长脉冲紫外预电离TE CO_2激光器

Long Pulse TE CO_2 Laser with Ultraviolet-Preionization

研制了一台增益体积为1.17 L的长脉冲紫外预电离TE CO2激光器。基于Pulser/sustainer技术,设计了独立可控的双高压开关抽运电路。在激光混合气体比CO2∶N2∶He=1∶2.5∶13,总气压30 kPa时,以6 nF的Pulser电容控制100 nF的Sustainer电容,获得稳定的辉光放电,激光比注入能量达1.607 J/(kPa.L),其中,Pulser能量不到全部注入能量的5%。另外,在保持Sustainer总电容100 nF不变的情况下,设计了两种脉冲宽度略有不同的Sustainer电路,均获得了稳定的辉光放电,实验测量了放电电压、放电电流与输出激光脉冲波形,并分析了Sustainer放电的阻抗特点。激光器采用“Z”形折叠腔结构,输出激光脉冲宽度达20μs,电光转换效率超过12.0%,最大脉冲能量为6.5 J。

A long pulse TE CO2 laser of active volume of 1.17 L with ultraviolet （UV）-preionization is developed. By the Pulser/sustainer technique, an excitation scheme with two high voltage switches independently controlled is employed. Reliable, stable operation is demonstrated for an about 20 μs pulse duration under mixtures ratio of CO2 ：N2 ： He= 1 ： 2. 5 ： 13 and total gas pressure of 30 kPa. With 6 nF pulser capacitance and 100 nF sustainer capacitance, self-sustained volume discharge is maintained over a wide sustainer voltage range, energy deposition reaches 1. 607 J/（kPa. L）. Meanwhile, with the constant total sustainer capacitance 100 nF, two sustainer schemes are experimented and stable glow discharge is obtained. The discharge voltage/current waveforms and the output laser pulse profiles are also given to illustrate the long pulse discharge and long pulse laser output. With a Zfolded resonator, maximum output laser pulse energy reaches 6.5 J and the maximum electro-optical efficiency is over 12.0%.