CCD测量LD端面抽运Nd∶GdVO_4固体激光器热焦距

为研究Nd∶GdVO4晶体在激光二极管(LD)端面抽运固体激光器中的热效应,给出了一种测量激光器稳态运转时腔内激活介质热透镜焦距的简便方法。采用CCD光束分析仪直接测量输出光束的M2因子及束腰大小,根据混合模类高斯光束传输理论推导出相应的基模高斯光束束腰大小,由此利用稳定谐振腔的传输矩阵理论可得到相应的激光介质的热焦距。实验结果表明,抽运功率越高,热焦距越小,热效应对输出光束质量影响越严重。基于上述原理,对LD端面抽运的Nd∶GdVO4固体激光器热透镜焦距进行了测量,实验结果和理论分析相符。

Determining the thermal lens focus of LD end-pumped Nd∶GdVO4solid-state laser with CCD detecting method

In order to study the thermal effect of Nd∶GdVO4 crystal in LD end-pumped solid-state laser,a simply method to measure the thermal focal length with stable resonator is presented. By measuring M2 factor and the waist of output beam with CCD beam analyzer,the beam waist of the TEM00 mode can be deduced according to the law of multi-mode Gaussian beam propagation.Based on the ABCD matrix theory of stable resonator,the thermal focal length of the active medium is easily obtained. The experiment shows that the higher the pump power is,the smaller the thermal focal length is,and the worse the thermal effect influent the output beam quality. The thermal focal length of a LD end-pumped Nd∶GdVO4 laser is measured and the experimental results agree with the theoretical predication.