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研究了激光加工用大功率ＣＯ２激光束在飞行光学导光系统中传输所产生的空气热透镜效应。实验发现当飞行光学导光系统中的空气静止时将产生空气热透镜效应，而充以一定压力的压缩空气却可以消除空气热透镜效应。实验表明无热透镜效应时，光束遵循高斯光束传输规律，而有热透镜效应时，光束偏离高斯光束的传输规律，并影响到激光束聚焦焦点的大小和位置。另外通过激光空气热透镜效应的非线性模型计算了热透镜效应所引起的光束传输相对高斯光束的偏离量，理论计算和实验测量相吻合。在此基础上提出了热透镜效应引起光束传输虚束腰和赝束腰的概念，并指出应采用虚束腰来推导光束的传输与聚焦特性
The effect of air thermal lens produced by the transmission of high power CO2 laser beam in the flight optical guiding system was studied. The experiment found that the air thermal lens effect will occur when the air in the flight optical light guide system is stationary, and the compressed air with a certain pressure can eliminate the air thermal lens effect. Experiments show that there is no thermal lens effect, the beam follows Gaussian beam transmission law, and the thermal lens effect, the deviation of the beam from Gaussian beam transmission and affect the size and location of the focus of the laser beam focus. In addition, the non-linear model of the thermal lens effect of laser air is used to calculate the deviation of Gaussian beam caused by the thermal lens effect, which is in good agreement with the theoretical calculation. On the basis of this, the concept of thermal lens effect caused by the beam transmission in the virtual beam waist and the pseudo-beam waist is proposed, and the virtual beam waist should be used to derive the transmission and focusing characteristics of the beam