封离式He-N_2-CO_2激光器横模特性的测量与分析

Measurement and analysis of the characteristics of transverse modes of a sealed-off He-N_2-CO_2 laser

利用激光光束分析仪,实时在线测量了一根He-N2-CO2封离式激光管的横模分布特性,得到了激光模式随放电电流的变化关系.实验表明该激光器在最佳工作电流时,容易形成低阶模运转,但很难获得基模运转,通过改善对称性以及加快冷却水流速可以获得基模运转.通过激光动力学过程分析了模式变化的形成原因,为大功率激光器模式控制与改善提供了一定的理论和实验借鉴.

The characteristics of the transverse modes of a sealed-off He-N2-CO2 laser are measured on-line by using a laser beam analyzer. The influence of the transverse modes on discharge current is observed. It is shown that this laser tube can easily operate on lower order modes under optimum discharge current, but hardly operate on the TEM00 mode. Under the condition of improved symmetry of laser tube and increasing the speed of cooling water, the laser can operate on the TEM00 mode. The variety of laser modes is analyzed through the kinetic process theoretically, which is helpful to the control and improvement of laser mode for high power lasers.