声光调Q CO2激光器的输出特性

Output performance of acousto-optic Q-switched CO_2 laser

采用谐振腔内插入声光调制器(AOM)的方法获得了小型CO2激光器的高重频、窄脉宽、高峰值功率输出。通过分析CO2激光器声光调Q的工作原理,利用基于小信号增益和饱和光强的耦合输出数学模型给出了激光器最佳输出镜透过率的数值解,并运用相关实验装置对该数学模型进行了实验验证。理论分析和实验结果均表明:该声光调Q CO2激光器的最佳输出镜透过率为39%。研究了激光器输出性能随脉冲重复频率的变化规律,当脉冲重复频率>1 kHz时,激光器输出峰值功率下降,这与CO2分子上能级寿命有关,并受声光调Q开关热效应的影响。实验中获得的激光器脉冲频率在1 Hz～100 kHz可调。在脉冲频率为1 kHz时,获得的激光脉冲宽度为156 ns,脉冲峰值功率为10 kW,且稳定性较好,非常适合于作激光与物质相互作用的光源。

A compact CO2 laser with short pulse duration,high peak power and high repetition was developed by using an Acousto-optic（AO） Q-switch.The operating principle of the AO Q-switch was analyzed,and the theoretical model of CO2 laser was introduced based on the small-signal gain and saturation intensity.Then the optimal numerical solution of the transmission for an output mirror was given by this model.Based on the compact CO2 laser in our laboratory,the experiments to verify the theoretical result were performed.The optimal coupling output factor gained by the theory and experiments is 39%.The variable law of laser output performance with pulse repetition frequency was researched.Results show that the peak power of the laser will fall down when the pulse repetition frequency is greater than 1 kHz,which is related to the radiation life of CO2 molecular upper energy level,and is limited by the heat effect of AO Q-switch.The range of pulse repetition frequency can be adjusted from 1 Hz to 100 kHz.When the pulse repetition frequency is 1 kHz,the measured pulse duration is 156 ns and the peak power is 10 kW.The laser has good stabilization,and is suitable for a light source used in laser-matter interaction.