The light intensity distributions on pumped face and end surface in composite slab are simulated with the method of Non-Sequential Mode ray tracing using software Zemax.From the tracing results, we can find that when the pumping beam is on the pumped face, the light intensity distribution is homogeneous, but when it is on the end surface after transmitting through the undoped crystal the light intensity distribution is non-homogeneous.After investigation we find that the undoped crystal affects the pumping beam, that is to say, there is total internal reflection when the pumping beam is propagating in the undoped crystal,which induces the overlap of pumping beam in partial region of end surface,then induces the non-homogeneity of pumping beam distribution in the end surface.%基于Zemax软件下的非序列模式(Non-Sequential Mode)光线追迹法,分别模拟复合结构板条介质泵浦端面和掺杂介质区工作端面上的光强度分布.由追迹结果可知,经过整形,在泵浦面强度分布均匀的泵浦光束经过非掺杂介质区传播到掺杂介质工作端面后光束分布均匀性大大降低.研究表明复合结构板条介质中非掺杂介质区影响了泵浦光束,即泵浦光在非掺杂介质区传播过程中发生全内反射,导致部分光束在实际工作端面的部分区域发生叠加,从而致使实际工作端面泵浦光束分布不均匀.
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