激光点火性能与边界条件具有密切关系,影响到激光点火的感度和点火延迟时间,对激光点火元件的设计具有关键作用。针对空气介质,K9玻璃透窗介质和在K9玻璃上真空磁控溅射镀制的Cu膜介质等3种边界条件,对B/KNO3和B/KNO3/酚醛树脂的1.06 μm脉冲激光点火性能进行了实验测试。结果表明,K9透窗对约束药剂表面烧蚀、气化产生的蒸气有显著作用,可以明显增加药剂点火感度并减少药剂点火延滞期;镀膜透窗增强了点火过程中药剂表面的等离子体,减少了点火延滞期,但却由于铜膜对激光的反射以及产生等离子体所消耗的能量,降低了点火感度。

The confinement has important effects on the capability of laser ignition. It can affect the delay time and the ignition threshold of energetic materials. So it is of key importance in the design of laser ignition element. Experiments were done to research the effects of confinement on the ignition capability of B/KNO3 and B/KNO3/ phenolic resin by the laser whose wavelength is 1.06 μm. Three kinds of confinement were used. They were air,K9 glass,and K9 glass deposited with copper film. The results show that when reactions occur near to the surface,gaseous products are confined by K9 glass,and the high external pressure will augment the ignition threshold of energetic materials and reduce the delay time. The effect of the K9 glass deposited with copper film is to enhance the plasma near the surface of energetic materials,which reduces the delay time but lowers the ignition threshold,because the copper film reflects a part of the laser and a big part energy of the laser is used to generate the copper plasma.