YVO4 with a non-doped crystal YVO4, known as the composite crystal, it had been shown that the temperature gradient in the YVO4/Nd:YVO4 composite crystal can be reduced. The employment of a composite crystal has been demonstrated to be a useful method in relieving the thermal lens effect.In this paper, by using both acousto-optic (AO) modulator and GaAs saturable absorber, a diode-pumped doubly QML YVO4/Nd:YVO4/KTP green laser and a diode-pumped doubly QML YVO4/Nd:YVO4 laser is presented. The average output power and the pulse width of the Q-switched envelope have been measured. A rate equation model is used to simulate the performance of this laser, and the numerical solutions agree well with the experimental results. The main contents of this dissertation include:1. Using the three-mirror-folded cavity, laser-diode pumped doubly Q-switched YVO4/Nd:YVO4 laser with both AO modulator and GaAs saturable absorber has been realiaed. The average output power and the pulse width of the Q-switched envelope have been measured. The experimental results show that the doubly QML laser has good stability with the nearly 80% modulation depth. A rate equation model is used to simulate the performance of this laser, and the numerical solutions agree well with the experimental results.2. Using both AO modulator and GaAs saturable absorber, laser-diode pumped doubly Q-switched YVO4/Nd:YVO4/KTP laser has been realiaed. The average output power and the pulse width of the Q-switched envelope have been measured. Especially, by using double-loss modulations (AO and GaAs), the doubly Q-switched and mode-locked green laser can generate more stable pulse train with deeper modulation depth, shorter pulse width, greater pulse energy and higher peak power. A rate equation model is used to simulate the performance of this green laser, and the numerical solutions agree well with the experimental results.The main innovations of this dissertation are as follows:1. we have firstly presented the performance of laser-diode pumped doubly Q-switched YVO4/Nd:YVO4 laser with both AO modulator and CaAs staturable absorber experimentally and theoretically.2. we have firstly presented the performance of laser-diode pumped doubly Q-switched YVO4/Nd:YVO4/KTP 532nm laser with both AO modulator and CaAs staturable absorber experimentally and theoretically.