纳秒激光与靶材相互作用过程分析

利用纳秒激光在薄铜片上进行多脉冲打孔时，出现一种反常现象，在2个值处，随着单脉冲能量的提高，打1个孔所需脉冲次数不但没有减少，反而增加，根据环境气体分解消耗激光能量解释了第1处的反常现象，并首次提出了等离子体受光场力的作用，在激光作用初期，使靶表面形成一层致密的等离子体，阻挡了后续激光到达靶材，引起了第2处的反常现象。

Interaction Process Analysis of Nanosecond-laser Target Material

Extraordinary phenomena are observed when Nanosecondlaser is used to perfo rate thin copper films. As the one-pulse energy is raised, the number of pulses required for one perforation increases rather than drops at two one-pulse energy values, 85mJ and 181mJ. The anomaly at the first energy value is interpreted by laser energy loss due to dissociation of the surrounding air. The effect of opt ical forces on ablated materials causes the formation of a layer of dense ablate d materials near the target surface at early stage of the laser's action and th e layer hinders subsequent laser beam from reaching, thus resulting in the anoma ly at the second energy value.