Ld Pumped All-solid-state Q-switched Laser Characteristics Of Theoretical And Experimental Research

Laser-diode (LD) pumped solid-state laser has wide applications in the fields such as laser telecommunication, remote-sensing detection, industry and military as well as healthy due to its advantages such as all solid state, high pump efficiency, small volume and long longevity, and has been paid much attention on.In this dissertation, by using the fiber-coupled laser-diode as the pump source, Nd:YVO₄ and Nd:GdVO₄ crystals as the gain mediums, we have studied the performance of the output pulse and the pulse width control in the passively Q-switched lasers with Cr⁴⁺:YAG and GaAs saturable absorbers, respectively. The characteristics of the LD-pumped doubly Q-switched lasers with acoustic-optic(AO)—Cr⁴⁺:YAG, AO—GaAs and Cr⁴⁺:YAG—GaAs have also been studied, respectively. Besides, the research on the frequency-doubling performance of the periodically poled KTP crystal has been carried out. Meanwhile, the coupling wave rate equations are given to theoretically analyse the properties of the above-mentioned Q-switched lasers. The main contents of this dissertation include:(I) We have presented the performance of an LD-pumped Nd:YVO₄ laser passively Q-switched with Cr⁴⁺:YAG saturable absorber. For different small-signal transmissions of Cr⁴⁺:YAG, different reflectivities of the output mirror and different pump powers, the pulse energy, peak power, pulse width and repetition rate of 1.06μm laser have been measured. Meanwhile, a new rate-equation model for the Q-switched laser is given, in which the transversal and longitudinal distributions of the intracavity photon density, the transversal distributions of the population-inversion density, the saturable absorber ground-state population density and the pump beam are taken into account. The numerical solutions of the rate equations are in agreement with the experimental results.