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Thermal Effects Analysis In High-power Diode Tranverse Pumped Cs Vapor Lasers

Posted on:2014-08-12Degree:MasterType:Thesis
Country:ChinaCandidate:J B LuoFull Text:PDF
GTID:2268330425957145Subject:Optics
Abstract/Summary:PDF Full Text Request
Being a new class of laser device, diode pumped alkali vapor lasers (DAPLs) have obtained a rapid development in recent years. They have both the advantages of gas lasers and solid lasers, which possess some desirable features such as high quantum efficiency, good optical quality and narrow-line-width (several MHz). These lasers have potential applications in laser cooling, directional energy transmission, material processing, atmospheric propagation and it is also promising in achieving near-infrared laser with high power and high beam quality. During the past decades, several experiments about DPALs have been carried out worldwide with some excellent results. For the longitudinal pumping, researchers have obtained some excellent results with maximum output power of48Watts. While pursuing higher power of output laser, the researchers set a physical model on transverse pumping because of the limitation of pump power on longitudinal pumping model. In the model of transverse pumping, the thermal effect will be more remarkable because of higher power of pumping laser and some researchers decrease the thermal effect with pulsed pumping way and flowing gain medium. So far, there are fewer resesrch works on the thermal effect of transverse pumped DPALs, so it is significant to do the research on the thermal effect of DPALs with transverse pumping model.On the basis of our previous works on the spatial temperature distributions of DPALs with two longitudinal pumping lasers and thermal lensing effect, combining with the kinetic models, we set a model to describe the temperature distribution in the cylindrical gain medium of a transverse pumped cesium laser. We simulate the physical model with the finite difference method to describe the temperature distribution of every position in the gain medium. Because of the light abosorbtion of the cylindrical gain medium and the appropriate initial-value problem, there is still a difference between the experiment and simulation results. But it is also an effective way for the future research on the thermal effect of high power pumped DPALs. On the basis of the results of above cylindrical medium and zining yang’s kinetic model on a side pumped alkali vapor laser. We establish a physical model to analysis the temperature field in the cuboid gain medium of a transverse pumped cesium laser. Assuming the pump light to be a Gaussian beam and the nonlinear abosorbtion of medium, using method of Runge-Kutta in Matlab, We get the dependences of the pump power, the beam waist and the absorption coefficient on the temperature distribution. The results show that increasing pump power, decreasing the beam waist and increasing the absorption coefficient will influence the the temperature and its gradient. The results provide a theoretical way for understanding and improving the thermal effect and the output performance of high power pumped DPALs.
Keywords/Search Tags:diode pumped alkali vapor lasers, thermal effect, temperature distribution, longitudinal pumping configuration, side-pumped configuration
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