采用激光功率计、光束光斑质量诊断仪及高速摄像仪，对比研究了CO2激光及YAG激光与直流TIG电弧垂直相互作用时的光束特性和电弧特性。结果表明，CO2激光穿过TIG电弧后，激光功率显著衰减，光束散焦，能量分布状态严重劣化，而且电弧电压降低，体积膨胀，甚至产生激光支持的燃烧波；而对于YbYAG激光，电弧基本不吸收激光能量，电弧对激光特性的影响可以忽略，同时电弧电压及电弧形态也没有明显变化。试验条件下，计算得TIG电弧对CO2激光和YAG激光的逆韧致吸收系数分别为14.14～26.29 m-1和1.1～2.03 m-1。同时，TIG电弧对CO2激光和YAG激光的折射率分别为0.99249～0.99454和0.99992～0.99994。TIG电弧对CO2激光的逆韧致吸收系数远高于对YAG激光的吸收率，同时，TIG电弧对YAG激光的折射率与大气相比较差异很小。这是CO2激光及YAG激光激光与电弧相互作用存在很大差异的根本原因。

The characteristics of both laser beam and TIG arc are investigated during the interaction between the vertical incident laser and TIG arc by using a laser power meter, a beam quality diagnosis instrument and a high speed camera. The experimental results demonstrate that, when CO2 laser beam passes through TIG arc, the laser power is attenuated dramatically, the beam is defocuses and even a laser supported combustion wave is generated. In this case, the beam quality is seriously worsened. On the other hand, the arc voltage is dropped and the arc column is expanded. However, the beam power, beam diameter, arc voltage and arc column seldom change during TIG arc interacted with YbYAG laser. Under the experimental conditions, the inverse bremasstrahlung absorption coefficient calculated is 14.14～26.29 m-1 for CO2 laser, 1.1～2.03 m-1 for YAG laser and the refractive index is 0.99249～0.99454 for CO2 laser, 0.99992～0.99994 for YAG laser, respectively. The inverse bremsstrahlung absorption coefficient for YAG laser is two orders of magnitude lower than that for CO2 laser. Meanwhile, there is less difference between the refractive index of YAG laser-TIG and YAG laser-air, so there is no obvious refraction of the TIG arc to the YAG laser, which is the main reason for the great difference between the CO2 laser-TIG and YAG laser-TIG interaction.