低热效应高光束质量自倍频黄光激光器

Self-Frequency Doubling Yellow Laser with Low Thermal Effect and High Beam Quality

自倍频激光器的发展很大程度受到热效应的限制,为了减弱激光器热效应,获得更高光束质量的黄光激光输出,提出了1020 nm激光同带泵浦Yb:YCOB自倍频晶体的黄光激光器。通过理论分析,对比传统976 nm激光二极管泵浦方式,解释了自倍频晶体吸收泵浦光能量所产生的热透镜效应对光学倍频过程中相位匹配条件的影响,阐明了1020 nm同带泵浦方式光束质量提升的原因。并通过实验获得了更高光束质量的570 nm黄光激光输出,光束质量因子M_(x)^(2)=1.41,M_(y)^(2)=1.87。研究结果表明,1020 nm波长泵浦方式下出射光束质量较传统976 nm泵浦方式有明显的提高,且谱宽更窄。该研究对于降低Yb∶YCOB自倍频激光器热效应,获得光束质量较高、谱宽更窄的高功率黄光激光器具有指导作用。

The development of self-frequency doubling lasers has been significantly limited owing to the thermal effect.To reduce the thermal effect of lasers and obtain higher beam quality yellow laser output,a Yb∶YCOB self-frequency doubling crystal yellow laser pumped by a 1020-nm laser is proposed.The influence of the thermal lens effect,because of the self-frequency doubling crystal-absorbing pump light energy,on the phase matching condition during the process of optical frequency doubling is explained on the basis of a theoretical analysis.Furthermore,the analysis also yields an explanation for the improvement in the quality of the 1020-nm single-band pumping mode beam,as compared with that of the traditional 976-nm laser diode pumping mode.A 570-nm yellow laser with higher beam quality is obtained through experiments.The beam quality factors correspond to M_(x)^(2)=1.41 and M_(y)^(2)=1.87.The results indicate that the quality of the outgoing beam at a wavelength of 1020 nm is significantly higher than that at 976 nm,and the spectrum width is narrower.The results of the study play a guiding role in reducing the thermal effect of Yb∶YCOB self-frequency doubling lasers and obtaining high-power yellow lasers with higher beam quality and narrower spectrum width.