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Theoretical And Experimental Study On The Characteristics And Control Of The Pulse Width Of A Diode-pumped Solid State Laser

Posted on:2008-01-24Degree:MasterType:Thesis
Country:ChinaCandidate:H K ZhangFull Text:PDF
GTID:2178360242973341Subject:Optical Engineering
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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 health 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 crystal as the gain medium, we have studied the performance of the output laser and the pulse width control in the with acousto-optic Q-switch and GaAs saturable absorbers, respectively. Meanwhile, the coupling wave rate equations are given to theoretically analyze the properties of the above-mentioned Q-switched lasers. The main contents of this dissertation include:I. By using laser-diode as pumping source, a acousto-optic Q-switched Nd:YVO4 laser is realized. Different techniques to control the pulse width of an acousto-optic Q-switched Nd:YVO4 laser have been firstly studied. It is shown that varying the positions of the acousto-optic Q-switched in the laser axis and the pump beam waist in the gain medium provides an efficient means to control the pulse width. A rate equation is introduced, in which the intracavity photon density is assumed to be Gaussian spatial distribution a. The experimental results are consistent with the numerical calculations of the rate equation.II. Different techniques to control the pulse width of an LD-pumped passively Q-switched Nd:YVO4 laser with GaAs saturable absorber have been studied. It is shown that varying the positions of the saturable absorber in the laser axis and the pump beam waist in the gain medium provides an efficient means to control the pulse width. In the theoretical calculation, by considering the thermal lens effect of the gain medium and using the ABCD matrix theory, we give the dependences of the laser beam radii on the pump power, the pump beam radius and the different positions in the laser cavity. And then, by using the rate-equation model, we directly obtain the dependences of the pulse width on the pump power and the pump beam radii. The numerical solutions of the equations agree with the experimental results.
Keywords/Search Tags:GaAs saturable absorbers, Acousto-optic Q-switched, Pulse width control, Gaussian spatial distribution, Rate-equation model
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