CO_2/CO slab laser excited by high frequency

研制了电极尺寸为5 × 60cm^2的CO_2板状激光器，激发功率为80,100，频率为125MHz。气体含量为CO_2/N_2/He=1/1/8。得到的最大功率为180 ~ 200w。5mum CO激光器在20‰的温度下采用与CO_2板状激光器相同的振荡方案。两个平板激光器是耦合的，其中电极尺寸为3x16cm^2.2。磁场对平板激光器的影响。在板坯激光器中，狭缝越窄，冷却效果越好。当激光以较高的频率激发时，间隙长度可以变窄，因为接缝的深度与激发频率成反比。因此，更高的频率更适合更高的功率/cm^2，但较低的频率（如13.5MHz或27MHz）更容易处理且更便宜。当磁场垂直于电流作用于平板激光器等离子体时，电子的路径发生弯曲，频率越高，间隙长度越窄。对这种效应进行了理论分析，并在0 ~ 400高斯磁场下进行了实验。提出了两种用于星耦合平板激光器的新型不稳定谐振腔。其中，不稳定谐振腔的输出被平面镜反射回来，功率从凹面镜中心的孔径耦合出来。其中另一个凸面镜的中心在平面上，在那里构成一个稳定的谐振腔。对它们进行了理论分析，明确了星耦合平板激光器的有效性。

A CO_2 slab laser was developed, of which size of electrodes are 5x60cm^2, excited by 80,100, and 125MHz RF power. The gas content is CO_2/N_2/He=1/1/8. The maximum power obtained are 180-200W.5mum CO laser also oscillated with the same scheme of CO_2 slab laser at 20ﾟC.The two slab lasers are coupled, of which sizes of electrodes are 3x16cm^2.2.The effect of magnetic field on the slab laser.The cooling is more effective for the narrower gap length in the slab laser. The gap length can be narrower when the laser is excited with the higher frequency, because the depth of the seath is inversely proportional to the excited frequency. So, the higher frequency is preferable for the higher power/cm^2, but the lower frequency such as 13.5MHz or 27MHz are easier to handle and cheaper.When the magnetic field is applied to the plasma of slab laser, perpendicularly to the current, the path of the electron is bent and the gap length can be narrower for the higher frequency.This effect has been theoretically analyzed and the experiment with 0-400 Gauss magnetic field is going on.3.The two types of new unstable resonators are proposed for the star-coupled slab lasers. In one which the output from the unstable resonator is reflected back by the flat mirror, and the power is coupled out from the aperture at the center of the concave mirror. In other of which the center of the convex mirror in flat, to constitute a stable resonator there. They are theoretically analyzed and the effectiveness become clear for the star-coupled slab lasers.