简要分析了脉冲整形对于TEA CO2激光倍频实验的重要性和必要性。目前,获得短脉冲的激光脉冲整形技术中,等离子体开关结构简单,而且脉冲整形效果好,是获得高质量短脉冲比较好的方法。设计了利用激光触发气体击穿产生等离子体的方式进行脉冲整形的等离子体开关,并利用电磁波在等离子体中的反射和传播对其工作原理进行了说明。利用自行研制的等离子体开关进行了TEA CO2激光脉冲整形实验,将主峰半高全宽(FWHM) 60 ns,带有长达数百纳秒的氮气拖尾的TEA CO2激光脉冲斩去拖尾、整形,得到了FWHM 30 ns的窄脉冲。在双块AgGaSe2晶体(长分别为11.7 mm和19.5 mm)倍频实验光路图中加入等离子体开关所得倍频转换效率达12.9%,比起未加等离子体开关时最高转换效率2%有明显的增加。

The essentiality and necessity of pulse shaping to second harmonic generation (SHG) experiment of laser are analyzed. At present, the plasma shutter which has compact structure and good effect on the pulse shaping is a better method by which the high-quality short pulse can be obtained. The plasma shutter in which laser triggering gas breakdown is used to shape the laser pulse is devised. The principle is explained by using reflection and transmission of electromagnetic wave in plasma. Plasma shutter is used to shape the transversely excited atmospheric pressure (TEA) CO2 laser pulse. The TEA CO2 laser pulse with full width at half maximum (FWHM) of 60 ns and the nitrogen tail of several hundred ns is shorten to the pulse with FWHM of 30 ns and free of nitrogen tail. When adding plasma shutter to the SHG experiment using two crystals, the conversion efficiency is 12.9%. This figure is bigger than 2% which is gained without plasma shutter.