High-power Ld End-pumped Q Nd: Yag Laser

Diode-pumped Q-switch solid-state lasers have many advantage such as high efficiency, compactness, high stability, and long lifetime. High peak power ,high repetition rate short-pulse can be obtained by high power diode pumped, which is used comprehensively in the field such as measuring, remote sensing, photoelectric resisting, medical et. We have researched the theory and experiment on Q-switch lasers based on high power diode end-pumped Nd:YAG crystal to suit the requirement of photoelectric resisting.At first, according to the fundamental Q-switch equation, we analyze the Q-switch system, including active Q-switch and passively Q-switch .We have derived simple analytic expression for all of the parameters of optimally coupled laser by using the mathematical technique of LaGrange multipliers. These parameters (which include the optimum reflectively output energy, extraction efficiency, pulse width, peak power, etc) can call be expressed as functions of a simple dimensionless variable z defined as the ratio of the unsaturated small-signed gain to the dissipate (nonsueful) optical less.In experiment, we have designed two Q-switch systems, including accousto-optical actively Q-switched and Cr4+: YAG passively Q-switch system .The experience result can be outlined as follow:l.A maximum of 8.52W of cw output at 1064nm has been obtained by planoconcave cavity .The slope efficiency was 54%. The pulse train with minor pulse width 32ns and frequency 5kHz ,peak power 7.58kW were obtained in accousto-optical Q-switch experience2. The nonuseful loss of cavity were got by measuring the threshold of laser under the different output mirrors . The loss was caused by Prague angle unmatching .3.The pulse train with minor pulse width 22ns and frequency 23kHz ,peak power 3.5kW were obtained in Cr4":YAG passively Q-switch experience .the stability of pulse is 6%.4.We have found and analyzed the phenomenon of pulse modulation and autoecious pulse.