Research On Passively Q-Switched Laser With Cr⁴⁺:YAG Crystal

Compared with other lasers, the output of the laser-diode (LD) pumped solid-state laser is special in the high peak power, the high pulse repetition rate and the narrow pulse width. This kind of laser has been widely applied in the fields such as industrial, scientific research, military and medical, due to its advantages such as compact size, high efficient, simplicity and inexpensive. It has become the research focus of scholars from home and abroad.In this dissertation, by taking the fiber-coupled laser-diode as the pump source, Nd3+:YAG crystal as the gain medium, and the Cr4+:YAG storable absorber as the passive Q-switch, as well as by using the end-pumped to Nd3+:YAG crystal, we have studied the performance of the output pulse in the passively Q-switched laser. The main points of this paper can be summarized as follows:1) The development process of the LD pumped solid-state laser are reviewed. The characteristics of Cr4+:YAG crystal and theoretical foundation of Q-switch are analysed.2) The properties of the Q-switched laser have been theoretically analyzed by using of the Coupling rate equations under Gaussian distribution approximation3) The LD-pumped passively Q-switched Nd3+:YAG 1064nm laser has been realized; the output power, pulse repetition rate and pulse width have been worked out, when they at different pumped powers, transmittances of output mirror and cavity lengths; and the experimental results have been theoretically analyzed to a consistent conclusion.4) By considering the thermal effect of the medium, the optimal position of the Cr4+:YAG crystal in the laser cavity have been obtained from the study, and on the basis of this conclusion, the optimal position of the pump source have been found.